From 7f203bc89eb66d6afde7eae91347fc0352090cc3 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Fri, 29 Jul 2022 13:10:16 -1000
Subject: [PATCH 01/25] cgroup: Replace cgroup->ancestor_ids[] with
->ancestors[]
Every cgroup knows all its ancestors through its ->ancestor_ids[]. There's
no advantage to remembering the IDs instead of the pointers directly and
this makes the array useless for finding an actual ancestor cgroup forcing
cgroup_ancestor() to iteratively walk up the hierarchy instead. Let's
replace cgroup->ancestor_ids[] with ->ancestors[] and remove the walking-up
from cgroup_ancestor().
While at it, improve comments around cgroup_root->cgrp_ancestor_storage.
This patch shouldn't cause user-visible behavior differences.
v2: Update cgroup_ancestor() to use ->ancestors[].
v3: cgroup_root->cgrp_ancestor_storage's type is updated to match
cgroup->ancestors[]. Better comments.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
---
include/linux/cgroup-defs.h | 16 ++++++++++------
include/linux/cgroup.h | 8 +++-----
kernel/cgroup/cgroup.c | 7 +++----
net/netfilter/nft_socket.c | 9 +++++----
tools/perf/util/bpf_skel/bperf_cgroup.bpf.c | 2 +-
5 files changed, 22 insertions(+), 20 deletions(-)
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 4bcf56b3491ca..1283993d7ea8f 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -384,7 +384,7 @@ struct cgroup {
/*
* The depth this cgroup is at. The root is at depth zero and each
* step down the hierarchy increments the level. This along with
- * ancestor_ids[] can determine whether a given cgroup is a
+ * ancestors[] can determine whether a given cgroup is a
* descendant of another without traversing the hierarchy.
*/
int level;
@@ -504,8 +504,8 @@ struct cgroup {
/* Used to store internal freezer state */
struct cgroup_freezer_state freezer;
- /* ids of the ancestors at each level including self */
- u64 ancestor_ids[];
+ /* All ancestors including self */
+ struct cgroup *ancestors[];
};
/*
@@ -522,11 +522,15 @@ struct cgroup_root {
/* Unique id for this hierarchy. */
int hierarchy_id;
- /* The root cgroup. Root is destroyed on its release. */
+ /*
+ * The root cgroup. The containing cgroup_root will be destroyed on its
+ * release. cgrp->ancestors[0] will be used overflowing into the
+ * following field. cgrp_ancestor_storage must immediately follow.
+ */
struct cgroup cgrp;
- /* for cgrp->ancestor_ids[0] */
- u64 cgrp_ancestor_id_storage;
+ /* must follow cgrp for cgrp->ancestors[0], see above */
+ struct cgroup *cgrp_ancestor_storage;
/* Number of cgroups in the hierarchy, used only for /proc/cgroups */
atomic_t nr_cgrps;
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index ed53bfe7c46c4..4d143729b2468 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -574,7 +574,7 @@ static inline bool cgroup_is_descendant(struct cgroup *cgrp,
{
if (cgrp->root != ancestor->root || cgrp->level < ancestor->level)
return false;
- return cgrp->ancestor_ids[ancestor->level] == cgroup_id(ancestor);
+ return cgrp->ancestors[ancestor->level] == ancestor;
}
/**
@@ -591,11 +591,9 @@ static inline bool cgroup_is_descendant(struct cgroup *cgrp,
static inline struct cgroup *cgroup_ancestor(struct cgroup *cgrp,
int ancestor_level)
{
- if (cgrp->level < ancestor_level)
+ if (ancestor_level < 0 || ancestor_level > cgrp->level)
return NULL;
- while (cgrp && cgrp->level > ancestor_level)
- cgrp = cgroup_parent(cgrp);
- return cgrp;
+ return cgrp->ancestors[ancestor_level];
}
/**
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index ffaccd6373f1e..627ff0f07da75 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -2049,7 +2049,7 @@ int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
}
root_cgrp->kn = kernfs_root_to_node(root->kf_root);
WARN_ON_ONCE(cgroup_ino(root_cgrp) != 1);
- root_cgrp->ancestor_ids[0] = cgroup_id(root_cgrp);
+ root_cgrp->ancestors[0] = root_cgrp;
ret = css_populate_dir(&root_cgrp->self);
if (ret)
@@ -5400,8 +5400,7 @@ static struct cgroup *cgroup_create(struct cgroup *parent, const char *name,
int ret;
/* allocate the cgroup and its ID, 0 is reserved for the root */
- cgrp = kzalloc(struct_size(cgrp, ancestor_ids, (level + 1)),
- GFP_KERNEL);
+ cgrp = kzalloc(struct_size(cgrp, ancestors, (level + 1)), GFP_KERNEL);
if (!cgrp)
return ERR_PTR(-ENOMEM);
@@ -5453,7 +5452,7 @@ static struct cgroup *cgroup_create(struct cgroup *parent, const char *name,
spin_lock_irq(&css_set_lock);
for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp)) {
- cgrp->ancestor_ids[tcgrp->level] = cgroup_id(tcgrp);
+ cgrp->ancestors[tcgrp->level] = tcgrp;
if (tcgrp != cgrp) {
tcgrp->nr_descendants++;
diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
index a7de29137618a..49a5348a6a14f 100644
--- a/net/netfilter/nft_socket.c
+++ b/net/netfilter/nft_socket.c
@@ -40,16 +40,17 @@ static noinline bool
nft_sock_get_eval_cgroupv2(u32 *dest, struct sock *sk, const struct nft_pktinfo *pkt, u32 level)
{
struct cgroup *cgrp;
+ u64 cgid;
if (!sk_fullsock(sk))
return false;
- cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
- if (level > cgrp->level)
+ cgrp = cgroup_ancestor(sock_cgroup_ptr(&sk->sk_cgrp_data), level);
+ if (!cgrp)
return false;
- memcpy(dest, &cgrp->ancestor_ids[level], sizeof(u64));
-
+ cgid = cgroup_id(cgrp);
+ memcpy(dest, &cgid, sizeof(u64));
return true;
}
#endif
diff --git a/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c b/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
index 292c430768b52..bd6a420acc8f1 100644
--- a/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
+++ b/tools/perf/util/bpf_skel/bperf_cgroup.bpf.c
@@ -68,7 +68,7 @@ static inline int get_cgroup_v1_idx(__u32 *cgrps, int size)
break;
// convert cgroup-id to a map index
- cgrp_id = BPF_CORE_READ(cgrp, ancestor_ids[i]);
+ cgrp_id = BPF_CORE_READ(cgrp, ancestors[i], kn, id);
elem = bpf_map_lookup_elem(&cgrp_idx, &cgrp_id);
if (!elem)
continue;
From 74e4b956eb1cac0e4c10c240339b1bbfbc9a4c48 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michal=20Koutn=C3=BD?= <mkoutny@suse.com>
Date: Fri, 26 Aug 2022 18:52:35 +0200
Subject: [PATCH 02/25] cgroup: Honor caller's cgroup NS when resolving path
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
cgroup_get_from_path() is not widely used function. Its callers presume
the path is resolved under cgroup namespace. (There is one caller
currently and resolving in init NS won't make harm (netfilter). However,
future users may be subject to different effects when resolving
globally.)
Since, there's currently no use for the global resolution, modify the
existing function to take cgroup NS into account.
Fixes: a79a908fd2b0 ("cgroup: introduce cgroup namespaces")
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/cgroup.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 627ff0f07da75..1c7ab41092516 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -6602,8 +6602,12 @@ struct cgroup *cgroup_get_from_path(const char *path)
{
struct kernfs_node *kn;
struct cgroup *cgrp = ERR_PTR(-ENOENT);
+ struct cgroup *root_cgrp;
- kn = kernfs_walk_and_get(cgrp_dfl_root.cgrp.kn, path);
+ spin_lock_irq(&css_set_lock);
+ root_cgrp = current_cgns_cgroup_from_root(&cgrp_dfl_root);
+ kn = kernfs_walk_and_get(root_cgrp->kn, path);
+ spin_unlock_irq(&css_set_lock);
if (!kn)
goto out;
From 4534dee941056a4ab9dca4a9e2edff28692800b2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michal=20Koutn=C3=BD?= <mkoutny@suse.com>
Date: Fri, 26 Aug 2022 18:52:36 +0200
Subject: [PATCH 03/25] cgroup: cgroup: Honor caller's cgroup NS when resolving
cgroup id
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Cgroup ids are resolved in the global scope. That may be needed sometime
(in future) but currently it violates virtual view provided through
cgroup namespaces.
There are currently following users of the resolution:
- fc_appid_store
- bpf_iter_attach_cgroup
- mem_cgroup_get_from_ino
None of the is a called on behalf of kernel but the resolution is made
with proper userspace context, hence the default to current->nsproxy
makes sens. (This doesn't rule out cgroup_get_from_id with cgroup NS
parameter in the future.)
Since cgroup ids are defined on v2 hierarchy only, we simply check
existence in the cgroup namespace by looking at ancestry on the default
hierarchy.
Fixes: 6b658c4863c1 ("scsi: cgroup: Add cgroup_get_from_id()")
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/cgroup.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 1c7ab41092516..3229f35587662 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -6006,11 +6006,12 @@ void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
* cgroup_get_from_id : get the cgroup associated with cgroup id
* @id: cgroup id
* On success return the cgrp, on failure return NULL
+ * Only cgroups within current task's cgroup NS are valid.
*/
struct cgroup *cgroup_get_from_id(u64 id)
{
struct kernfs_node *kn;
- struct cgroup *cgrp = NULL;
+ struct cgroup *cgrp = NULL, *root_cgrp;
kn = kernfs_find_and_get_node_by_id(cgrp_dfl_root.kf_root, id);
if (!kn)
@@ -6023,8 +6024,18 @@ struct cgroup *cgroup_get_from_id(u64 id)
cgrp = NULL;
rcu_read_unlock();
-
kernfs_put(kn);
+
+ if (!cgrp)
+ goto out;
+
+ spin_lock_irq(&css_set_lock);
+ root_cgrp = current_cgns_cgroup_from_root(&cgrp_dfl_root);
+ spin_unlock_irq(&css_set_lock);
+ if (!cgroup_is_descendant(cgrp, root_cgrp)) {
+ cgroup_put(cgrp);
+ cgrp = NULL;
+ }
out:
return cgrp;
}
From fa7e439cf90ba23ea473d0b7d85efd02ae6ccf94 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Michal=20Koutn=C3=BD?= <mkoutny@suse.com>
Date: Fri, 26 Aug 2022 18:52:37 +0200
Subject: [PATCH 04/25] cgroup: Homogenize cgroup_get_from_id() return value
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Cgroup id is user provided datum hence extend its return domain to
include possible error reason (similar to cgroup_get_from_fd()).
This change also fixes commit d4ccaf58a847 ("bpf: Introduce cgroup
iter") that would use NULL instead of proper error handling in
d4ccaf58a847 ("bpf: Introduce cgroup iter").
Additionally, neither of: fc_appid_store, bpf_iter_attach_cgroup,
mem_cgroup_get_from_ino (callers of cgroup_get_from_fd) is built without
CONFIG_CGROUPS (depends via CONFIG_BLK_CGROUP, direct, transitive
CONFIG_MEMCG respectively) transitive, so drop the singular definition
not needed with !CONFIG_CGROUPS.
Fixes: d4ccaf58a847 ("bpf: Introduce cgroup iter")
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
block/blk-cgroup-fc-appid.c | 4 ++--
include/linux/cgroup.h | 5 -----
kernel/cgroup/cgroup.c | 4 ++--
mm/memcontrol.c | 4 ++--
4 files changed, 6 insertions(+), 11 deletions(-)
diff --git a/block/blk-cgroup-fc-appid.c b/block/blk-cgroup-fc-appid.c
index 760a2e1878dde..842e5e1c0f3cb 100644
--- a/block/blk-cgroup-fc-appid.c
+++ b/block/blk-cgroup-fc-appid.c
@@ -19,8 +19,8 @@ int blkcg_set_fc_appid(char *app_id, u64 cgrp_id, size_t app_id_len)
return -EINVAL;
cgrp = cgroup_get_from_id(cgrp_id);
- if (!cgrp)
- return -ENOENT;
+ if (IS_ERR(cgrp))
+ return PTR_ERR(cgrp);
css = cgroup_get_e_css(cgrp, &io_cgrp_subsys);
if (!css) {
ret = -ENOENT;
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 4d143729b2468..30ee8ce2665e7 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -750,11 +750,6 @@ static inline bool task_under_cgroup_hierarchy(struct task_struct *task,
static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
{}
-
-static inline struct cgroup *cgroup_get_from_id(u64 id)
-{
- return NULL;
-}
#endif /* !CONFIG_CGROUPS */
#ifdef CONFIG_CGROUPS
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 3229f35587662..a8780ef3b7693 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -6005,7 +6005,7 @@ void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
/*
* cgroup_get_from_id : get the cgroup associated with cgroup id
* @id: cgroup id
- * On success return the cgrp, on failure return NULL
+ * On success return the cgrp or ERR_PTR on failure
* Only cgroups within current task's cgroup NS are valid.
*/
struct cgroup *cgroup_get_from_id(u64 id)
@@ -6037,7 +6037,7 @@ struct cgroup *cgroup_get_from_id(u64 id)
cgrp = NULL;
}
out:
- return cgrp;
+ return cgrp ?: ERR_PTR(-ENOENT);
}
EXPORT_SYMBOL_GPL(cgroup_get_from_id);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index b69979c9ced5c..86f5ca8c6fa62 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5110,8 +5110,8 @@ struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino)
struct mem_cgroup *memcg;
cgrp = cgroup_get_from_id(ino);
- if (!cgrp)
- return ERR_PTR(-ENOENT);
+ if (IS_ERR(cgrp))
+ return PTR_ERR(cgrp);
css = cgroup_get_e_css(cgrp, &memory_cgrp_subsys);
if (css)
From 075b593f54f0f3883532cb750081cae6917bc8fe Mon Sep 17 00:00:00 2001
From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Date: Fri, 26 Aug 2022 11:48:29 +0900
Subject: [PATCH 05/25] cgroup: Use cgroup_attach_{lock,unlock}() from
cgroup_attach_task_all()
No behavior changes; preparing for potential locking changes in future.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by:Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/cgroup-internal.h | 2 ++
kernel/cgroup/cgroup-v1.c | 6 ++----
kernel/cgroup/cgroup.c | 4 ++--
3 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/kernel/cgroup/cgroup-internal.h b/kernel/cgroup/cgroup-internal.h
index 36b740cb3d59e..2c7ecca226be8 100644
--- a/kernel/cgroup/cgroup-internal.h
+++ b/kernel/cgroup/cgroup-internal.h
@@ -250,6 +250,8 @@ int cgroup_migrate(struct task_struct *leader, bool threadgroup,
int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
bool threadgroup);
+void cgroup_attach_lock(bool lock_threadgroup);
+void cgroup_attach_unlock(bool lock_threadgroup);
struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup,
bool *locked)
__acquires(&cgroup_threadgroup_rwsem);
diff --git a/kernel/cgroup/cgroup-v1.c b/kernel/cgroup/cgroup-v1.c
index ff6a8099eb2a2..52bb5a74a23b9 100644
--- a/kernel/cgroup/cgroup-v1.c
+++ b/kernel/cgroup/cgroup-v1.c
@@ -59,8 +59,7 @@ int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk)
int retval = 0;
mutex_lock(&cgroup_mutex);
- cpus_read_lock();
- percpu_down_write(&cgroup_threadgroup_rwsem);
+ cgroup_attach_lock(true);
for_each_root(root) {
struct cgroup *from_cgrp;
@@ -72,8 +71,7 @@ int cgroup_attach_task_all(struct task_struct *from, struct task_struct *tsk)
if (retval)
break;
}
- percpu_up_write(&cgroup_threadgroup_rwsem);
- cpus_read_unlock();
+ cgroup_attach_unlock(true);
mutex_unlock(&cgroup_mutex);
return retval;
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 65497a1a44fa8..0005de2e2ed9a 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -2393,7 +2393,7 @@ EXPORT_SYMBOL_GPL(task_cgroup_path);
* write-locking cgroup_threadgroup_rwsem. This allows ->attach() to assume that
* CPU hotplug is disabled on entry.
*/
-static void cgroup_attach_lock(bool lock_threadgroup)
+void cgroup_attach_lock(bool lock_threadgroup)
{
cpus_read_lock();
if (lock_threadgroup)
@@ -2404,7 +2404,7 @@ static void cgroup_attach_lock(bool lock_threadgroup)
* cgroup_attach_unlock - Undo cgroup_attach_lock()
* @lock_threadgroup: whether to up_write cgroup_threadgroup_rwsem
*/
-static void cgroup_attach_unlock(bool lock_threadgroup)
+void cgroup_attach_unlock(bool lock_threadgroup)
{
if (lock_threadgroup)
percpu_up_write(&cgroup_threadgroup_rwsem);
From c0f2df49cf2471289d5aabf16f50ac26eb268f7d Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Sun, 28 Aug 2022 17:54:15 -1000
Subject: [PATCH 06/25] cgroup: Fix build failure when CONFIG_SHRINKER_DEBUG
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
fa7e439cf90b ("cgroup: Homogenize cgroup_get_from_id() return value") broken
build when CONFIG_SHRINKER_DEBUG by trying to return an errno from
mem_cgroup_get_from_ino() which returns struct mem_cgroup *. Fix by using
ERR_CAST() instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Michal Koutný <mkoutny@suse.com>f
Fixes: fa7e439cf90b ("cgroup: Homogenize cgroup_get_from_id() return value")
---
mm/memcontrol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 86f5ca8c6fa62..e9fc364d5e962 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -5111,7 +5111,7 @@ struct mem_cgroup *mem_cgroup_get_from_ino(unsigned long ino)
cgrp = cgroup_get_from_id(ino);
if (IS_ERR(cgrp))
- return PTR_ERR(cgrp);
+ return ERR_CAST(cgrp);
css = cgroup_get_e_css(cgrp, &memory_cgrp_subsys);
if (css)
From dc79ec1b232ad2c165d381d3dd2626df4ef9b5a4 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Sun, 4 Sep 2022 09:16:19 -1000
Subject: [PATCH 07/25] cgroup: Remove data-race around cgrp_dfl_visible
There's a seemingly harmless data-race around cgrp_dfl_visible detected by
kernel concurrency sanitizer. Let's remove it by throwing WRITE/READ_ONCE at
it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Abhishek Shah <abhishek.shah@columbia.edu>
Cc: Gabriel Ryan <gabe@cs.columbia.edu>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Link: https://lore.kernel.org/netdev/20220819072256.fn7ctciefy4fc4cu@wittgenstein/
---
kernel/cgroup/cgroup.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 0005de2e2ed9a..e0b72eb5d283b 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -2173,7 +2173,7 @@ static int cgroup_get_tree(struct fs_context *fc)
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
int ret;
- cgrp_dfl_visible = true;
+ WRITE_ONCE(cgrp_dfl_visible, true);
cgroup_get_live(&cgrp_dfl_root.cgrp);
ctx->root = &cgrp_dfl_root;
@@ -6098,7 +6098,7 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
struct cgroup *cgrp;
int ssid, count = 0;
- if (root == &cgrp_dfl_root && !cgrp_dfl_visible)
+ if (root == &cgrp_dfl_root && !READ_ONCE(cgrp_dfl_visible))
continue;
seq_printf(m, "%d:", root->hierarchy_id);
From 5251c6c436edf81e5f27de31ca34bcdc12fc94e1 Mon Sep 17 00:00:00 2001
From: Josh Don <joshdon@google.com>
Date: Wed, 31 Aug 2022 15:49:03 -0700
Subject: [PATCH 08/25] cgroup: add pids.peak interface for pids controller
pids.peak tracks the high watermark of usage for number of pids. This
helps give a better baseline on which to set pids.max. Polling
pids.current isn't really feasible, since it would potentially miss
short-lived spikes.
This interface is analogous to memory.peak.
Signed-off-by: Josh Don <joshdon@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/pids.c | 37 +++++++++++++++++++++++++++++++++++--
1 file changed, 35 insertions(+), 2 deletions(-)
diff --git a/kernel/cgroup/pids.c b/kernel/cgroup/pids.c
index 511af87f685e8..7695e60bcb409 100644
--- a/kernel/cgroup/pids.c
+++ b/kernel/cgroup/pids.c
@@ -47,6 +47,7 @@ struct pids_cgroup {
*/
atomic64_t counter;
atomic64_t limit;
+ int64_t watermark;
/* Handle for "pids.events" */
struct cgroup_file events_file;
@@ -85,6 +86,16 @@ static void pids_css_free(struct cgroup_subsys_state *css)
kfree(css_pids(css));
}
+static void pids_update_watermark(struct pids_cgroup *p, int64_t nr_pids)
+{
+ /*
+ * This is racy, but we don't need perfectly accurate tallying of
+ * the watermark, and this lets us avoid extra atomic overhead.
+ */
+ if (nr_pids > READ_ONCE(p->watermark))
+ WRITE_ONCE(p->watermark, nr_pids);
+}
+
/**
* pids_cancel - uncharge the local pid count
* @pids: the pid cgroup state
@@ -128,8 +139,11 @@ static void pids_charge(struct pids_cgroup *pids, int num)
{
struct pids_cgroup *p;
- for (p = pids; parent_pids(p); p = parent_pids(p))
- atomic64_add(num, &p->counter);
+ for (p = pids; parent_pids(p); p = parent_pids(p)) {
+ int64_t new = atomic64_add_return(num, &p->counter);
+
+ pids_update_watermark(p, new);
+ }
}
/**
@@ -156,6 +170,12 @@ static int pids_try_charge(struct pids_cgroup *pids, int num)
*/
if (new > limit)
goto revert;
+
+ /*
+ * Not technically accurate if we go over limit somewhere up
+ * the hierarchy, but that's tolerable for the watermark.
+ */
+ pids_update_watermark(p, new);
}
return 0;
@@ -311,6 +331,14 @@ static s64 pids_current_read(struct cgroup_subsys_state *css,
return atomic64_read(&pids->counter);
}
+static s64 pids_peak_read(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ struct pids_cgroup *pids = css_pids(css);
+
+ return READ_ONCE(pids->watermark);
+}
+
static int pids_events_show(struct seq_file *sf, void *v)
{
struct pids_cgroup *pids = css_pids(seq_css(sf));
@@ -331,6 +359,11 @@ static struct cftype pids_files[] = {
.read_s64 = pids_current_read,
.flags = CFTYPE_NOT_ON_ROOT,
},
+ {
+ .name = "peak",
+ .flags = CFTYPE_NOT_ON_ROOT,
+ .read_s64 = pids_peak_read,
+ },
{
.name = "events",
.seq_show = pids_events_show,
From ec5fbdfb99d18482619ac42605cb80fbb56068ee Mon Sep 17 00:00:00 2001
From: Waiman Long <longman@redhat.com>
Date: Thu, 1 Sep 2022 16:57:36 -0400
Subject: [PATCH 09/25] cgroup/cpuset: Enable update_tasks_cpumask() on
top_cpuset
Previously, update_tasks_cpumask() is not supposed to be called with
top cpuset. With cpuset partition that takes CPUs away from the top
cpuset, adjusting the cpus_mask of the tasks in the top cpuset is
necessary. Percpu kthreads, however, are ignored.
Fixes: ee8dde0cd2ce ("cpuset: Add new v2 cpuset.sched.partition flag")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/cpuset.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 1f3a55297f39d..50bf837571ac8 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -33,6 +33,7 @@
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/kmod.h>
+#include <linux/kthread.h>
#include <linux/list.h>
#include <linux/mempolicy.h>
#include <linux/mm.h>
@@ -1127,10 +1128,18 @@ static void update_tasks_cpumask(struct cpuset *cs)
{
struct css_task_iter it;
struct task_struct *task;
+ bool top_cs = cs == &top_cpuset;
css_task_iter_start(&cs->css, 0, &it);
- while ((task = css_task_iter_next(&it)))
+ while ((task = css_task_iter_next(&it))) {
+ /*
+ * Percpu kthreads in top_cpuset are ignored
+ */
+ if (top_cs && (task->flags & PF_KTHREAD) &&
+ kthread_is_per_cpu(task))
+ continue;
set_cpus_allowed_ptr(task, cs->effective_cpus);
+ }
css_task_iter_end(&it);
}
@@ -2092,12 +2101,7 @@ static int update_prstate(struct cpuset *cs, int new_prs)
update_flag(CS_CPU_EXCLUSIVE, cs, 0);
}
- /*
- * Update cpumask of parent's tasks except when it is the top
- * cpuset as some system daemons cannot be mapped to other CPUs.
- */
- if (parent != &top_cpuset)
- update_tasks_cpumask(parent);
+ update_tasks_cpumask(parent);
if (parent->child_ecpus_count)
update_sibling_cpumasks(parent, cs, &tmpmask);
From 18065ebe9b3359b163324f3fb36f7edeb73503e2 Mon Sep 17 00:00:00 2001
From: Waiman Long <longman@redhat.com>
Date: Thu, 1 Sep 2022 16:57:37 -0400
Subject: [PATCH 10/25] cgroup/cpuset: Miscellaneous cleanups & add helper
functions
The partition root state (PRS) macro names do not currently match the
external names. Change them to match the external names and add helper
functions to read or change the state.
Shorten the cpuset argument of update_parent_subparts_cpumask() to cs
to match other cpuset functions.
Remove the new_prs argument from notify_partition_change() as the
cs->partition_root_state has already been set to new_prs before it
is called.
There is no functional change.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/cpuset.c | 169 ++++++++++++++++++++++-------------------
1 file changed, 90 insertions(+), 79 deletions(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 50bf837571ac8..68404e4885040 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -176,20 +176,18 @@ struct cpuset {
/*
* Partition root states:
*
- * 0 - not a partition root
- *
+ * 0 - member (not a partition root)
* 1 - partition root
- *
* -1 - invalid partition root
- * None of the cpus in cpus_allowed can be put into the parent's
- * subparts_cpus. In this case, the cpuset is not a real partition
- * root anymore. However, the CPU_EXCLUSIVE bit will still be set
- * and the cpuset can be restored back to a partition root if the
- * parent cpuset can give more CPUs back to this child cpuset.
*/
-#define PRS_DISABLED 0
-#define PRS_ENABLED 1
-#define PRS_ERROR -1
+#define PRS_MEMBER 0
+#define PRS_ROOT 1
+#define PRS_INVALID_ROOT -1
+
+static inline bool is_prs_invalid(int prs_state)
+{
+ return prs_state < 0;
+}
/*
* Temporary cpumasks for working with partitions that are passed among
@@ -269,25 +267,38 @@ static inline int is_spread_slab(const struct cpuset *cs)
return test_bit(CS_SPREAD_SLAB, &cs->flags);
}
-static inline int is_partition_root(const struct cpuset *cs)
+static inline int is_partition_valid(const struct cpuset *cs)
{
return cs->partition_root_state > 0;
}
+static inline int is_partition_invalid(const struct cpuset *cs)
+{
+ return cs->partition_root_state < 0;
+}
+
+/*
+ * Callers should hold callback_lock to modify partition_root_state.
+ */
+static inline void make_partition_invalid(struct cpuset *cs)
+{
+ cs->partition_root_state = PRS_INVALID_ROOT;
+}
+
/*
* Send notification event of whenever partition_root_state changes.
*/
-static inline void notify_partition_change(struct cpuset *cs,
- int old_prs, int new_prs)
+static inline void notify_partition_change(struct cpuset *cs, int old_prs)
{
- if (old_prs != new_prs)
- cgroup_file_notify(&cs->partition_file);
+ if (old_prs == cs->partition_root_state)
+ return;
+ cgroup_file_notify(&cs->partition_file);
}
static struct cpuset top_cpuset = {
.flags = ((1 << CS_ONLINE) | (1 << CS_CPU_EXCLUSIVE) |
(1 << CS_MEM_EXCLUSIVE)),
- .partition_root_state = PRS_ENABLED,
+ .partition_root_state = PRS_ROOT,
};
/**
@@ -876,7 +887,7 @@ static int generate_sched_domains(cpumask_var_t **domains,
csa[csn++] = cp;
/* skip @cp's subtree if not a partition root */
- if (!is_partition_root(cp))
+ if (!is_partition_valid(cp))
pos_css = css_rightmost_descendant(pos_css);
}
rcu_read_unlock();
@@ -1082,7 +1093,7 @@ static void rebuild_sched_domains_locked(void)
if (top_cpuset.nr_subparts_cpus) {
rcu_read_lock();
cpuset_for_each_descendant_pre(cs, pos_css, &top_cpuset) {
- if (!is_partition_root(cs)) {
+ if (!is_partition_valid(cs)) {
pos_css = css_rightmost_descendant(pos_css);
continue;
}
@@ -1216,11 +1227,11 @@ enum subparts_cmd {
* cpumask changes that violates the cpu exclusivity rule will not be
* permitted when checked by validate_change().
*/
-static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
+static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
struct cpumask *newmask,
struct tmpmasks *tmp)
{
- struct cpuset *parent = parent_cs(cpuset);
+ struct cpuset *parent = parent_cs(cs);
int adding; /* Moving cpus from effective_cpus to subparts_cpus */
int deleting; /* Moving cpus from subparts_cpus to effective_cpus */
int old_prs, new_prs;
@@ -1233,16 +1244,16 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
* The new cpumask, if present, or the current cpus_allowed must
* not be empty.
*/
- if (!is_partition_root(parent) ||
+ if (!is_partition_valid(parent) ||
(newmask && cpumask_empty(newmask)) ||
- (!newmask && cpumask_empty(cpuset->cpus_allowed)))
+ (!newmask && cpumask_empty(cs->cpus_allowed)))
return -EINVAL;
/*
* Enabling/disabling partition root is not allowed if there are
* online children.
*/
- if ((cmd != partcmd_update) && css_has_online_children(&cpuset->css))
+ if ((cmd != partcmd_update) && css_has_online_children(&cs->css))
return -EBUSY;
/*
@@ -1251,20 +1262,21 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
* CPU will be left after that.
*/
if ((cmd == partcmd_enable) &&
- (!cpumask_subset(cpuset->cpus_allowed, parent->effective_cpus) ||
- cpumask_equal(cpuset->cpus_allowed, parent->effective_cpus)))
+ (!cpumask_subset(cs->cpus_allowed, parent->effective_cpus) ||
+ cpumask_equal(cs->cpus_allowed, parent->effective_cpus)))
return -EINVAL;
/*
* A cpumask update cannot make parent's effective_cpus become empty.
+ * new_prs will only be changed for the partcmd_update command.
*/
adding = deleting = false;
- old_prs = new_prs = cpuset->partition_root_state;
+ old_prs = new_prs = cs->partition_root_state;
if (cmd == partcmd_enable) {
- cpumask_copy(tmp->addmask, cpuset->cpus_allowed);
+ cpumask_copy(tmp->addmask, cs->cpus_allowed);
adding = true;
} else if (cmd == partcmd_disable) {
- deleting = cpumask_and(tmp->delmask, cpuset->cpus_allowed,
+ deleting = cpumask_and(tmp->delmask, cs->cpus_allowed,
parent->subparts_cpus);
} else if (newmask) {
/*
@@ -1274,7 +1286,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
* addmask = newmask & parent->effective_cpus
* & ~parent->subparts_cpus
*/
- cpumask_andnot(tmp->delmask, cpuset->cpus_allowed, newmask);
+ cpumask_andnot(tmp->delmask, cs->cpus_allowed, newmask);
deleting = cpumask_and(tmp->delmask, tmp->delmask,
parent->subparts_cpus);
@@ -1308,44 +1320,44 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
* pre-shrunk in case there is a change in the cpu list.
* So no deletion is needed.
*/
- adding = cpumask_and(tmp->addmask, cpuset->cpus_allowed,
+ adding = cpumask_and(tmp->addmask, cs->cpus_allowed,
parent->effective_cpus);
part_error = cpumask_equal(tmp->addmask,
parent->effective_cpus);
}
if (cmd == partcmd_update) {
- int prev_prs = cpuset->partition_root_state;
+ int prev_prs = cs->partition_root_state;
/*
- * Check for possible transition between PRS_ENABLED
- * and PRS_ERROR.
+ * Check for possible transition between PRS_ROOT
+ * and PRS_INVALID_ROOT.
*/
- switch (cpuset->partition_root_state) {
- case PRS_ENABLED:
+ switch (cs->partition_root_state) {
+ case PRS_ROOT:
if (part_error)
- new_prs = PRS_ERROR;
+ new_prs = PRS_INVALID_ROOT;
break;
- case PRS_ERROR:
+ case PRS_INVALID_ROOT:
if (!part_error)
- new_prs = PRS_ENABLED;
+ new_prs = PRS_ROOT;
break;
}
/*
* Set part_error if previously in invalid state.
*/
- part_error = (prev_prs == PRS_ERROR);
+ part_error = is_prs_invalid(prev_prs);
}
- if (!part_error && (new_prs == PRS_ERROR))
+ if (!part_error && is_prs_invalid(new_prs))
return 0; /* Nothing need to be done */
- if (new_prs == PRS_ERROR) {
+ if (is_prs_invalid(new_prs)) {
/*
* Remove all its cpus from parent's subparts_cpus.
*/
adding = false;
- deleting = cpumask_and(tmp->delmask, cpuset->cpus_allowed,
+ deleting = cpumask_and(tmp->delmask, cs->cpus_allowed,
parent->subparts_cpus);
}
@@ -1378,10 +1390,10 @@ static int update_parent_subparts_cpumask(struct cpuset *cpuset, int cmd,
parent->nr_subparts_cpus = cpumask_weight(parent->subparts_cpus);
if (old_prs != new_prs)
- cpuset->partition_root_state = new_prs;
+ cs->partition_root_state = new_prs;
spin_unlock_irq(&callback_lock);
- notify_partition_change(cpuset, old_prs, new_prs);
+ notify_partition_change(cs, old_prs);
return cmd == partcmd_update;
}
@@ -1446,15 +1458,14 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
old_prs = new_prs = cp->partition_root_state;
if ((cp != cs) && old_prs) {
switch (parent->partition_root_state) {
- case PRS_DISABLED:
+ case PRS_MEMBER:
/*
* If parent is not a partition root or an
* invalid partition root, clear its state
* and its CS_CPU_EXCLUSIVE flag.
*/
- WARN_ON_ONCE(cp->partition_root_state
- != PRS_ERROR);
- new_prs = PRS_DISABLED;
+ WARN_ON_ONCE(!is_partition_invalid(cp));
+ new_prs = PRS_MEMBER;
/*
* clear_bit() is an atomic operation and
@@ -1466,16 +1477,16 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
clear_bit(CS_CPU_EXCLUSIVE, &cp->flags);
break;
- case PRS_ENABLED:
+ case PRS_ROOT:
if (update_parent_subparts_cpumask(cp, partcmd_update, NULL, tmp))
update_tasks_cpumask(parent);
break;
- case PRS_ERROR:
+ case PRS_INVALID_ROOT:
/*
* When parent is invalid, it has to be too.
*/
- new_prs = PRS_ERROR;
+ new_prs = PRS_INVALID_ROOT;
break;
}
}
@@ -1487,7 +1498,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
spin_lock_irq(&callback_lock);
cpumask_copy(cp->effective_cpus, tmp->new_cpus);
- if (cp->nr_subparts_cpus && (new_prs != PRS_ENABLED)) {
+ if (cp->nr_subparts_cpus && !is_partition_valid(cp)) {
cp->nr_subparts_cpus = 0;
cpumask_clear(cp->subparts_cpus);
} else if (cp->nr_subparts_cpus) {
@@ -1519,7 +1530,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
cp->partition_root_state = new_prs;
spin_unlock_irq(&callback_lock);
- notify_partition_change(cp, old_prs, new_prs);
+ notify_partition_change(cp, old_prs);
WARN_ON(!is_in_v2_mode() &&
!cpumask_equal(cp->cpus_allowed, cp->effective_cpus));
@@ -1535,7 +1546,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
if (!cpumask_empty(cp->cpus_allowed) &&
is_sched_load_balance(cp) &&
(!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) ||
- is_partition_root(cp)))
+ is_partition_valid(cp)))
need_rebuild_sched_domains = true;
rcu_read_lock();
@@ -2035,10 +2046,11 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
return err;
}
-/*
+/**
* update_prstate - update partition_root_state
- * cs: the cpuset to update
- * new_prs: new partition root state
+ * @cs: the cpuset to update
+ * @new_prs: new partition root state
+ * Return: 0 if successful, < 0 if error
*
* Call with cpuset_rwsem held.
*/
@@ -2055,7 +2067,7 @@ static int update_prstate(struct cpuset *cs, int new_prs)
* Cannot force a partial or invalid partition root to a full
* partition root.
*/
- if (new_prs && (old_prs == PRS_ERROR))
+ if (new_prs && is_prs_invalid(old_prs))
return -EINVAL;
if (alloc_cpumasks(NULL, &tmpmask))
@@ -2086,7 +2098,7 @@ static int update_prstate(struct cpuset *cs, int new_prs)
* Turning off partition root will clear the
* CS_CPU_EXCLUSIVE bit.
*/
- if (old_prs == PRS_ERROR) {
+ if (is_prs_invalid(old_prs)) {
update_flag(CS_CPU_EXCLUSIVE, cs, 0);
err = 0;
goto out;
@@ -2112,7 +2124,7 @@ static int update_prstate(struct cpuset *cs, int new_prs)
spin_lock_irq(&callback_lock);
cs->partition_root_state = new_prs;
spin_unlock_irq(&callback_lock);
- notify_partition_change(cs, old_prs, new_prs);
+ notify_partition_change(cs, old_prs);
}
free_cpumasks(NULL, &tmpmask);
@@ -2604,13 +2616,13 @@ static int sched_partition_show(struct seq_file *seq, void *v)
struct cpuset *cs = css_cs(seq_css(seq));
switch (cs->partition_root_state) {
- case PRS_ENABLED:
+ case PRS_ROOT:
seq_puts(seq, "root\n");
break;
- case PRS_DISABLED:
+ case PRS_MEMBER:
seq_puts(seq, "member\n");
break;
- case PRS_ERROR:
+ case PRS_INVALID_ROOT:
seq_puts(seq, "root invalid\n");
break;
}
@@ -2630,9 +2642,9 @@ static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf,
* Convert "root" to ENABLED, and convert "member" to DISABLED.
*/
if (!strcmp(buf, "root"))
- val = PRS_ENABLED;
+ val = PRS_ROOT;
else if (!strcmp(buf, "member"))
- val = PRS_DISABLED;
+ val = PRS_MEMBER;
else
return -EINVAL;
@@ -2931,7 +2943,7 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css)
cpus_read_lock();
percpu_down_write(&cpuset_rwsem);
- if (is_partition_root(cs))
+ if (is_partition_valid(cs))
update_prstate(cs, 0);
if (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) &&
@@ -3176,11 +3188,11 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
/*
* In the unlikely event that a partition root has empty
- * effective_cpus or its parent becomes erroneous, we have to
- * transition it to the erroneous state.
+ * effective_cpus or its parent becomes invalid, we have to
+ * transition it to the invalid state.
*/
- if (is_partition_root(cs) && (cpumask_empty(&new_cpus) ||
- (parent->partition_root_state == PRS_ERROR))) {
+ if (is_partition_valid(cs) && (cpumask_empty(&new_cpus) ||
+ is_partition_invalid(parent))) {
if (cs->nr_subparts_cpus) {
spin_lock_irq(&callback_lock);
cs->nr_subparts_cpus = 0;
@@ -3195,30 +3207,29 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
* the current partition and let the child partitions
* fight for available CPUs.
*/
- if ((parent->partition_root_state == PRS_ERROR) ||
+ if (is_partition_invalid(parent) ||
cpumask_empty(&new_cpus)) {
int old_prs;
update_parent_subparts_cpumask(cs, partcmd_disable,
NULL, tmp);
old_prs = cs->partition_root_state;
- if (old_prs != PRS_ERROR) {
+ if (!is_prs_invalid(old_prs)) {
spin_lock_irq(&callback_lock);
- cs->partition_root_state = PRS_ERROR;
+ make_partition_invalid(cs);
spin_unlock_irq(&callback_lock);
- notify_partition_change(cs, old_prs, PRS_ERROR);
+ notify_partition_change(cs, old_prs);
}
}
cpuset_force_rebuild();
}
/*
- * On the other hand, an erroneous partition root may be transitioned
+ * On the other hand, an invalid partition root may be transitioned
* back to a regular one or a partition root with no CPU allocated
- * from the parent may change to erroneous.
+ * from the parent may change to invalid.
*/
- if (is_partition_root(parent) &&
- ((cs->partition_root_state == PRS_ERROR) ||
+ if (is_partition_valid(parent) && (is_partition_invalid(cs) ||
!cpumask_intersects(&new_cpus, parent->subparts_cpus)) &&
update_parent_subparts_cpumask(cs, partcmd_update, NULL, tmp))
cpuset_force_rebuild();
From e2d59900d936e1c0fe091216c342cc95c4b32e97 Mon Sep 17 00:00:00 2001
From: Waiman Long <longman@redhat.com>
Date: Thu, 1 Sep 2022 16:57:38 -0400
Subject: [PATCH 11/25] cgroup/cpuset: Allow no-task partition to have empty
cpuset.cpus.effective
Currently, a partition root cannot have empty "cpuset.cpus.effective".
As a result, a parent partition root cannot distribute out all its
CPUs to child partitions with no CPUs left. However in most cases,
there shouldn't be any tasks associated with intermediate nodes of the
default hierarchy. So the current rule is too restrictive and can waste
valuable CPU resource.
To address this issue, we are now allowing a partition to have empty
"cpuset.cpus.effective" as long as it has no task. Since cpuset is
threaded, no-internal-process rule does not apply. So it is possible
to have tasks in a partition root with child sub-partitions even though
that should be uncommon.
A parent partition with no task can now have all its CPUs distributed out
to its child partitions. The top cpuset always have some house-keeping
tasks running and so its list of effective cpu can't be empty.
Once a partition with empty "cpuset.cpus.effective" is formed, no
new task can be moved into it until "cpuset.cpus.effective" becomes
non-empty.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/cpuset.c | 109 +++++++++++++++++++++++++++++++----------
1 file changed, 84 insertions(+), 25 deletions(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 68404e4885040..cdde9ef05ad20 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -416,6 +416,41 @@ static inline bool is_in_v2_mode(void)
(cpuset_cgrp_subsys.root->flags & CGRP_ROOT_CPUSET_V2_MODE);
}
+/**
+ * partition_is_populated - check if partition has tasks
+ * @cs: partition root to be checked
+ * @excluded_child: a child cpuset to be excluded in task checking
+ * Return: true if there are tasks, false otherwise
+ *
+ * It is assumed that @cs is a valid partition root. @excluded_child should
+ * be non-NULL when this cpuset is going to become a partition itself.
+ */
+static inline bool partition_is_populated(struct cpuset *cs,
+ struct cpuset *excluded_child)
+{
+ struct cgroup_subsys_state *css;
+ struct cpuset *child;
+
+ if (cs->css.cgroup->nr_populated_csets)
+ return true;
+ if (!excluded_child && !cs->nr_subparts_cpus)
+ return cgroup_is_populated(cs->css.cgroup);
+
+ rcu_read_lock();
+ cpuset_for_each_child(child, css, cs) {
+ if (child == excluded_child)
+ continue;
+ if (is_partition_valid(child))
+ continue;
+ if (cgroup_is_populated(child->css.cgroup)) {
+ rcu_read_unlock();
+ return true;
+ }
+ }
+ rcu_read_unlock();
+ return false;
+}
+
/*
* Return in pmask the portion of a task's cpusets's cpus_allowed that
* are online and are capable of running the task. If none are found,
@@ -1257,22 +1292,27 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
return -EBUSY;
/*
- * Enabling partition root is not allowed if not all the CPUs
- * can be granted from parent's effective_cpus or at least one
- * CPU will be left after that.
- */
- if ((cmd == partcmd_enable) &&
- (!cpumask_subset(cs->cpus_allowed, parent->effective_cpus) ||
- cpumask_equal(cs->cpus_allowed, parent->effective_cpus)))
- return -EINVAL;
-
- /*
- * A cpumask update cannot make parent's effective_cpus become empty.
* new_prs will only be changed for the partcmd_update command.
*/
adding = deleting = false;
old_prs = new_prs = cs->partition_root_state;
if (cmd == partcmd_enable) {
+ /*
+ * Enabling partition root is not allowed if not all the CPUs
+ * can be granted from parent's effective_cpus.
+ */
+ if (!cpumask_subset(cs->cpus_allowed, parent->effective_cpus))
+ return -EINVAL;
+
+ /*
+ * A parent can be left with no CPU as long as there is no
+ * task directly associated with the parent partition. For
+ * such a parent, no new task can be moved into it.
+ */
+ if (cpumask_equal(cs->cpus_allowed, parent->effective_cpus) &&
+ partition_is_populated(parent, cs))
+ return -EINVAL;
+
cpumask_copy(tmp->addmask, cs->cpus_allowed);
adding = true;
} else if (cmd == partcmd_disable) {
@@ -1294,10 +1334,12 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
adding = cpumask_andnot(tmp->addmask, tmp->addmask,
parent->subparts_cpus);
/*
- * Return error if the new effective_cpus could become empty.
+ * Return error if the new effective_cpus could become empty
+ * and there are tasks in the parent.
*/
if (adding &&
- cpumask_equal(parent->effective_cpus, tmp->addmask)) {
+ cpumask_equal(parent->effective_cpus, tmp->addmask) &&
+ partition_is_populated(parent, cs)) {
if (!deleting)
return -EINVAL;
/*
@@ -1322,8 +1364,8 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
*/
adding = cpumask_and(tmp->addmask, cs->cpus_allowed,
parent->effective_cpus);
- part_error = cpumask_equal(tmp->addmask,
- parent->effective_cpus);
+ part_error = cpumask_equal(tmp->addmask, parent->effective_cpus) &&
+ partition_is_populated(parent, cs);
}
if (cmd == partcmd_update) {
@@ -1425,9 +1467,15 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
/*
* If it becomes empty, inherit the effective mask of the
- * parent, which is guaranteed to have some CPUs.
+ * parent, which is guaranteed to have some CPUs unless
+ * it is a partition root that has explicitly distributed
+ * out all its CPUs.
*/
if (is_in_v2_mode() && cpumask_empty(tmp->new_cpus)) {
+ if (is_partition_valid(cp) &&
+ cpumask_equal(cp->cpus_allowed, cp->subparts_cpus))
+ goto update_parent_subparts;
+
cpumask_copy(tmp->new_cpus, parent->effective_cpus);
if (!cp->use_parent_ecpus) {
cp->use_parent_ecpus = true;
@@ -1449,6 +1497,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
continue;
}
+update_parent_subparts:
/*
* update_parent_subparts_cpumask() should have been called
* for cs already in update_cpumask(). We should also call
@@ -2254,6 +2303,12 @@ static int cpuset_can_attach(struct cgroup_taskset *tset)
(cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed)))
goto out_unlock;
+ /*
+ * Task cannot be moved to a cpuset with empty effective cpus.
+ */
+ if (cpumask_empty(cs->effective_cpus))
+ goto out_unlock;
+
cgroup_taskset_for_each(task, css, tset) {
ret = task_can_attach(task, cs->effective_cpus);
if (ret)
@@ -3119,7 +3174,8 @@ hotplug_update_tasks(struct cpuset *cs,
struct cpumask *new_cpus, nodemask_t *new_mems,
bool cpus_updated, bool mems_updated)
{
- if (cpumask_empty(new_cpus))
+ /* A partition root is allowed to have empty effective cpus */
+ if (cpumask_empty(new_cpus) && !is_partition_valid(cs))
cpumask_copy(new_cpus, parent_cs(cs)->effective_cpus);
if (nodes_empty(*new_mems))
*new_mems = parent_cs(cs)->effective_mems;
@@ -3188,10 +3244,11 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
/*
* In the unlikely event that a partition root has empty
- * effective_cpus or its parent becomes invalid, we have to
- * transition it to the invalid state.
+ * effective_cpus with tasks or its parent becomes invalid, we
+ * have to transition it to the invalid state.
*/
- if (is_partition_valid(cs) && (cpumask_empty(&new_cpus) ||
+ if (is_partition_valid(cs) &&
+ ((cpumask_empty(&new_cpus) && partition_is_populated(cs, NULL)) ||
is_partition_invalid(parent))) {
if (cs->nr_subparts_cpus) {
spin_lock_irq(&callback_lock);
@@ -3202,13 +3259,15 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
}
/*
- * If the effective_cpus is empty because the child
- * partitions take away all the CPUs, we can keep
- * the current partition and let the child partitions
- * fight for available CPUs.
+ * Force the partition to become invalid if either one of
+ * the following conditions hold:
+ * 1) empty effective cpus but not valid empty partition.
+ * 2) parent is invalid or doesn't grant any cpus to child
+ * partitions.
*/
if (is_partition_invalid(parent) ||
- cpumask_empty(&new_cpus)) {
+ (cpumask_empty(&new_cpus) &&
+ partition_is_populated(cs, NULL))) {
int old_prs;
update_parent_subparts_cpumask(cs, partcmd_disable,
From f0af1bfc27b52a4d42510051154c61bd176a8f06 Mon Sep 17 00:00:00 2001
From: Waiman Long <longman@redhat.com>
Date: Thu, 1 Sep 2022 16:57:39 -0400
Subject: [PATCH 12/25] cgroup/cpuset: Relax constraints to partition & cpus
changes
Currently, enabling a partition root is only allowed if all the
constraints of a valid partition are satisfied. Even changes to
"cpuset.cpus" may not be allowed in some cases. Moreover, there are
limits to changes made to a parent cpuset if it is a valid partition
root. This is contrary to the general cgroup v2 philosophy.
This patch relaxes the constraints of changing the state of "cpuset.cpus"
and "cpuset.cpus.partition". Now all valid changes ("member" or "root")
to "cpuset.cpus.partition" are allowed even if there are child cpusets
underneath it.
Trying to make a cpuset a partition root, however, will cause its state
to become invalid if the following constraints of a valid partition
root are not satisfied.
1) The "cpuset.cpus" is non-empty and exclusive.
2) The parent cpuset is a valid partition root.
3) The "cpuset.cpus" overlaps parent's "cpuset.cpus".
Similarly, almost all changes to "cpuset.cpus" are allowed with the
exception that if the underlying CS_CPU_EXCLUSIVE flag is set, the
exclusivity rule will still apply.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/cpuset.c | 409 ++++++++++++++++++++++-------------------
1 file changed, 215 insertions(+), 194 deletions(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index cdde9ef05ad20..7f64bb1a7befa 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1222,13 +1222,15 @@ enum subparts_cmd {
partcmd_update, /* Update parent's subparts_cpus */
};
+static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
+ int turning_on);
/**
* update_parent_subparts_cpumask - update subparts_cpus mask of parent cpuset
* @cpuset: The cpuset that requests change in partition root state
* @cmd: Partition root state change command
* @newmask: Optional new cpumask for partcmd_update
* @tmp: Temporary addmask and delmask
- * Return: 0, 1 or an error code
+ * Return: 0 or -1 (error)
*
* For partcmd_enable, the cpuset is being transformed from a non-partition
* root to a partition root. The cpus_allowed mask of the given cpuset will
@@ -1239,28 +1241,22 @@ enum subparts_cmd {
* For partcmd_disable, the cpuset is being transformed from a partition
* root back to a non-partition root. Any CPUs in cpus_allowed that are in
* parent's subparts_cpus will be taken away from that cpumask and put back
- * into parent's effective_cpus. 0 should always be returned.
+ * into parent's effective_cpus. 0 will always be returned.
*
- * For partcmd_update, if the optional newmask is specified, the cpu
- * list is to be changed from cpus_allowed to newmask. Otherwise,
- * cpus_allowed is assumed to remain the same. The cpuset should either
- * be a partition root or an invalid partition root. The partition root
- * state may change if newmask is NULL and none of the requested CPUs can
- * be granted by the parent. The function will return 1 if changes to
- * parent's subparts_cpus and effective_cpus happen or 0 otherwise.
- * Error code should only be returned when newmask is non-NULL.
+ * For partcmd_update, if the optional newmask is specified, the cpu list is
+ * to be changed from cpus_allowed to newmask. Otherwise, cpus_allowed is
+ * assumed to remain the same. The cpuset should either be a valid or invalid
+ * partition root. The partition root state may change from valid to invalid
+ * or vice versa. An error code will only be returned if transitioning from
+ * invalid to valid violates the exclusivity rule.
*
* The partcmd_enable and partcmd_disable commands are used by
- * update_prstate(). The partcmd_update command is used by
- * update_cpumasks_hier() with newmask NULL and update_cpumask() with
- * newmask set.
- *
- * The checking is more strict when enabling partition root than the
- * other two commands.
+ * update_prstate(). An error code may be returned and the caller will check
+ * for error.
*
- * Because of the implicit cpu exclusive nature of a partition root,
- * cpumask changes that violates the cpu exclusivity rule will not be
- * permitted when checked by validate_change().
+ * The partcmd_update command is used by update_cpumasks_hier() with newmask
+ * NULL and update_cpumask() with newmask set. The callers won't check for
+ * error and so partition_root_state will be updated directly.
*/
static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
struct cpumask *newmask,
@@ -1282,14 +1278,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
if (!is_partition_valid(parent) ||
(newmask && cpumask_empty(newmask)) ||
(!newmask && cpumask_empty(cs->cpus_allowed)))
- return -EINVAL;
-
- /*
- * Enabling/disabling partition root is not allowed if there are
- * online children.
- */
- if ((cmd != partcmd_update) && css_has_online_children(&cs->css))
- return -EBUSY;
+ return -1;
/*
* new_prs will only be changed for the partcmd_update command.
@@ -1298,79 +1287,98 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
old_prs = new_prs = cs->partition_root_state;
if (cmd == partcmd_enable) {
/*
- * Enabling partition root is not allowed if not all the CPUs
- * can be granted from parent's effective_cpus.
+ * Enabling partition root is not allowed if cpus_allowed
+ * doesn't overlap parent's cpus_allowed.
*/
- if (!cpumask_subset(cs->cpus_allowed, parent->effective_cpus))
- return -EINVAL;
+ if (!cpumask_intersects(cs->cpus_allowed, parent->cpus_allowed))
+ return -1;
/*
* A parent can be left with no CPU as long as there is no
- * task directly associated with the parent partition. For
- * such a parent, no new task can be moved into it.
+ * task directly associated with the parent partition.
*/
- if (cpumask_equal(cs->cpus_allowed, parent->effective_cpus) &&
+ if (!cpumask_intersects(cs->cpus_allowed, parent->effective_cpus) &&
partition_is_populated(parent, cs))
- return -EINVAL;
+ return -1;
cpumask_copy(tmp->addmask, cs->cpus_allowed);
adding = true;
} else if (cmd == partcmd_disable) {
- deleting = cpumask_and(tmp->delmask, cs->cpus_allowed,
+ /*
+ * Need to remove cpus from parent's subparts_cpus for valid
+ * partition root.
+ */
+ deleting = !is_prs_invalid(old_prs) &&
+ cpumask_and(tmp->delmask, cs->cpus_allowed,
parent->subparts_cpus);
} else if (newmask) {
/*
* partcmd_update with newmask:
*
+ * Compute add/delete mask to/from subparts_cpus
+ *
* delmask = cpus_allowed & ~newmask & parent->subparts_cpus
- * addmask = newmask & parent->effective_cpus
+ * addmask = newmask & parent->cpus_allowed
* & ~parent->subparts_cpus
*/
cpumask_andnot(tmp->delmask, cs->cpus_allowed, newmask);
deleting = cpumask_and(tmp->delmask, tmp->delmask,
parent->subparts_cpus);
- cpumask_and(tmp->addmask, newmask, parent->effective_cpus);
+ cpumask_and(tmp->addmask, newmask, parent->cpus_allowed);
adding = cpumask_andnot(tmp->addmask, tmp->addmask,
parent->subparts_cpus);
/*
- * Return error if the new effective_cpus could become empty
- * and there are tasks in the parent.
+ * Make partition invalid if parent's effective_cpus could
+ * become empty and there are tasks in the parent.
*/
if (adding &&
- cpumask_equal(parent->effective_cpus, tmp->addmask) &&
+ cpumask_subset(parent->effective_cpus, tmp->addmask) &&
+ !cpumask_intersects(tmp->delmask, cpu_active_mask) &&
partition_is_populated(parent, cs)) {
- if (!deleting)
- return -EINVAL;
- /*
- * As some of the CPUs in subparts_cpus might have
- * been offlined, we need to compute the real delmask
- * to confirm that.
- */
- if (!cpumask_and(tmp->addmask, tmp->delmask,
- cpu_active_mask))
- return -EINVAL;
- cpumask_copy(tmp->addmask, parent->effective_cpus);
+ part_error = true;
+ adding = false;
+ deleting = cpumask_and(tmp->delmask, cs->cpus_allowed,
+ parent->subparts_cpus);
}
} else {
/*
* partcmd_update w/o newmask:
*
- * addmask = cpus_allowed & parent->effective_cpus
+ * delmask = cpus_allowed & parent->subparts_cpus
+ * addmask = cpus_allowed & parent->cpus_allowed
+ * & ~parent->subparts_cpus
*
- * Note that parent's subparts_cpus may have been
- * pre-shrunk in case there is a change in the cpu list.
- * So no deletion is needed.
+ * This gets invoked either due to a hotplug event or from
+ * update_cpumasks_hier(). This can cause the state of a
+ * partition root to transition from valid to invalid or vice
+ * versa. So we still need to compute the addmask and delmask.
+
+ * A partition error happens when:
+ * 1) Cpuset is valid partition, but parent does not distribute
+ * out any CPUs.
+ * 2) Parent has tasks and all its effective CPUs will have
+ * to be distributed out.
*/
- adding = cpumask_and(tmp->addmask, cs->cpus_allowed,
- parent->effective_cpus);
- part_error = cpumask_equal(tmp->addmask, parent->effective_cpus) &&
- partition_is_populated(parent, cs);
+ cpumask_and(tmp->addmask, cs->cpus_allowed,
+ parent->cpus_allowed);
+ adding = cpumask_andnot(tmp->addmask, tmp->addmask,
+ parent->subparts_cpus);
+ if ((is_partition_valid(cs) && !parent->nr_subparts_cpus) ||
+ (adding &&
+ cpumask_subset(parent->effective_cpus, tmp->addmask) &&
+ partition_is_populated(parent, cs))) {
+ part_error = true;
+ adding = false;
+ }
+
+ if (part_error && is_partition_valid(cs) &&
+ parent->nr_subparts_cpus)
+ deleting = cpumask_and(tmp->delmask, cs->cpus_allowed,
+ parent->subparts_cpus);
}
if (cmd == partcmd_update) {
- int prev_prs = cs->partition_root_state;
-
/*
* Check for possible transition between PRS_ROOT
* and PRS_INVALID_ROOT.
@@ -1385,27 +1393,23 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
new_prs = PRS_ROOT;
break;
}
- /*
- * Set part_error if previously in invalid state.
- */
- part_error = is_prs_invalid(prev_prs);
- }
-
- if (!part_error && is_prs_invalid(new_prs))
- return 0; /* Nothing need to be done */
-
- if (is_prs_invalid(new_prs)) {
- /*
- * Remove all its cpus from parent's subparts_cpus.
- */
- adding = false;
- deleting = cpumask_and(tmp->delmask, cs->cpus_allowed,
- parent->subparts_cpus);
}
if (!adding && !deleting && (new_prs == old_prs))
return 0;
+ /*
+ * Transitioning between invalid to valid or vice versa may require
+ * changing CS_CPU_EXCLUSIVE.
+ */
+ if (old_prs != new_prs) {
+ if (is_prs_invalid(old_prs) && !is_cpu_exclusive(cs) &&
+ (update_flag(CS_CPU_EXCLUSIVE, cs, 1) < 0))
+ return -1;
+ if (is_prs_invalid(new_prs) && is_cpu_exclusive(cs))
+ update_flag(CS_CPU_EXCLUSIVE, cs, 0);
+ }
+
/*
* Change the parent's subparts_cpus.
* Newly added CPUs will be removed from effective_cpus and
@@ -1435,15 +1439,20 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
cs->partition_root_state = new_prs;
spin_unlock_irq(&callback_lock);
+
+ if (adding || deleting)
+ update_tasks_cpumask(parent);
+
notify_partition_change(cs, old_prs);
- return cmd == partcmd_update;
+ return 0;
}
/*
* update_cpumasks_hier - Update effective cpumasks and tasks in the subtree
* @cs: the cpuset to consider
* @tmp: temp variables for calculating effective_cpus & partition setup
+ * @force: don't skip any descendant cpusets if set
*
* When configured cpumask is changed, the effective cpumasks of this cpuset
* and all its descendants need to be updated.
@@ -1452,7 +1461,8 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
*
* Called with cpuset_rwsem held
*/
-static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
+static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp,
+ bool force)
{
struct cpuset *cp;
struct cgroup_subsys_state *pos_css;
@@ -1462,6 +1472,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
rcu_read_lock();
cpuset_for_each_descendant_pre(cp, pos_css, cs) {
struct cpuset *parent = parent_cs(cp);
+ bool update_parent = false;
compute_effective_cpumask(tmp->new_cpus, cp, parent);
@@ -1489,9 +1500,9 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
/*
* Skip the whole subtree if the cpumask remains the same
- * and has no partition root state.
+ * and has no partition root state and force flag not set.
*/
- if (!cp->partition_root_state &&
+ if (!cp->partition_root_state && !force &&
cpumask_equal(tmp->new_cpus, cp->effective_cpus)) {
pos_css = css_rightmost_descendant(pos_css);
continue;
@@ -1507,33 +1518,15 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
old_prs = new_prs = cp->partition_root_state;
if ((cp != cs) && old_prs) {
switch (parent->partition_root_state) {
- case PRS_MEMBER:
- /*
- * If parent is not a partition root or an
- * invalid partition root, clear its state
- * and its CS_CPU_EXCLUSIVE flag.
- */
- WARN_ON_ONCE(!is_partition_invalid(cp));
- new_prs = PRS_MEMBER;
-
- /*
- * clear_bit() is an atomic operation and
- * readers aren't interested in the state
- * of CS_CPU_EXCLUSIVE anyway. So we can
- * just update the flag without holding
- * the callback_lock.
- */
- clear_bit(CS_CPU_EXCLUSIVE, &cp->flags);
- break;
-
case PRS_ROOT:
- if (update_parent_subparts_cpumask(cp, partcmd_update, NULL, tmp))
- update_tasks_cpumask(parent);
+ update_parent = true;
break;
- case PRS_INVALID_ROOT:
+ default:
/*
- * When parent is invalid, it has to be too.
+ * When parent is not a partition root or is
+ * invalid, child partition roots become
+ * invalid too.
*/
new_prs = PRS_INVALID_ROOT;
break;
@@ -1544,41 +1537,43 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp)
continue;
rcu_read_unlock();
+ if (update_parent) {
+ update_parent_subparts_cpumask(cp, partcmd_update, NULL,
+ tmp);
+ /*
+ * The cpuset partition_root_state may become
+ * invalid. Capture it.
+ */
+ new_prs = cp->partition_root_state;
+ }
+
spin_lock_irq(&callback_lock);
- cpumask_copy(cp->effective_cpus, tmp->new_cpus);
if (cp->nr_subparts_cpus && !is_partition_valid(cp)) {
+ /*
+ * Put all active subparts_cpus back to effective_cpus.
+ */
+ cpumask_or(tmp->new_cpus, tmp->new_cpus,
+ cp->subparts_cpus);
+ cpumask_and(tmp->new_cpus, tmp->new_cpus,
+ cpu_active_mask);
cp->nr_subparts_cpus = 0;
cpumask_clear(cp->subparts_cpus);
- } else if (cp->nr_subparts_cpus) {
+ }
+
+ cpumask_copy(cp->effective_cpus, tmp->new_cpus);
+ if (cp->nr_subparts_cpus) {
/*
* Make sure that effective_cpus & subparts_cpus
* are mutually exclusive.
- *
- * In the unlikely event that effective_cpus
- * becomes empty. we clear cp->nr_subparts_cpus and
- * let its child partition roots to compete for
- * CPUs again.
*/
cpumask_andnot(cp->effective_cpus, cp->effective_cpus,
cp->subparts_cpus);
- if (cpumask_empty(cp->effective_cpus)) {
- cpumask_copy(cp->effective_cpus, tmp->new_cpus);
- cpumask_clear(cp->subparts_cpus);
- cp->nr_subparts_cpus = 0;
- } else if (!cpumask_subset(cp->subparts_cpus,
- tmp->new_cpus)) {
- cpumask_andnot(cp->subparts_cpus,
- cp->subparts_cpus, tmp->new_cpus);
- cp->nr_subparts_cpus
- = cpumask_weight(cp->subparts_cpus);
- }
}
- if (new_prs != old_prs)
- cp->partition_root_state = new_prs;
-
+ cp->partition_root_state = new_prs;
spin_unlock_irq(&callback_lock);
+
notify_partition_change(cp, old_prs);
WARN_ON(!is_in_v2_mode() &&
@@ -1639,7 +1634,7 @@ static void update_sibling_cpumasks(struct cpuset *parent, struct cpuset *cs,
continue;
rcu_read_unlock();
- update_cpumasks_hier(sibling, tmp);
+ update_cpumasks_hier(sibling, tmp, false);
rcu_read_lock();
css_put(&sibling->css);
}
@@ -1699,27 +1694,36 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
#endif
if (cs->partition_root_state) {
- /* Cpumask of a partition root cannot be empty */
- if (cpumask_empty(trialcs->cpus_allowed))
- return -EINVAL;
- if (update_parent_subparts_cpumask(cs, partcmd_update,
- trialcs->cpus_allowed, &tmp) < 0)
- return -EINVAL;
+ update_parent_subparts_cpumask(cs, partcmd_update,
+ trialcs->cpus_allowed, &tmp);
}
+ compute_effective_cpumask(trialcs->effective_cpus, trialcs,
+ parent_cs(cs));
spin_lock_irq(&callback_lock);
cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed);
/*
- * Make sure that subparts_cpus is a subset of cpus_allowed.
+ * Make sure that subparts_cpus, if not empty, is a subset of
+ * cpus_allowed. Clear subparts_cpus if partition not valid or
+ * empty effective cpus with tasks.
*/
if (cs->nr_subparts_cpus) {
- cpumask_and(cs->subparts_cpus, cs->subparts_cpus, cs->cpus_allowed);
- cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus);
+ if (!is_partition_valid(cs) ||
+ (cpumask_subset(trialcs->effective_cpus, cs->subparts_cpus) &&
+ partition_is_populated(cs, NULL))) {
+ cs->nr_subparts_cpus = 0;
+ cpumask_clear(cs->subparts_cpus);
+ } else {
+ cpumask_and(cs->subparts_cpus, cs->subparts_cpus,
+ cs->cpus_allowed);
+ cs->nr_subparts_cpus = cpumask_weight(cs->subparts_cpus);
+ }
}
spin_unlock_irq(&callback_lock);
- update_cpumasks_hier(cs, &tmp);
+ /* effective_cpus will be updated here */
+ update_cpumasks_hier(cs, &tmp, false);
if (cs->partition_root_state) {
struct cpuset *parent = parent_cs(cs);
@@ -2105,7 +2109,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
*/
static int update_prstate(struct cpuset *cs, int new_prs)
{
- int err, old_prs = cs->partition_root_state;
+ int err = 0, old_prs = cs->partition_root_state;
struct cpuset *parent = parent_cs(cs);
struct tmpmasks tmpmask;
@@ -2113,24 +2117,25 @@ static int update_prstate(struct cpuset *cs, int new_prs)
return 0;
/*
- * Cannot force a partial or invalid partition root to a full
- * partition root.
+ * For a previously invalid partition root, leave it at being
+ * invalid if new_prs is not "member".
*/
if (new_prs && is_prs_invalid(old_prs))
- return -EINVAL;
+ return 0;
if (alloc_cpumasks(NULL, &tmpmask))
return -ENOMEM;
- err = -EINVAL;
if (!old_prs) {
/*
* Turning on partition root requires setting the
* CS_CPU_EXCLUSIVE bit implicitly as well and cpus_allowed
- * cannot be NULL.
+ * cannot be empty.
*/
- if (cpumask_empty(cs->cpus_allowed))
+ if (cpumask_empty(cs->cpus_allowed)) {
+ err = 1;
goto out;
+ }
err = update_flag(CS_CPU_EXCLUSIVE, cs, 1);
if (err)
@@ -2144,19 +2149,22 @@ static int update_prstate(struct cpuset *cs, int new_prs)
}
} else {
/*
- * Turning off partition root will clear the
- * CS_CPU_EXCLUSIVE bit.
+ * Switching back to member is always allowed even if it
+ * disables child partitions.
*/
- if (is_prs_invalid(old_prs)) {
- update_flag(CS_CPU_EXCLUSIVE, cs, 0);
- err = 0;
- goto out;
- }
+ update_parent_subparts_cpumask(cs, partcmd_disable, NULL,
+ &tmpmask);
- err = update_parent_subparts_cpumask(cs, partcmd_disable,
- NULL, &tmpmask);
- if (err)
- goto out;
+ /*
+ * If there are child partitions, they will all become invalid.
+ */
+ if (unlikely(cs->nr_subparts_cpus)) {
+ spin_lock_irq(&callback_lock);
+ cs->nr_subparts_cpus = 0;
+ cpumask_clear(cs->subparts_cpus);
+ compute_effective_cpumask(cs->effective_cpus, cs, parent);
+ spin_unlock_irq(&callback_lock);
+ }
/* Turning off CS_CPU_EXCLUSIVE will not return error */
update_flag(CS_CPU_EXCLUSIVE, cs, 0);
@@ -2169,15 +2177,24 @@ static int update_prstate(struct cpuset *cs, int new_prs)
rebuild_sched_domains_locked();
out:
- if (!err) {
- spin_lock_irq(&callback_lock);
- cs->partition_root_state = new_prs;
- spin_unlock_irq(&callback_lock);
- notify_partition_change(cs, old_prs);
- }
+ /*
+ * Make partition invalid if an error happen
+ */
+ if (err)
+ new_prs = PRS_INVALID_ROOT;
+ spin_lock_irq(&callback_lock);
+ cs->partition_root_state = new_prs;
+ spin_unlock_irq(&callback_lock);
+ /*
+ * Update child cpusets, if present.
+ * Force update if switching back to member.
+ */
+ if (!list_empty(&cs->css.children))
+ update_cpumasks_hier(cs, &tmpmask, !new_prs);
+ notify_partition_change(cs, old_prs);
free_cpumasks(NULL, &tmpmask);
- return err;
+ return 0;
}
/*
@@ -3244,12 +3261,31 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
/*
* In the unlikely event that a partition root has empty
- * effective_cpus with tasks or its parent becomes invalid, we
- * have to transition it to the invalid state.
+ * effective_cpus with tasks, we will have to invalidate child
+ * partitions, if present, by setting nr_subparts_cpus to 0 to
+ * reclaim their cpus.
*/
- if (is_partition_valid(cs) &&
- ((cpumask_empty(&new_cpus) && partition_is_populated(cs, NULL)) ||
- is_partition_invalid(parent))) {
+ if (cs->nr_subparts_cpus && is_partition_valid(cs) &&
+ cpumask_empty(&new_cpus) && partition_is_populated(cs, NULL)) {
+ spin_lock_irq(&callback_lock);
+ cs->nr_subparts_cpus = 0;
+ cpumask_clear(cs->subparts_cpus);
+ spin_unlock_irq(&callback_lock);
+ compute_effective_cpumask(&new_cpus, cs, parent);
+ }
+
+ /*
+ * Force the partition to become invalid if either one of
+ * the following conditions hold:
+ * 1) empty effective cpus but not valid empty partition.
+ * 2) parent is invalid or doesn't grant any cpus to child
+ * partitions.
+ */
+ if (is_partition_valid(cs) && (!parent->nr_subparts_cpus ||
+ (cpumask_empty(&new_cpus) && partition_is_populated(cs, NULL)))) {
+ int old_prs;
+
+ update_parent_subparts_cpumask(cs, partcmd_disable, NULL, tmp);
if (cs->nr_subparts_cpus) {
spin_lock_irq(&callback_lock);
cs->nr_subparts_cpus = 0;
@@ -3258,40 +3294,25 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
compute_effective_cpumask(&new_cpus, cs, parent);
}
- /*
- * Force the partition to become invalid if either one of
- * the following conditions hold:
- * 1) empty effective cpus but not valid empty partition.
- * 2) parent is invalid or doesn't grant any cpus to child
- * partitions.
- */
- if (is_partition_invalid(parent) ||
- (cpumask_empty(&new_cpus) &&
- partition_is_populated(cs, NULL))) {
- int old_prs;
-
- update_parent_subparts_cpumask(cs, partcmd_disable,
- NULL, tmp);
- old_prs = cs->partition_root_state;
- if (!is_prs_invalid(old_prs)) {
- spin_lock_irq(&callback_lock);
- make_partition_invalid(cs);
- spin_unlock_irq(&callback_lock);
- notify_partition_change(cs, old_prs);
- }
+ old_prs = cs->partition_root_state;
+ if (is_partition_valid(cs)) {
+ spin_lock_irq(&callback_lock);
+ make_partition_invalid(cs);
+ spin_unlock_irq(&callback_lock);
+ notify_partition_change(cs, old_prs);
}
cpuset_force_rebuild();
}
/*
* On the other hand, an invalid partition root may be transitioned
- * back to a regular one or a partition root with no CPU allocated
- * from the parent may change to invalid.
+ * back to a regular one.
*/
- if (is_partition_valid(parent) && (is_partition_invalid(cs) ||
- !cpumask_intersects(&new_cpus, parent->subparts_cpus)) &&
- update_parent_subparts_cpumask(cs, partcmd_update, NULL, tmp))
- cpuset_force_rebuild();
+ else if (is_partition_valid(parent) && is_partition_invalid(cs)) {
+ update_parent_subparts_cpumask(cs, partcmd_update, NULL, tmp);
+ if (is_partition_valid(cs))
+ cpuset_force_rebuild();
+ }
update_tasks:
cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus);
From f28e22441f353aa2c954a1b1e29144f8841f1e8a Mon Sep 17 00:00:00 2001
From: Waiman Long <longman@redhat.com>
Date: Thu, 1 Sep 2022 16:57:40 -0400
Subject: [PATCH 13/25] cgroup/cpuset: Add a new isolated cpus.partition type
Cpuset v1 uses the sched_load_balance control file to determine if load
balancing should be enabled. Cpuset v2 gets rid of sched_load_balance
as its use may require disabling load balancing at cgroup root.
For workloads that require very low latency like DPDK, the latency
jitters caused by periodic load balancing may exceed the desired
latency limit.
When cpuset v2 is in use, the only way to avoid this latency cost is to
use the "isolcpus=" kernel boot option to isolate a set of CPUs. After
the kernel boot, however, there is no way to add or remove CPUs from
this isolated set. For workloads that are more dynamic in nature, that
means users have to provision enough CPUs for the worst case situation
resulting in excess idle CPUs.
To address this issue for cpuset v2, a new cpuset.cpus.partition type
"isolated" is added which allows the creation of a cpuset partition
without load balancing. This will allow system administrators to
dynamically adjust the size of isolated partition to the current need
of the workload without rebooting the system.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/cpuset.c | 74 +++++++++++++++++++++++++++++++++++-------
1 file changed, 63 insertions(+), 11 deletions(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 7f64bb1a7befa..f53ca022549c7 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -178,11 +178,15 @@ struct cpuset {
*
* 0 - member (not a partition root)
* 1 - partition root
+ * 2 - partition root without load balancing (isolated)
* -1 - invalid partition root
+ * -2 - invalid isolated partition root
*/
#define PRS_MEMBER 0
#define PRS_ROOT 1
+#define PRS_ISOLATED 2
#define PRS_INVALID_ROOT -1
+#define PRS_INVALID_ISOLATED -2
static inline bool is_prs_invalid(int prs_state)
{
@@ -282,7 +286,8 @@ static inline int is_partition_invalid(const struct cpuset *cs)
*/
static inline void make_partition_invalid(struct cpuset *cs)
{
- cs->partition_root_state = PRS_INVALID_ROOT;
+ if (is_partition_valid(cs))
+ cs->partition_root_state = -cs->partition_root_state;
}
/*
@@ -1380,17 +1385,19 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
if (cmd == partcmd_update) {
/*
- * Check for possible transition between PRS_ROOT
- * and PRS_INVALID_ROOT.
+ * Check for possible transition between valid and invalid
+ * partition root.
*/
switch (cs->partition_root_state) {
case PRS_ROOT:
+ case PRS_ISOLATED:
if (part_error)
- new_prs = PRS_INVALID_ROOT;
+ new_prs = -old_prs;
break;
case PRS_INVALID_ROOT:
+ case PRS_INVALID_ISOLATED:
if (!part_error)
- new_prs = PRS_ROOT;
+ new_prs = -old_prs;
break;
}
}
@@ -1400,7 +1407,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
/*
* Transitioning between invalid to valid or vice versa may require
- * changing CS_CPU_EXCLUSIVE.
+ * changing CS_CPU_EXCLUSIVE and CS_SCHED_LOAD_BALANCE.
*/
if (old_prs != new_prs) {
if (is_prs_invalid(old_prs) && !is_cpu_exclusive(cs) &&
@@ -1443,8 +1450,17 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
if (adding || deleting)
update_tasks_cpumask(parent);
+ /*
+ * Set or clear CS_SCHED_LOAD_BALANCE when partcmd_update, if necessary.
+ * rebuild_sched_domains_locked() may be called.
+ */
+ if (old_prs != new_prs) {
+ if (old_prs == PRS_ISOLATED)
+ update_flag(CS_SCHED_LOAD_BALANCE, cs, 1);
+ else if (new_prs == PRS_ISOLATED)
+ update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
+ }
notify_partition_change(cs, old_prs);
-
return 0;
}
@@ -1519,6 +1535,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp,
if ((cp != cs) && old_prs) {
switch (parent->partition_root_state) {
case PRS_ROOT:
+ case PRS_ISOLATED:
update_parent = true;
break;
@@ -1528,7 +1545,8 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp,
* invalid, child partition roots become
* invalid too.
*/
- new_prs = PRS_INVALID_ROOT;
+ if (is_partition_valid(cp))
+ new_prs = -cp->partition_root_state;
break;
}
}
@@ -2110,6 +2128,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
static int update_prstate(struct cpuset *cs, int new_prs)
{
int err = 0, old_prs = cs->partition_root_state;
+ bool sched_domain_rebuilt = false;
struct cpuset *parent = parent_cs(cs);
struct tmpmasks tmpmask;
@@ -2120,8 +2139,10 @@ static int update_prstate(struct cpuset *cs, int new_prs)
* For a previously invalid partition root, leave it at being
* invalid if new_prs is not "member".
*/
- if (new_prs && is_prs_invalid(old_prs))
+ if (new_prs && is_prs_invalid(old_prs)) {
+ cs->partition_root_state = -new_prs;
return 0;
+ }
if (alloc_cpumasks(NULL, &tmpmask))
return -ENOMEM;
@@ -2147,6 +2168,22 @@ static int update_prstate(struct cpuset *cs, int new_prs)
update_flag(CS_CPU_EXCLUSIVE, cs, 0);
goto out;
}
+
+ if (new_prs == PRS_ISOLATED) {
+ /*
+ * Disable the load balance flag should not return an
+ * error unless the system is running out of memory.
+ */
+ update_flag(CS_SCHED_LOAD_BALANCE, cs, 0);
+ sched_domain_rebuilt = true;
+ }
+ } else if (old_prs && new_prs) {
+ /*
+ * A change in load balance state only, no change in cpumasks.
+ */
+ update_flag(CS_SCHED_LOAD_BALANCE, cs, (new_prs != PRS_ISOLATED));
+ sched_domain_rebuilt = true;
+ goto out; /* Sched domain is rebuilt in update_flag() */
} else {
/*
* Switching back to member is always allowed even if it
@@ -2168,6 +2205,12 @@ static int update_prstate(struct cpuset *cs, int new_prs)
/* Turning off CS_CPU_EXCLUSIVE will not return error */
update_flag(CS_CPU_EXCLUSIVE, cs, 0);
+
+ if (!is_sched_load_balance(cs)) {
+ /* Make sure load balance is on */
+ update_flag(CS_SCHED_LOAD_BALANCE, cs, 1);
+ sched_domain_rebuilt = true;
+ }
}
update_tasks_cpumask(parent);
@@ -2175,13 +2218,14 @@ static int update_prstate(struct cpuset *cs, int new_prs)
if (parent->child_ecpus_count)
update_sibling_cpumasks(parent, cs, &tmpmask);
- rebuild_sched_domains_locked();
+ if (!sched_domain_rebuilt)
+ rebuild_sched_domains_locked();
out:
/*
* Make partition invalid if an error happen
*/
if (err)
- new_prs = PRS_INVALID_ROOT;
+ new_prs = -new_prs;
spin_lock_irq(&callback_lock);
cs->partition_root_state = new_prs;
spin_unlock_irq(&callback_lock);
@@ -2691,12 +2735,18 @@ static int sched_partition_show(struct seq_file *seq, void *v)
case PRS_ROOT:
seq_puts(seq, "root\n");
break;
+ case PRS_ISOLATED:
+ seq_puts(seq, "isolated\n");
+ break;
case PRS_MEMBER:
seq_puts(seq, "member\n");
break;
case PRS_INVALID_ROOT:
seq_puts(seq, "root invalid\n");
break;
+ case PRS_INVALID_ISOLATED:
+ seq_puts(seq, "isolated invalid\n");
+ break;
}
return 0;
}
@@ -2717,6 +2767,8 @@ static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf,
val = PRS_ROOT;
else if (!strcmp(buf, "member"))
val = PRS_MEMBER;
+ else if (!strcmp(buf, "isolated"))
+ val = PRS_ISOLATED;
else
return -EINVAL;
From 7476a636d3100120330145d6dc408cd279a31039 Mon Sep 17 00:00:00 2001
From: Waiman Long <longman@redhat.com>
Date: Thu, 1 Sep 2022 16:57:41 -0400
Subject: [PATCH 14/25] cgroup/cpuset: Show invalid partition reason string
There are a number of different reasons which can cause a partition to
become invalid. A user seeing an invalid partition may not know exactly
why. To help user to get a better understanding of the underlying reason,
The cpuset.cpus.partition control file, when read, will now report the
reason why a partition become invalid. When a partition does become
invalid, reading the control file will show "root invalid (<reason>)"
where <reason> is a string that describes why the partition is invalid.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/cpuset.c | 93 ++++++++++++++++++++++++++++++++++--------
1 file changed, 75 insertions(+), 18 deletions(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index f53ca022549c7..15fcd2f861083 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -86,6 +86,30 @@ struct fmeter {
spinlock_t lock; /* guards read or write of above */
};
+/*
+ * Invalid partition error code
+ */
+enum prs_errcode {
+ PERR_NONE = 0,
+ PERR_INVCPUS,
+ PERR_INVPARENT,
+ PERR_NOTPART,
+ PERR_NOTEXCL,
+ PERR_NOCPUS,
+ PERR_HOTPLUG,
+ PERR_CPUSEMPTY,
+};
+
+static const char * const perr_strings[] = {
+ [PERR_INVCPUS] = "Invalid cpu list in cpuset.cpus",
+ [PERR_INVPARENT] = "Parent is an invalid partition root",
+ [PERR_NOTPART] = "Parent is not a partition root",
+ [PERR_NOTEXCL] = "Cpu list in cpuset.cpus not exclusive",
+ [PERR_NOCPUS] = "Parent unable to distribute cpu downstream",
+ [PERR_HOTPLUG] = "No cpu available due to hotplug",
+ [PERR_CPUSEMPTY] = "cpuset.cpus is empty",
+};
+
struct cpuset {
struct cgroup_subsys_state css;
@@ -169,6 +193,9 @@ struct cpuset {
int use_parent_ecpus;
int child_ecpus_count;
+ /* Invalid partition error code, not lock protected */
+ enum prs_errcode prs_err;
+
/* Handle for cpuset.cpus.partition */
struct cgroup_file partition_file;
};
@@ -298,6 +325,10 @@ static inline void notify_partition_change(struct cpuset *cs, int old_prs)
if (old_prs == cs->partition_root_state)
return;
cgroup_file_notify(&cs->partition_file);
+
+ /* Reset prs_err if not invalid */
+ if (is_partition_valid(cs))
+ WRITE_ONCE(cs->prs_err, PERR_NONE);
}
static struct cpuset top_cpuset = {
@@ -1235,7 +1266,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
* @cmd: Partition root state change command
* @newmask: Optional new cpumask for partcmd_update
* @tmp: Temporary addmask and delmask
- * Return: 0 or -1 (error)
+ * Return: 0 or a partition root state error code
*
* For partcmd_enable, the cpuset is being transformed from a non-partition
* root to a partition root. The cpus_allowed mask of the given cpuset will
@@ -1261,7 +1292,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
*
* The partcmd_update command is used by update_cpumasks_hier() with newmask
* NULL and update_cpumask() with newmask set. The callers won't check for
- * error and so partition_root_state will be updated directly.
+ * error and so partition_root_state and prs_error will be updated directly.
*/
static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
struct cpumask *newmask,
@@ -1271,7 +1302,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
int adding; /* Moving cpus from effective_cpus to subparts_cpus */
int deleting; /* Moving cpus from subparts_cpus to effective_cpus */
int old_prs, new_prs;
- bool part_error = false; /* Partition error? */
+ int part_error = PERR_NONE; /* Partition error? */
percpu_rwsem_assert_held(&cpuset_rwsem);
@@ -1280,10 +1311,13 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
* The new cpumask, if present, or the current cpus_allowed must
* not be empty.
*/
- if (!is_partition_valid(parent) ||
- (newmask && cpumask_empty(newmask)) ||
+ if (!is_partition_valid(parent)) {
+ return is_partition_invalid(parent)
+ ? PERR_INVPARENT : PERR_NOTPART;
+ }
+ if ((newmask && cpumask_empty(newmask)) ||
(!newmask && cpumask_empty(cs->cpus_allowed)))
- return -1;
+ return PERR_CPUSEMPTY;
/*
* new_prs will only be changed for the partcmd_update command.
@@ -1296,7 +1330,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
* doesn't overlap parent's cpus_allowed.
*/
if (!cpumask_intersects(cs->cpus_allowed, parent->cpus_allowed))
- return -1;
+ return PERR_INVCPUS;
/*
* A parent can be left with no CPU as long as there is no
@@ -1304,7 +1338,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
*/
if (!cpumask_intersects(cs->cpus_allowed, parent->effective_cpus) &&
partition_is_populated(parent, cs))
- return -1;
+ return PERR_NOCPUS;
cpumask_copy(tmp->addmask, cs->cpus_allowed);
adding = true;
@@ -1341,7 +1375,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
cpumask_subset(parent->effective_cpus, tmp->addmask) &&
!cpumask_intersects(tmp->delmask, cpu_active_mask) &&
partition_is_populated(parent, cs)) {
- part_error = true;
+ part_error = PERR_NOCPUS;
adding = false;
deleting = cpumask_and(tmp->delmask, cs->cpus_allowed,
parent->subparts_cpus);
@@ -1373,7 +1407,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
(adding &&
cpumask_subset(parent->effective_cpus, tmp->addmask) &&
partition_is_populated(parent, cs))) {
- part_error = true;
+ part_error = PERR_NOCPUS;
adding = false;
}
@@ -1382,6 +1416,8 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
deleting = cpumask_and(tmp->delmask, cs->cpus_allowed,
parent->subparts_cpus);
}
+ if (part_error)
+ WRITE_ONCE(cs->prs_err, part_error);
if (cmd == partcmd_update) {
/*
@@ -1412,7 +1448,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
if (old_prs != new_prs) {
if (is_prs_invalid(old_prs) && !is_cpu_exclusive(cs) &&
(update_flag(CS_CPU_EXCLUSIVE, cs, 1) < 0))
- return -1;
+ return PERR_NOTEXCL;
if (is_prs_invalid(new_prs) && is_cpu_exclusive(cs))
update_flag(CS_CPU_EXCLUSIVE, cs, 0);
}
@@ -1547,6 +1583,9 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp,
*/
if (is_partition_valid(cp))
new_prs = -cp->partition_root_state;
+ WRITE_ONCE(cp->prs_err,
+ is_partition_invalid(parent)
+ ? PERR_INVPARENT : PERR_NOTPART);
break;
}
}
@@ -2121,13 +2160,13 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
* update_prstate - update partition_root_state
* @cs: the cpuset to update
* @new_prs: new partition root state
- * Return: 0 if successful, < 0 if error
+ * Return: 0 if successful, != 0 if error
*
* Call with cpuset_rwsem held.
*/
static int update_prstate(struct cpuset *cs, int new_prs)
{
- int err = 0, old_prs = cs->partition_root_state;
+ int err = PERR_NONE, old_prs = cs->partition_root_state;
bool sched_domain_rebuilt = false;
struct cpuset *parent = parent_cs(cs);
struct tmpmasks tmpmask;
@@ -2154,13 +2193,15 @@ static int update_prstate(struct cpuset *cs, int new_prs)
* cannot be empty.
*/
if (cpumask_empty(cs->cpus_allowed)) {
- err = 1;
+ err = PERR_CPUSEMPTY;
goto out;
}
err = update_flag(CS_CPU_EXCLUSIVE, cs, 1);
- if (err)
+ if (err) {
+ err = PERR_NOTEXCL;
goto out;
+ }
err = update_parent_subparts_cpumask(cs, partcmd_enable,
NULL, &tmpmask);
@@ -2730,6 +2771,7 @@ static s64 cpuset_read_s64(struct cgroup_subsys_state *css, struct cftype *cft)
static int sched_partition_show(struct seq_file *seq, void *v)
{
struct cpuset *cs = css_cs(seq_css(seq));
+ const char *err, *type = NULL;
switch (cs->partition_root_state) {
case PRS_ROOT:
@@ -2742,9 +2784,17 @@ static int sched_partition_show(struct seq_file *seq, void *v)
seq_puts(seq, "member\n");
break;
case PRS_INVALID_ROOT:
- seq_puts(seq, "root invalid\n");
- break;
+ type = "root";
+ fallthrough;
case PRS_INVALID_ISOLATED:
+ if (!type)
+ type = "isolated";
+ err = perr_strings[READ_ONCE(cs->prs_err)];
+ if (err)
+ seq_printf(seq, "%s invalid (%s)\n", type, err);
+ else
+ seq_printf(seq, "%s invalid\n", type);
+ break;
seq_puts(seq, "isolated invalid\n");
break;
}
@@ -3335,7 +3385,7 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
*/
if (is_partition_valid(cs) && (!parent->nr_subparts_cpus ||
(cpumask_empty(&new_cpus) && partition_is_populated(cs, NULL)))) {
- int old_prs;
+ int old_prs, parent_prs;
update_parent_subparts_cpumask(cs, partcmd_disable, NULL, tmp);
if (cs->nr_subparts_cpus) {
@@ -3347,10 +3397,17 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp)
}
old_prs = cs->partition_root_state;
+ parent_prs = parent->partition_root_state;
if (is_partition_valid(cs)) {
spin_lock_irq(&callback_lock);
make_partition_invalid(cs);
spin_unlock_irq(&callback_lock);
+ if (is_prs_invalid(parent_prs))
+ WRITE_ONCE(cs->prs_err, PERR_INVPARENT);
+ else if (!parent_prs)
+ WRITE_ONCE(cs->prs_err, PERR_NOTPART);
+ else
+ WRITE_ONCE(cs->prs_err, PERR_HOTPLUG);
notify_partition_change(cs, old_prs);
}
cpuset_force_rebuild();
From 74027a6535fdabef69c57234359d9fbdb4597398 Mon Sep 17 00:00:00 2001
From: Waiman Long <longman@redhat.com>
Date: Thu, 1 Sep 2022 16:57:42 -0400
Subject: [PATCH 15/25] cgroup/cpuset: Relocate a code block in
validate_change()
This patch moves down the exclusive cpu and memory check in
validate_change(). There is no functional change.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/cpuset.c | 32 ++++++++++++++++----------------
1 file changed, 16 insertions(+), 16 deletions(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 15fcd2f861083..b0d921d03f628 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -741,22 +741,6 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial)
par = parent_cs(cur);
- /*
- * If either I or some sibling (!= me) is exclusive, we can't
- * overlap
- */
- ret = -EINVAL;
- cpuset_for_each_child(c, css, par) {
- if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
- c != cur &&
- cpumask_intersects(trial->cpus_allowed, c->cpus_allowed))
- goto out;
- if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
- c != cur &&
- nodes_intersects(trial->mems_allowed, c->mems_allowed))
- goto out;
- }
-
/*
* Cpusets with tasks - existing or newly being attached - can't
* be changed to have empty cpus_allowed or mems_allowed.
@@ -781,6 +765,22 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial)
trial->cpus_allowed))
goto out;
+ /*
+ * If either I or some sibling (!= me) is exclusive, we can't
+ * overlap
+ */
+ ret = -EINVAL;
+ cpuset_for_each_child(c, css, par) {
+ if ((is_cpu_exclusive(trial) || is_cpu_exclusive(c)) &&
+ c != cur &&
+ cpumask_intersects(trial->cpus_allowed, c->cpus_allowed))
+ goto out;
+ if ((is_mem_exclusive(trial) || is_mem_exclusive(c)) &&
+ c != cur &&
+ nodes_intersects(trial->mems_allowed, c->mems_allowed))
+ goto out;
+ }
+
ret = 0;
out:
rcu_read_unlock();
From d7c8142d5a5534c3c7de214e35a40a493a32b98e Mon Sep 17 00:00:00 2001
From: Waiman Long <longman@redhat.com>
Date: Thu, 1 Sep 2022 16:57:43 -0400
Subject: [PATCH 16/25] cgroup/cpuset: Make partition invalid if cpumask change
violates exclusivity rule
Currently, changes in "cpust.cpus" of a partition root is not allowed if
it violates the sibling cpu exclusivity rule when the check is done
in the validate_change() function. That is inconsistent with the
other cpuset changes that are always allowed but may make a partition
invalid.
Update the cpuset code to allow cpumask change even if it violates the
sibling cpu exclusivity rule, but invalidate the partition instead
just like the other changes. However, other sibling partitions with
conflicting cpumask will also be invalidated in order to not violating
the exclusivity rule. This behavior is specific to this partition
rule violation.
Note that a previous commit has made sibling cpu exclusivity rule check
the last check of validate_change(). So if -EINVAL is returned, we can
be sure that sibling cpu exclusivity rule violation is the only rule
that is broken.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/cpuset.c | 69 ++++++++++++++++++++++++++++++++++++------
1 file changed, 60 insertions(+), 9 deletions(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index b0d921d03f628..6baa977a71ba4 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1256,6 +1256,7 @@ enum subparts_cmd {
partcmd_enable, /* Enable partition root */
partcmd_disable, /* Disable partition root */
partcmd_update, /* Update parent's subparts_cpus */
+ partcmd_invalidate, /* Make partition invalid */
};
static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
@@ -1286,13 +1287,17 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
* or vice versa. An error code will only be returned if transitioning from
* invalid to valid violates the exclusivity rule.
*
+ * For partcmd_invalidate, the current partition will be made invalid.
+ *
* The partcmd_enable and partcmd_disable commands are used by
* update_prstate(). An error code may be returned and the caller will check
* for error.
*
* The partcmd_update command is used by update_cpumasks_hier() with newmask
- * NULL and update_cpumask() with newmask set. The callers won't check for
- * error and so partition_root_state and prs_error will be updated directly.
+ * NULL and update_cpumask() with newmask set. The partcmd_invalidate is used
+ * by update_cpumask() with NULL newmask. In both cases, the callers won't
+ * check for error and so partition_root_state and prs_error will be updated
+ * directly.
*/
static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
struct cpumask *newmask,
@@ -1320,7 +1325,8 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
return PERR_CPUSEMPTY;
/*
- * new_prs will only be changed for the partcmd_update command.
+ * new_prs will only be changed for the partcmd_update and
+ * partcmd_invalidate commands.
*/
adding = deleting = false;
old_prs = new_prs = cs->partition_root_state;
@@ -1350,6 +1356,20 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
deleting = !is_prs_invalid(old_prs) &&
cpumask_and(tmp->delmask, cs->cpus_allowed,
parent->subparts_cpus);
+ } else if (cmd == partcmd_invalidate) {
+ if (is_prs_invalid(old_prs))
+ return 0;
+
+ /*
+ * Make the current partition invalid. It is assumed that
+ * invalidation is caused by violating cpu exclusivity rule.
+ */
+ deleting = cpumask_and(tmp->delmask, cs->cpus_allowed,
+ parent->subparts_cpus);
+ if (old_prs > 0) {
+ new_prs = -old_prs;
+ part_error = PERR_NOTEXCL;
+ }
} else if (newmask) {
/*
* partcmd_update with newmask:
@@ -1403,6 +1423,7 @@ static int update_parent_subparts_cpumask(struct cpuset *cs, int cmd,
parent->cpus_allowed);
adding = cpumask_andnot(tmp->addmask, tmp->addmask,
parent->subparts_cpus);
+
if ((is_partition_valid(cs) && !parent->nr_subparts_cpus) ||
(adding &&
cpumask_subset(parent->effective_cpus, tmp->addmask) &&
@@ -1709,6 +1730,7 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
{
int retval;
struct tmpmasks tmp;
+ bool invalidate = false;
/* top_cpuset.cpus_allowed tracks cpu_online_mask; it's read-only */
if (cs == &top_cpuset)
@@ -1736,10 +1758,6 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
if (cpumask_equal(cs->cpus_allowed, trialcs->cpus_allowed))
return 0;
- retval = validate_change(cs, trialcs);
- if (retval < 0)
- return retval;
-
#ifdef CONFIG_CPUMASK_OFFSTACK
/*
* Use the cpumasks in trialcs for tmpmasks when they are pointers
@@ -1750,9 +1768,42 @@ static int update_cpumask(struct cpuset *cs, struct cpuset *trialcs,
tmp.new_cpus = trialcs->cpus_allowed;
#endif
+ retval = validate_change(cs, trialcs);
+
+ if ((retval == -EINVAL) && cgroup_subsys_on_dfl(cpuset_cgrp_subsys)) {
+ struct cpuset *cp, *parent;
+ struct cgroup_subsys_state *css;
+
+ /*
+ * The -EINVAL error code indicates that partition sibling
+ * CPU exclusivity rule has been violated. We still allow
+ * the cpumask change to proceed while invalidating the
+ * partition. However, any conflicting sibling partitions
+ * have to be marked as invalid too.
+ */
+ invalidate = true;
+ rcu_read_lock();
+ parent = parent_cs(cs);
+ cpuset_for_each_child(cp, css, parent)
+ if (is_partition_valid(cp) &&
+ cpumask_intersects(trialcs->cpus_allowed, cp->cpus_allowed)) {
+ rcu_read_unlock();
+ update_parent_subparts_cpumask(cp, partcmd_invalidate, NULL, &tmp);
+ rcu_read_lock();
+ }
+ rcu_read_unlock();
+ retval = 0;
+ }
+ if (retval < 0)
+ return retval;
+
if (cs->partition_root_state) {
- update_parent_subparts_cpumask(cs, partcmd_update,
- trialcs->cpus_allowed, &tmp);
+ if (invalidate)
+ update_parent_subparts_cpumask(cs, partcmd_invalidate,
+ NULL, &tmp);
+ else
+ update_parent_subparts_cpumask(cs, partcmd_update,
+ trialcs->cpus_allowed, &tmp);
}
compute_effective_cpumask(trialcs->effective_cpus, trialcs,
From 8cbfdc24fc55a6f9fb1a1f9ed0d33614d7ae7ce0 Mon Sep 17 00:00:00 2001
From: Waiman Long <longman@redhat.com>
Date: Thu, 1 Sep 2022 16:57:44 -0400
Subject: [PATCH 17/25] cgroup/cpuset: Update description of
cpuset.cpus.partition in cgroup-v2.rst
Update Documentation/admin-guide/cgroup-v2.rst on the newly introduced
"isolated" cpuset partition type as well as other changes made in other
cpuset patches.
Signed-off-by: Waiman Long <longman@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
Documentation/admin-guide/cgroup-v2.rst | 156 +++++++++++++-----------
1 file changed, 87 insertions(+), 69 deletions(-)
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index be4a77baf7841..9319c29f7eac3 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -2185,75 +2185,93 @@ Cpuset Interface Files
It accepts only the following input values when written to.
- ======== ================================
- "root" a partition root
- "member" a non-root member of a partition
- ======== ================================
-
- When set to be a partition root, the current cgroup is the
- root of a new partition or scheduling domain that comprises
- itself and all its descendants except those that are separate
- partition roots themselves and their descendants. The root
- cgroup is always a partition root.
-
- There are constraints on where a partition root can be set.
- It can only be set in a cgroup if all the following conditions
- are true.
-
- 1) The "cpuset.cpus" is not empty and the list of CPUs are
- exclusive, i.e. they are not shared by any of its siblings.
- 2) The parent cgroup is a partition root.
- 3) The "cpuset.cpus" is also a proper subset of the parent's
- "cpuset.cpus.effective".
- 4) There is no child cgroups with cpuset enabled. This is for
- eliminating corner cases that have to be handled if such a
- condition is allowed.
-
- Setting it to partition root will take the CPUs away from the
- effective CPUs of the parent cgroup. Once it is set, this
- file cannot be reverted back to "member" if there are any child
- cgroups with cpuset enabled.
-
- A parent partition cannot distribute all its CPUs to its
- child partitions. There must be at least one cpu left in the
- parent partition.
-
- Once becoming a partition root, changes to "cpuset.cpus" is
- generally allowed as long as the first condition above is true,
- the change will not take away all the CPUs from the parent
- partition and the new "cpuset.cpus" value is a superset of its
- children's "cpuset.cpus" values.
-
- Sometimes, external factors like changes to ancestors'
- "cpuset.cpus" or cpu hotplug can cause the state of the partition
- root to change. On read, the "cpuset.sched.partition" file
- can show the following values.
-
- ============== ==============================
- "member" Non-root member of a partition
- "root" Partition root
- "root invalid" Invalid partition root
- ============== ==============================
-
- It is a partition root if the first 2 partition root conditions
- above are true and at least one CPU from "cpuset.cpus" is
- granted by the parent cgroup.
-
- A partition root can become invalid if none of CPUs requested
- in "cpuset.cpus" can be granted by the parent cgroup or the
- parent cgroup is no longer a partition root itself. In this
- case, it is not a real partition even though the restriction
- of the first partition root condition above will still apply.
- The cpu affinity of all the tasks in the cgroup will then be
- associated with CPUs in the nearest ancestor partition.
-
- An invalid partition root can be transitioned back to a
- real partition root if at least one of the requested CPUs
- can now be granted by its parent. In this case, the cpu
- affinity of all the tasks in the formerly invalid partition
- will be associated to the CPUs of the newly formed partition.
- Changing the partition state of an invalid partition root to
- "member" is always allowed even if child cpusets are present.
+ ========== =====================================
+ "member" Non-root member of a partition
+ "root" Partition root
+ "isolated" Partition root without load balancing
+ ========== =====================================
+
+ The root cgroup is always a partition root and its state
+ cannot be changed. All other non-root cgroups start out as
+ "member".
+
+ When set to "root", the current cgroup is the root of a new
+ partition or scheduling domain that comprises itself and all
+ its descendants except those that are separate partition roots
+ themselves and their descendants.
+
+ When set to "isolated", the CPUs in that partition root will
+ be in an isolated state without any load balancing from the
+ scheduler. Tasks placed in such a partition with multiple
+ CPUs should be carefully distributed and bound to each of the
+ individual CPUs for optimal performance.
+
+ The value shown in "cpuset.cpus.effective" of a partition root
+ is the CPUs that the partition root can dedicate to a potential
+ new child partition root. The new child subtracts available
+ CPUs from its parent "cpuset.cpus.effective".
+
+ A partition root ("root" or "isolated") can be in one of the
+ two possible states - valid or invalid. An invalid partition
+ root is in a degraded state where some state information may
+ be retained, but behaves more like a "member".
+
+ All possible state transitions among "member", "root" and
+ "isolated" are allowed.
+
+ On read, the "cpuset.cpus.partition" file can show the following
+ values.
+
+ ============================= =====================================
+ "member" Non-root member of a partition
+ "root" Partition root
+ "isolated" Partition root without load balancing
+ "root invalid (<reason>)" Invalid partition root
+ "isolated invalid (<reason>)" Invalid isolated partition root
+ ============================= =====================================
+
+ In the case of an invalid partition root, a descriptive string on
+ why the partition is invalid is included within parentheses.
+
+ For a partition root to become valid, the following conditions
+ must be met.
+
+ 1) The "cpuset.cpus" is exclusive with its siblings , i.e. they
+ are not shared by any of its siblings (exclusivity rule).
+ 2) The parent cgroup is a valid partition root.
+ 3) The "cpuset.cpus" is not empty and must contain at least
+ one of the CPUs from parent's "cpuset.cpus", i.e. they overlap.
+ 4) The "cpuset.cpus.effective" cannot be empty unless there is
+ no task associated with this partition.
+
+ External events like hotplug or changes to "cpuset.cpus" can
+ cause a valid partition root to become invalid and vice versa.
+ Note that a task cannot be moved to a cgroup with empty
+ "cpuset.cpus.effective".
+
+ For a valid partition root with the sibling cpu exclusivity
+ rule enabled, changes made to "cpuset.cpus" that violate the
+ exclusivity rule will invalidate the partition as well as its
+ sibiling partitions with conflicting cpuset.cpus values. So
+ care must be taking in changing "cpuset.cpus".
+
+ A valid non-root parent partition may distribute out all its CPUs
+ to its child partitions when there is no task associated with it.
+
+ Care must be taken to change a valid partition root to
+ "member" as all its child partitions, if present, will become
+ invalid causing disruption to tasks running in those child
+ partitions. These inactivated partitions could be recovered if
+ their parent is switched back to a partition root with a proper
+ set of "cpuset.cpus".
+
+ Poll and inotify events are triggered whenever the state of
+ "cpuset.cpus.partition" changes. That includes changes caused
+ by write to "cpuset.cpus.partition", cpu hotplug or other
+ changes that modify the validity status of the partition.
+ This will allow user space agents to monitor unexpected changes
+ to "cpuset.cpus.partition" without the need to do continuous
+ polling.
Device controller
From a8c52eba880a6e8c07fc2130604f8e386b90b763 Mon Sep 17 00:00:00 2001
From: Waiman Long <longman@redhat.com>
Date: Thu, 1 Sep 2022 16:57:45 -0400
Subject: [PATCH 18/25] kselftest/cgroup: Add cpuset v2 partition root state
test
Add a test script test_cpuset_prs.sh with a helper program wait_inotify
for exercising the cpuset v2 partition root state code.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
tools/testing/selftests/cgroup/.gitignore | 1 +
tools/testing/selftests/cgroup/Makefile | 5 +-
.../selftests/cgroup/test_cpuset_prs.sh | 674 ++++++++++++++++++
tools/testing/selftests/cgroup/wait_inotify.c | 87 +++
4 files changed, 765 insertions(+), 2 deletions(-)
create mode 100755 tools/testing/selftests/cgroup/test_cpuset_prs.sh
create mode 100644 tools/testing/selftests/cgroup/wait_inotify.c
diff --git a/tools/testing/selftests/cgroup/.gitignore b/tools/testing/selftests/cgroup/.gitignore
index 306ee1b01e72f..c4a57e69f749e 100644
--- a/tools/testing/selftests/cgroup/.gitignore
+++ b/tools/testing/selftests/cgroup/.gitignore
@@ -5,3 +5,4 @@ test_freezer
test_kmem
test_kill
test_cpu
+wait_inotify
diff --git a/tools/testing/selftests/cgroup/Makefile b/tools/testing/selftests/cgroup/Makefile
index 478217cc13714..3d263747d2ad0 100644
--- a/tools/testing/selftests/cgroup/Makefile
+++ b/tools/testing/selftests/cgroup/Makefile
@@ -1,10 +1,11 @@
# SPDX-License-Identifier: GPL-2.0
CFLAGS += -Wall -pthread
-all:
+all: ${HELPER_PROGS}
TEST_FILES := with_stress.sh
-TEST_PROGS := test_stress.sh
+TEST_PROGS := test_stress.sh test_cpuset_prs.sh
+TEST_GEN_FILES := wait_inotify
TEST_GEN_PROGS = test_memcontrol
TEST_GEN_PROGS += test_kmem
TEST_GEN_PROGS += test_core
diff --git a/tools/testing/selftests/cgroup/test_cpuset_prs.sh b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
new file mode 100755
index 0000000000000..526d2c42d8706
--- /dev/null
+++ b/tools/testing/selftests/cgroup/test_cpuset_prs.sh
@@ -0,0 +1,674 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Test for cpuset v2 partition root state (PRS)
+#
+# The sched verbose flag is set, if available, so that the console log
+# can be examined for the correct setting of scheduling domain.
+#
+
+skip_test() {
+ echo "$1"
+ echo "Test SKIPPED"
+ exit 0
+}
+
+[[ $(id -u) -eq 0 ]] || skip_test "Test must be run as root!"
+
+# Set sched verbose flag, if available
+[[ -d /sys/kernel/debug/sched ]] && echo Y > /sys/kernel/debug/sched/verbose
+
+# Get wait_inotify location
+WAIT_INOTIFY=$(cd $(dirname $0); pwd)/wait_inotify
+
+# Find cgroup v2 mount point
+CGROUP2=$(mount -t cgroup2 | head -1 | awk -e '{print $3}')
+[[ -n "$CGROUP2" ]] || skip_test "Cgroup v2 mount point not found!"
+
+CPUS=$(lscpu | grep "^CPU(s)" | sed -e "s/.*:[[:space:]]*//")
+[[ $CPUS -lt 8 ]] && skip_test "Test needs at least 8 cpus available!"
+
+# Set verbose flag and delay factor
+PROG=$1
+VERBOSE=
+DELAY_FACTOR=1
+while [[ "$1" = -* ]]
+do
+ case "$1" in
+ -v) VERBOSE=1
+ break
+ ;;
+ -d) DELAY_FACTOR=$2
+ shift
+ break
+ ;;
+ *) echo "Usage: $PROG [-v] [-d <delay-factor>"
+ exit
+ ;;
+ esac
+ shift
+done
+
+cd $CGROUP2
+echo +cpuset > cgroup.subtree_control
+[[ -d test ]] || mkdir test
+cd test
+
+# Pause in ms
+pause()
+{
+ DELAY=$1
+ LOOP=0
+ while [[ $LOOP -lt $DELAY_FACTOR ]]
+ do
+ sleep $DELAY
+ ((LOOP++))
+ done
+ return 0
+}
+
+console_msg()
+{
+ MSG=$1
+ echo "$MSG"
+ echo "" > /dev/console
+ echo "$MSG" > /dev/console
+ pause 0.01
+}
+
+test_partition()
+{
+ EXPECTED_VAL=$1
+ echo $EXPECTED_VAL > cpuset.cpus.partition
+ [[ $? -eq 0 ]] || exit 1
+ ACTUAL_VAL=$(cat cpuset.cpus.partition)
+ [[ $ACTUAL_VAL != $EXPECTED_VAL ]] && {
+ echo "cpuset.cpus.partition: expect $EXPECTED_VAL, found $EXPECTED_VAL"
+ echo "Test FAILED"
+ exit 1
+ }
+}
+
+test_effective_cpus()
+{
+ EXPECTED_VAL=$1
+ ACTUAL_VAL=$(cat cpuset.cpus.effective)
+ [[ "$ACTUAL_VAL" != "$EXPECTED_VAL" ]] && {
+ echo "cpuset.cpus.effective: expect '$EXPECTED_VAL', found '$EXPECTED_VAL'"
+ echo "Test FAILED"
+ exit 1
+ }
+}
+
+# Adding current process to cgroup.procs as a test
+test_add_proc()
+{
+ OUTSTR="$1"
+ ERRMSG=$((echo $$ > cgroup.procs) |& cat)
+ echo $ERRMSG | grep -q "$OUTSTR"
+ [[ $? -ne 0 ]] && {
+ echo "cgroup.procs: expect '$OUTSTR', got '$ERRMSG'"
+ echo "Test FAILED"
+ exit 1
+ }
+ echo $$ > $CGROUP2/cgroup.procs # Move out the task
+}
+
+#
+# Testing the new "isolated" partition root type
+#
+test_isolated()
+{
+ echo 2-3 > cpuset.cpus
+ TYPE=$(cat cpuset.cpus.partition)
+ [[ $TYPE = member ]] || echo member > cpuset.cpus.partition
+
+ console_msg "Change from member to root"
+ test_partition root
+
+ console_msg "Change from root to isolated"
+ test_partition isolated
+
+ console_msg "Change from isolated to member"
+ test_partition member
+
+ console_msg "Change from member to isolated"
+ test_partition isolated
+
+ console_msg "Change from isolated to root"
+ test_partition root
+
+ console_msg "Change from root to member"
+ test_partition member
+
+ #
+ # Testing partition root with no cpu
+ #
+ console_msg "Distribute all cpus to child partition"
+ echo +cpuset > cgroup.subtree_control
+ test_partition root
+
+ mkdir A1
+ cd A1
+ echo 2-3 > cpuset.cpus
+ test_partition root
+ test_effective_cpus 2-3
+ cd ..
+ test_effective_cpus ""
+
+ console_msg "Moving task to partition test"
+ test_add_proc "No space left"
+ cd A1
+ test_add_proc ""
+ cd ..
+
+ console_msg "Shrink and expand child partition"
+ cd A1
+ echo 2 > cpuset.cpus
+ cd ..
+ test_effective_cpus 3
+ cd A1
+ echo 2-3 > cpuset.cpus
+ cd ..
+ test_effective_cpus ""
+
+ # Cleaning up
+ console_msg "Cleaning up"
+ echo $$ > $CGROUP2/cgroup.procs
+ [[ -d A1 ]] && rmdir A1
+}
+
+#
+# Cpuset controller state transition test matrix.
+#
+# Cgroup test hierarchy
+#
+# test -- A1 -- A2 -- A3
+# \- B1
+#
+# P<v> = set cpus.partition (0:member, 1:root, 2:isolated, -1:root invalid)
+# C<l> = add cpu-list
+# S<p> = use prefix in subtree_control
+# T = put a task into cgroup
+# O<c>-<v> = Write <v> to CPU online file of <c>
+#
+SETUP_A123_PARTITIONS="C1-3:P1:S+ C2-3:P1:S+ C3:P1"
+TEST_MATRIX=(
+ # test old-A1 old-A2 old-A3 old-B1 new-A1 new-A2 new-A3 new-B1 fail ECPUs Pstate
+ # ---- ------ ------ ------ ------ ------ ------ ------ ------ ---- ----- ------
+ " S+ C0-1 . . C2-3 S+ C4-5 . . 0 A2:0-1"
+ " S+ C0-1 . . C2-3 P1 . . . 0 "
+ " S+ C0-1 . . C2-3 P1:S+ C0-1:P1 . . 0 "
+ " S+ C0-1 . . C2-3 P1:S+ C1:P1 . . 0 "
+ " S+ C0-1:S+ . . C2-3 . . . P1 0 "
+ " S+ C0-1:P1 . . C2-3 S+ C1 . . 0 "
+ " S+ C0-1:P1 . . C2-3 S+ C1:P1 . . 0 "
+ " S+ C0-1:P1 . . C2-3 S+ C1:P1 . P1 0 "
+ " S+ C0-1:P1 . . C2-3 C4-5 . . . 0 A1:4-5"
+ " S+ C0-1:P1 . . C2-3 S+:C4-5 . . . 0 A1:4-5"
+ " S+ C0-1 . . C2-3:P1 . . . C2 0 "
+ " S+ C0-1 . . C2-3:P1 . . . C4-5 0 B1:4-5"
+ " S+ C0-3:P1:S+ C2-3:P1 . . . . . . 0 A1:0-1,A2:2-3"
+ " S+ C0-3:P1:S+ C2-3:P1 . . C1-3 . . . 0 A1:1,A2:2-3"
+ " S+ C2-3:P1:S+ C3:P1 . . C3 . . . 0 A1:,A2:3 A1:P1,A2:P1"
+ " S+ C2-3:P1:S+ C3:P1 . . C3 P0 . . 0 A1:3,A2:3 A1:P1,A2:P0"
+ " S+ C2-3:P1:S+ C2:P1 . . C2-4 . . . 0 A1:3-4,A2:2"
+ " S+ C2-3:P1:S+ C3:P1 . . C3 . . C0-2 0 A1:,B1:0-2 A1:P1,A2:P1"
+ " S+ $SETUP_A123_PARTITIONS . C2-3 . . . 0 A1:,A2:2,A3:3 A1:P1,A2:P1,A3:P1"
+
+ # CPU offlining cases:
+ " S+ C0-1 . . C2-3 S+ C4-5 . O2-0 0 A1:0-1,B1:3"
+ " S+ C0-3:P1:S+ C2-3:P1 . . O2-0 . . . 0 A1:0-1,A2:3"
+ " S+ C0-3:P1:S+ C2-3:P1 . . O2-0 O2-1 . . 0 A1:0-1,A2:2-3"
+ " S+ C0-3:P1:S+ C2-3:P1 . . O1-0 . . . 0 A1:0,A2:2-3"
+ " S+ C0-3:P1:S+ C2-3:P1 . . O1-0 O1-1 . . 0 A1:0-1,A2:2-3"
+ " S+ C2-3:P1:S+ C3:P1 . . O3-0 O3-1 . . 0 A1:2,A2:3 A1:P1,A2:P1"
+ " S+ C2-3:P1:S+ C3:P2 . . O3-0 O3-1 . . 0 A1:2,A2:3 A1:P1,A2:P2"
+ " S+ C2-3:P1:S+ C3:P1 . . O2-0 O2-1 . . 0 A1:2,A2:3 A1:P1,A2:P1"
+ " S+ C2-3:P1:S+ C3:P2 . . O2-0 O2-1 . . 0 A1:2,A2:3 A1:P1,A2:P2"
+ " S+ C2-3:P1:S+ C3:P1 . . O2-0 . . . 0 A1:,A2:3 A1:P1,A2:P1"
+ " S+ C2-3:P1:S+ C3:P1 . . O3-0 . . . 0 A1:2,A2: A1:P1,A2:P1"
+ " S+ C2-3:P1:S+ C3:P1 . . T:O2-0 . . . 0 A1:3,A2:3 A1:P1,A2:P-1"
+ " S+ C2-3:P1:S+ C3:P1 . . . T:O3-0 . . 0 A1:2,A2:2 A1:P1,A2:P-1"
+ " S+ $SETUP_A123_PARTITIONS . O1-0 . . . 0 A1:,A2:2,A3:3 A1:P1,A2:P1,A3:P1"
+ " S+ $SETUP_A123_PARTITIONS . O2-0 . . . 0 A1:1,A2:,A3:3 A1:P1,A2:P1,A3:P1"
+ " S+ $SETUP_A123_PARTITIONS . O3-0 . . . 0 A1:1,A2:2,A3: A1:P1,A2:P1,A3:P1"
+ " S+ $SETUP_A123_PARTITIONS . T:O1-0 . . . 0 A1:2-3,A2:2-3,A3:3 A1:P1,A2:P-1,A3:P-1"
+ " S+ $SETUP_A123_PARTITIONS . . T:O2-0 . . 0 A1:1,A2:3,A3:3 A1:P1,A2:P1,A3:P-1"
+ " S+ $SETUP_A123_PARTITIONS . . . T:O3-0 . 0 A1:1,A2:2,A3:2 A1:P1,A2:P1,A3:P-1"
+ " S+ $SETUP_A123_PARTITIONS . T:O1-0 O1-1 . . 0 A1:1,A2:2,A3:3 A1:P1,A2:P1,A3:P1"
+ " S+ $SETUP_A123_PARTITIONS . . T:O2-0 O2-1 . 0 A1:1,A2:2,A3:3 A1:P1,A2:P1,A3:P1"
+ " S+ $SETUP_A123_PARTITIONS . . . T:O3-0 O3-1 0 A1:1,A2:2,A3:3 A1:P1,A2:P1,A3:P1"
+ " S+ $SETUP_A123_PARTITIONS . T:O1-0 O2-0 O1-1 . 0 A1:1,A2:,A3:3 A1:P1,A2:P1,A3:P1"
+ " S+ $SETUP_A123_PARTITIONS . T:O1-0 O2-0 O2-1 . 0 A1:2-3,A2:2-3,A3:3 A1:P1,A2:P-1,A3:P-1"
+
+ # test old-A1 old-A2 old-A3 old-B1 new-A1 new-A2 new-A3 new-B1 fail ECPUs Pstate
+ # ---- ------ ------ ------ ------ ------ ------ ------ ------ ---- ----- ------
+ #
+ # Incorrect change to cpuset.cpus invalidates partition root
+ #
+ # Adding CPUs to partition root that are not in parent's
+ # cpuset.cpus is allowed, but those extra CPUs are ignored.
+ " S+ C2-3:P1:S+ C3:P1 . . . C2-4 . . 0 A1:,A2:2-3 A1:P1,A2:P1"
+
+ # Taking away all CPUs from parent or itself if there are tasks
+ # will make the partition invalid.
+ " S+ C2-3:P1:S+ C3:P1 . . T C2-3 . . 0 A1:2-3,A2:2-3 A1:P1,A2:P-1"
+ " S+ $SETUP_A123_PARTITIONS . T:C2-3 . . . 0 A1:2-3,A2:2-3,A3:3 A1:P1,A2:P-1,A3:P-1"
+ " S+ $SETUP_A123_PARTITIONS . T:C2-3:C1-3 . . . 0 A1:1,A2:2,A3:3 A1:P1,A2:P1,A3:P1"
+
+ # Changing a partition root to member makes child partitions invalid
+ " S+ C2-3:P1:S+ C3:P1 . . P0 . . . 0 A1:2-3,A2:3 A1:P0,A2:P-1"
+ " S+ $SETUP_A123_PARTITIONS . C2-3 P0 . . 0 A1:2-3,A2:2-3,A3:3 A1:P1,A2:P0,A3:P-1"
+
+ # cpuset.cpus can contains cpus not in parent's cpuset.cpus as long
+ # as they overlap.
+ " S+ C2-3:P1:S+ . . . . C3-4:P1 . . 0 A1:2,A2:3 A1:P1,A2:P1"
+
+ # Deletion of CPUs distributed to child cgroup is allowed.
+ " S+ C0-1:P1:S+ C1 . C2-3 C4-5 . . . 0 A1:4-5,A2:4-5"
+
+ # To become a valid partition root, cpuset.cpus must overlap parent's
+ # cpuset.cpus.
+ " S+ C0-1:P1 . . C2-3 S+ C4-5:P1 . . 0 A1:0-1,A2:0-1 A1:P1,A2:P-1"
+
+ # Enabling partition with child cpusets is allowed
+ " S+ C0-1:S+ C1 . C2-3 P1 . . . 0 A1:0-1,A2:1 A1:P1"
+
+ # A partition root with non-partition root parent is invalid, but it
+ # can be made valid if its parent becomes a partition root too.
+ " S+ C0-1:S+ C1 . C2-3 . P2 . . 0 A1:0-1,A2:1 A1:P0,A2:P-2"
+ " S+ C0-1:S+ C1:P2 . C2-3 P1 . . . 0 A1:0,A2:1 A1:P1,A2:P2"
+
+ # A non-exclusive cpuset.cpus change will invalidate partition and its siblings
+ " S+ C0-1:P1 . . C2-3 C0-2 . . . 0 A1:0-2,B1:2-3 A1:P-1,B1:P0"
+ " S+ C0-1:P1 . . P1:C2-3 C0-2 . . . 0 A1:0-2,B1:2-3 A1:P-1,B1:P-1"
+ " S+ C0-1 . . P1:C2-3 C0-2 . . . 0 A1:0-2,B1:2-3 A1:P0,B1:P-1"
+
+ # test old-A1 old-A2 old-A3 old-B1 new-A1 new-A2 new-A3 new-B1 fail ECPUs Pstate
+ # ---- ------ ------ ------ ------ ------ ------ ------ ------ ---- ----- ------
+ # Failure cases:
+
+ # A task cannot be added to a partition with no cpu
+ " S+ C2-3:P1:S+ C3:P1 . . O2-0:T . . . 1 A1:,A2:3 A1:P1,A2:P1"
+)
+
+#
+# Write to the cpu online file
+# $1 - <c>-<v> where <c> = cpu number, <v> value to be written
+#
+write_cpu_online()
+{
+ CPU=${1%-*}
+ VAL=${1#*-}
+ CPUFILE=//sys/devices/system/cpu/cpu${CPU}/online
+ if [[ $VAL -eq 0 ]]
+ then
+ OFFLINE_CPUS="$OFFLINE_CPUS $CPU"
+ else
+ [[ -n "$OFFLINE_CPUS" ]] && {
+ OFFLINE_CPUS=$(echo $CPU $CPU $OFFLINE_CPUS | fmt -1 |\
+ sort | uniq -u)
+ }
+ fi
+ echo $VAL > $CPUFILE
+ pause 0.01
+}
+
+#
+# Set controller state
+# $1 - cgroup directory
+# $2 - state
+# $3 - showerr
+#
+# The presence of ":" in state means transition from one to the next.
+#
+set_ctrl_state()
+{
+ TMPMSG=/tmp/.msg_$$
+ CGRP=$1
+ STATE=$2
+ SHOWERR=${3}${VERBOSE}
+ CTRL=${CTRL:=$CONTROLLER}
+ HASERR=0
+ REDIRECT="2> $TMPMSG"
+ [[ -z "$STATE" || "$STATE" = '.' ]] && return 0
+
+ rm -f $TMPMSG
+ for CMD in $(echo $STATE | sed -e "s/:/ /g")
+ do
+ TFILE=$CGRP/cgroup.procs
+ SFILE=$CGRP/cgroup.subtree_control
+ PFILE=$CGRP/cpuset.cpus.partition
+ CFILE=$CGRP/cpuset.cpus
+ S=$(expr substr $CMD 1 1)
+ if [[ $S = S ]]
+ then
+ PREFIX=${CMD#?}
+ COMM="echo ${PREFIX}${CTRL} > $SFILE"
+ eval $COMM $REDIRECT
+ elif [[ $S = C ]]
+ then
+ CPUS=${CMD#?}
+ COMM="echo $CPUS > $CFILE"
+ eval $COMM $REDIRECT
+ elif [[ $S = P ]]
+ then
+ VAL=${CMD#?}
+ case $VAL in
+ 0) VAL=member
+ ;;
+ 1) VAL=root
+ ;;
+ 2) VAL=isolated
+ ;;
+ *)
+ echo "Invalid partition state - $VAL"
+ exit 1
+ ;;
+ esac
+ COMM="echo $VAL > $PFILE"
+ eval $COMM $REDIRECT
+ elif [[ $S = O ]]
+ then
+ VAL=${CMD#?}
+ write_cpu_online $VAL
+ elif [[ $S = T ]]
+ then
+ COMM="echo 0 > $TFILE"
+ eval $COMM $REDIRECT
+ fi
+ RET=$?
+ [[ $RET -ne 0 ]] && {
+ [[ -n "$SHOWERR" ]] && {
+ echo "$COMM"
+ cat $TMPMSG
+ }
+ HASERR=1
+ }
+ pause 0.01
+ rm -f $TMPMSG
+ done
+ return $HASERR
+}
+
+set_ctrl_state_noerr()
+{
+ CGRP=$1
+ STATE=$2
+ [[ -d $CGRP ]] || mkdir $CGRP
+ set_ctrl_state $CGRP $STATE 1
+ [[ $? -ne 0 ]] && {
+ echo "ERROR: Failed to set $2 to cgroup $1!"
+ exit 1
+ }
+}
+
+online_cpus()
+{
+ [[ -n "OFFLINE_CPUS" ]] && {
+ for C in $OFFLINE_CPUS
+ do
+ write_cpu_online ${C}-1
+ done
+ }
+}
+
+#
+# Return 1 if the list of effective cpus isn't the same as the initial list.
+#
+reset_cgroup_states()
+{
+ echo 0 > $CGROUP2/cgroup.procs
+ online_cpus
+ rmdir A1/A2/A3 A1/A2 A1 B1 > /dev/null 2>&1
+ set_ctrl_state . S-
+ pause 0.01
+}
+
+dump_states()
+{
+ for DIR in A1 A1/A2 A1/A2/A3 B1
+ do
+ ECPUS=$DIR/cpuset.cpus.effective
+ PRS=$DIR/cpuset.cpus.partition
+ [[ -e $ECPUS ]] && echo "$ECPUS: $(cat $ECPUS)"
+ [[ -e $PRS ]] && echo "$PRS: $(cat $PRS)"
+ done
+}
+
+#
+# Check effective cpus
+# $1 - check string, format: <cgroup>:<cpu-list>[,<cgroup>:<cpu-list>]*
+#
+check_effective_cpus()
+{
+ CHK_STR=$1
+ for CHK in $(echo $CHK_STR | sed -e "s/,/ /g")
+ do
+ set -- $(echo $CHK | sed -e "s/:/ /g")
+ CGRP=$1
+ CPUS=$2
+ [[ $CGRP = A2 ]] && CGRP=A1/A2
+ [[ $CGRP = A3 ]] && CGRP=A1/A2/A3
+ FILE=$CGRP/cpuset.cpus.effective
+ [[ -e $FILE ]] || return 1
+ [[ $CPUS = $(cat $FILE) ]] || return 1
+ done
+}
+
+#
+# Check cgroup states
+# $1 - check string, format: <cgroup>:<state>[,<cgroup>:<state>]*
+#
+check_cgroup_states()
+{
+ CHK_STR=$1
+ for CHK in $(echo $CHK_STR | sed -e "s/,/ /g")
+ do
+ set -- $(echo $CHK | sed -e "s/:/ /g")
+ CGRP=$1
+ STATE=$2
+ FILE=
+ EVAL=$(expr substr $STATE 2 2)
+ [[ $CGRP = A2 ]] && CGRP=A1/A2
+ [[ $CGRP = A3 ]] && CGRP=A1/A2/A3
+
+ case $STATE in
+ P*) FILE=$CGRP/cpuset.cpus.partition
+ ;;
+ *) echo "Unknown state: $STATE!"
+ exit 1
+ ;;
+ esac
+ VAL=$(cat $FILE)
+
+ case "$VAL" in
+ member) VAL=0
+ ;;
+ root) VAL=1
+ ;;
+ isolated)
+ VAL=2
+ ;;
+ "root invalid"*)
+ VAL=-1
+ ;;
+ "isolated invalid"*)
+ VAL=-2
+ ;;
+ esac
+ [[ $EVAL != $VAL ]] && return 1
+ done
+ return 0
+}
+
+#
+# Run cpuset state transition test
+# $1 - test matrix name
+#
+# This test is somewhat fragile as delays (sleep x) are added in various
+# places to make sure state changes are fully propagated before the next
+# action. These delays may need to be adjusted if running in a slower machine.
+#
+run_state_test()
+{
+ TEST=$1
+ CONTROLLER=cpuset
+ CPULIST=0-6
+ I=0
+ eval CNT="\${#$TEST[@]}"
+
+ reset_cgroup_states
+ echo $CPULIST > cpuset.cpus
+ echo root > cpuset.cpus.partition
+ console_msg "Running state transition test ..."
+
+ while [[ $I -lt $CNT ]]
+ do
+ echo "Running test $I ..." > /dev/console
+ eval set -- "\${$TEST[$I]}"
+ ROOT=$1
+ OLD_A1=$2
+ OLD_A2=$3
+ OLD_A3=$4
+ OLD_B1=$5
+ NEW_A1=$6
+ NEW_A2=$7
+ NEW_A3=$8
+ NEW_B1=$9
+ RESULT=${10}
+ ECPUS=${11}
+ STATES=${12}
+
+ set_ctrl_state_noerr . $ROOT
+ set_ctrl_state_noerr A1 $OLD_A1
+ set_ctrl_state_noerr A1/A2 $OLD_A2
+ set_ctrl_state_noerr A1/A2/A3 $OLD_A3
+ set_ctrl_state_noerr B1 $OLD_B1
+ RETVAL=0
+ set_ctrl_state A1 $NEW_A1; ((RETVAL += $?))
+ set_ctrl_state A1/A2 $NEW_A2; ((RETVAL += $?))
+ set_ctrl_state A1/A2/A3 $NEW_A3; ((RETVAL += $?))
+ set_ctrl_state B1 $NEW_B1; ((RETVAL += $?))
+
+ [[ $RETVAL -ne $RESULT ]] && {
+ echo "Test $TEST[$I] failed result check!"
+ eval echo \"\${$TEST[$I]}\"
+ dump_states
+ online_cpus
+ exit 1
+ }
+
+ [[ -n "$ECPUS" && "$ECPUS" != . ]] && {
+ check_effective_cpus $ECPUS
+ [[ $? -ne 0 ]] && {
+ echo "Test $TEST[$I] failed effective CPU check!"
+ eval echo \"\${$TEST[$I]}\"
+ echo
+ dump_states
+ online_cpus
+ exit 1
+ }
+ }
+
+ [[ -n "$STATES" ]] && {
+ check_cgroup_states $STATES
+ [[ $? -ne 0 ]] && {
+ echo "FAILED: Test $TEST[$I] failed states check!"
+ eval echo \"\${$TEST[$I]}\"
+ echo
+ dump_states
+ online_cpus
+ exit 1
+ }
+ }
+
+ reset_cgroup_states
+ #
+ # Check to see if effective cpu list changes
+ #
+ pause 0.05
+ NEWLIST=$(cat cpuset.cpus.effective)
+ [[ $NEWLIST != $CPULIST ]] && {
+ echo "Effective cpus changed to $NEWLIST after test $I!"
+ exit 1
+ }
+ [[ -n "$VERBOSE" ]] && echo "Test $I done."
+ ((I++))
+ done
+ echo "All $I tests of $TEST PASSED."
+
+ echo member > cpuset.cpus.partition
+}
+
+#
+# Wait for inotify event for the given file and read it
+# $1: cgroup file to wait for
+# $2: file to store the read result
+#
+wait_inotify()
+{
+ CGROUP_FILE=$1
+ OUTPUT_FILE=$2
+
+ $WAIT_INOTIFY $CGROUP_FILE
+ cat $CGROUP_FILE > $OUTPUT_FILE
+}
+
+#
+# Test if inotify events are properly generated when going into and out of
+# invalid partition state.
+#
+test_inotify()
+{
+ ERR=0
+ PRS=/tmp/.prs_$$
+ [[ -f $WAIT_INOTIFY ]] || {
+ echo "wait_inotify not found, inotify test SKIPPED."
+ return
+ }
+
+ pause 0.01
+ echo 1 > cpuset.cpus
+ echo 0 > cgroup.procs
+ echo root > cpuset.cpus.partition
+ pause 0.01
+ rm -f $PRS
+ wait_inotify $PWD/cpuset.cpus.partition $PRS &
+ pause 0.01
+ set_ctrl_state . "O1-0"
+ pause 0.01
+ check_cgroup_states ".:P-1"
+ if [[ $? -ne 0 ]]
+ then
+ echo "FAILED: Inotify test - partition not invalid"
+ ERR=1
+ elif [[ ! -f $PRS ]]
+ then
+ echo "FAILED: Inotify test - event not generated"
+ ERR=1
+ kill %1
+ elif [[ $(cat $PRS) != "root invalid"* ]]
+ then
+ echo "FAILED: Inotify test - incorrect state"
+ cat $PRS
+ ERR=1
+ fi
+ online_cpus
+ echo member > cpuset.cpus.partition
+ echo 0 > ../cgroup.procs
+ if [[ $ERR -ne 0 ]]
+ then
+ exit 1
+ else
+ echo "Inotify test PASSED"
+ fi
+}
+
+run_state_test TEST_MATRIX
+test_isolated
+test_inotify
+echo "All tests PASSED."
+cd ..
+rmdir test
diff --git a/tools/testing/selftests/cgroup/wait_inotify.c b/tools/testing/selftests/cgroup/wait_inotify.c
new file mode 100644
index 0000000000000..e11b431e1b620
--- /dev/null
+++ b/tools/testing/selftests/cgroup/wait_inotify.c
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Wait until an inotify event on the given cgroup file.
+ */
+#include <linux/limits.h>
+#include <sys/inotify.h>
+#include <sys/mman.h>
+#include <sys/ptrace.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <poll.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+static const char usage[] = "Usage: %s [-v] <cgroup_file>\n";
+static char *file;
+static int verbose;
+
+static inline void fail_message(char *msg)
+{
+ fprintf(stderr, msg, file);
+ exit(1);
+}
+
+int main(int argc, char *argv[])
+{
+ char *cmd = argv[0];
+ int c, fd;
+ struct pollfd fds = { .events = POLLIN, };
+
+ while ((c = getopt(argc, argv, "v")) != -1) {
+ switch (c) {
+ case 'v':
+ verbose++;
+ break;
+ }
+ argv++, argc--;
+ }
+
+ if (argc != 2) {
+ fprintf(stderr, usage, cmd);
+ return -1;
+ }
+ file = argv[1];
+ fd = open(file, O_RDONLY);
+ if (fd < 0)
+ fail_message("Cgroup file %s not found!\n");
+ close(fd);
+
+ fd = inotify_init();
+ if (fd < 0)
+ fail_message("inotify_init() fails on %s!\n");
+ if (inotify_add_watch(fd, file, IN_MODIFY) < 0)
+ fail_message("inotify_add_watch() fails on %s!\n");
+ fds.fd = fd;
+
+ /*
+ * poll waiting loop
+ */
+ for (;;) {
+ int ret = poll(&fds, 1, 10000);
+
+ if (ret < 0) {
+ if (errno == EINTR)
+ continue;
+ perror("poll");
+ exit(1);
+ }
+ if ((ret > 0) && (fds.revents & POLLIN))
+ break;
+ }
+ if (verbose) {
+ struct inotify_event events[10];
+ long len;
+
+ usleep(1000);
+ len = read(fd, events, sizeof(events));
+ printf("Number of events read = %ld\n",
+ len/sizeof(struct inotify_event));
+ }
+ close(fd);
+ return 0;
+}
From 0083d27b21dd2a598df8275b98f89ced532e2e53 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Tue, 6 Sep 2022 09:38:42 -1000
Subject: [PATCH 19/25] cgroup: Improve cftype add/rm error handling
Let's track whether a cftype is currently added or not using a new flag
__CFTYPE_ADDED so that duplicate operations can be failed safely and
consistently allow using empty cftypes.
Signed-off-by: Tejun Heo <tj@kernel.org>
---
include/linux/cgroup-defs.h | 1 +
kernel/cgroup/cgroup.c | 27 ++++++++++++++++++++-------
2 files changed, 21 insertions(+), 7 deletions(-)
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 1283993d7ea8f..9fa1652d04931 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -131,6 +131,7 @@ enum {
/* internal flags, do not use outside cgroup core proper */
__CFTYPE_ONLY_ON_DFL = (1 << 16), /* only on default hierarchy */
__CFTYPE_NOT_ON_DFL = (1 << 17), /* not on default hierarchy */
+ __CFTYPE_ADDED = (1 << 18),
};
/*
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index e0b72eb5d283b..bd9fe6e88320d 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -4198,19 +4198,26 @@ static void cgroup_exit_cftypes(struct cftype *cfts)
cft->ss = NULL;
/* revert flags set by cgroup core while adding @cfts */
- cft->flags &= ~(__CFTYPE_ONLY_ON_DFL | __CFTYPE_NOT_ON_DFL);
+ cft->flags &= ~(__CFTYPE_ONLY_ON_DFL | __CFTYPE_NOT_ON_DFL |
+ __CFTYPE_ADDED);
}
}
static int cgroup_init_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
{
struct cftype *cft;
+ int ret = 0;
for (cft = cfts; cft->name[0] != '\0'; cft++) {
struct kernfs_ops *kf_ops;
WARN_ON(cft->ss || cft->kf_ops);
+ if (cft->flags & __CFTYPE_ADDED) {
+ ret = -EBUSY;
+ break;
+ }
+
if ((cft->flags & CFTYPE_PRESSURE) && !cgroup_psi_enabled())
continue;
@@ -4226,26 +4233,26 @@ static int cgroup_init_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
if (cft->max_write_len && cft->max_write_len != PAGE_SIZE) {
kf_ops = kmemdup(kf_ops, sizeof(*kf_ops), GFP_KERNEL);
if (!kf_ops) {
- cgroup_exit_cftypes(cfts);
- return -ENOMEM;
+ ret = -ENOMEM;
+ break;
}
kf_ops->atomic_write_len = cft->max_write_len;
}
cft->kf_ops = kf_ops;
cft->ss = ss;
+ cft->flags |= __CFTYPE_ADDED;
}
- return 0;
+ if (ret)
+ cgroup_exit_cftypes(cfts);
+ return ret;
}
static int cgroup_rm_cftypes_locked(struct cftype *cfts)
{
lockdep_assert_held(&cgroup_mutex);
- if (!cfts || !cfts[0].ss)
- return -ENOENT;
-
list_del(&cfts->node);
cgroup_apply_cftypes(cfts, false);
cgroup_exit_cftypes(cfts);
@@ -4267,6 +4274,12 @@ int cgroup_rm_cftypes(struct cftype *cfts)
{
int ret;
+ if (!cfts || cfts[0].name[0] == '\0')
+ return 0;
+
+ if (!(cfts[0].flags & __CFTYPE_ADDED))
+ return -ENOENT;
+
mutex_lock(&cgroup_mutex);
ret = cgroup_rm_cftypes_locked(cfts);
mutex_unlock(&cgroup_mutex);
From 8a693f7766f9e27c390c5fec8a5db1f9d1d8177e Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Tue, 6 Sep 2022 09:38:55 -1000
Subject: [PATCH 20/25] cgroup: Remove CFTYPE_PRESSURE
CFTYPE_PRESSURE is used to flag PSI related files so that they are not
created if PSI is disabled during boot. It's a bit weird to use a generic
flag to mark a specific file type. Let's instead move the PSI files into its
own cftypes array and add/rm them conditionally. This is a bit more code but
cleaner.
No userland visible changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
---
include/linux/cgroup-defs.h | 1 -
kernel/cgroup/cgroup.c | 64 +++++++++++++++++++++----------------
2 files changed, 37 insertions(+), 28 deletions(-)
diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 9fa1652d04931..8f481d1b159af 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -126,7 +126,6 @@ enum {
CFTYPE_NO_PREFIX = (1 << 3), /* (DON'T USE FOR NEW FILES) no subsys prefix */
CFTYPE_WORLD_WRITABLE = (1 << 4), /* (DON'T USE FOR NEW FILES) S_IWUGO */
CFTYPE_DEBUG = (1 << 5), /* create when cgroup_debug */
- CFTYPE_PRESSURE = (1 << 6), /* only if pressure feature is enabled */
/* internal flags, do not use outside cgroup core proper */
__CFTYPE_ONLY_ON_DFL = (1 << 16), /* only on default hierarchy */
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index bd9fe6e88320d..e24015877d3c5 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -217,6 +217,7 @@ struct cgroup_namespace init_cgroup_ns = {
static struct file_system_type cgroup2_fs_type;
static struct cftype cgroup_base_files[];
+static struct cftype cgroup_psi_files[];
/* cgroup optional features */
enum cgroup_opt_features {
@@ -1689,12 +1690,16 @@ static void css_clear_dir(struct cgroup_subsys_state *css)
css->flags &= ~CSS_VISIBLE;
if (!css->ss) {
- if (cgroup_on_dfl(cgrp))
- cfts = cgroup_base_files;
- else
- cfts = cgroup1_base_files;
-
- cgroup_addrm_files(css, cgrp, cfts, false);
+ if (cgroup_on_dfl(cgrp)) {
+ cgroup_addrm_files(css, cgrp,
+ cgroup_base_files, false);
+ if (cgroup_psi_enabled())
+ cgroup_addrm_files(css, cgrp,
+ cgroup_psi_files, false);
+ } else {
+ cgroup_addrm_files(css, cgrp,
+ cgroup1_base_files, false);
+ }
} else {
list_for_each_entry(cfts, &css->ss->cfts, node)
cgroup_addrm_files(css, cgrp, cfts, false);
@@ -1717,14 +1722,22 @@ static int css_populate_dir(struct cgroup_subsys_state *css)
return 0;
if (!css->ss) {
- if (cgroup_on_dfl(cgrp))
- cfts = cgroup_base_files;
- else
- cfts = cgroup1_base_files;
-
- ret = cgroup_addrm_files(&cgrp->self, cgrp, cfts, true);
- if (ret < 0)
- return ret;
+ if (cgroup_on_dfl(cgrp)) {
+ ret = cgroup_addrm_files(&cgrp->self, cgrp,
+ cgroup_base_files, true);
+ if (ret < 0)
+ return ret;
+
+ if (cgroup_psi_enabled()) {
+ ret = cgroup_addrm_files(&cgrp->self, cgrp,
+ cgroup_psi_files, true);
+ if (ret < 0)
+ return ret;
+ }
+ } else {
+ cgroup_addrm_files(css, cgrp,
+ cgroup1_base_files, true);
+ }
} else {
list_for_each_entry(cfts, &css->ss->cfts, node) {
ret = cgroup_addrm_files(css, cgrp, cfts, true);
@@ -4132,8 +4145,6 @@ static int cgroup_addrm_files(struct cgroup_subsys_state *css,
restart:
for (cft = cfts; cft != cft_end && cft->name[0] != '\0'; cft++) {
/* does cft->flags tell us to skip this file on @cgrp? */
- if ((cft->flags & CFTYPE_PRESSURE) && !cgroup_psi_enabled())
- continue;
if ((cft->flags & __CFTYPE_ONLY_ON_DFL) && !cgroup_on_dfl(cgrp))
continue;
if ((cft->flags & __CFTYPE_NOT_ON_DFL) && cgroup_on_dfl(cgrp))
@@ -4218,9 +4229,6 @@ static int cgroup_init_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
break;
}
- if ((cft->flags & CFTYPE_PRESSURE) && !cgroup_psi_enabled())
- continue;
-
if (cft->seq_start)
kf_ops = &cgroup_kf_ops;
else
@@ -5144,10 +5152,13 @@ static struct cftype cgroup_base_files[] = {
.name = "cpu.stat",
.seq_show = cpu_stat_show,
},
+ { } /* terminate */
+};
+
+static struct cftype cgroup_psi_files[] = {
#ifdef CONFIG_PSI
{
.name = "io.pressure",
- .flags = CFTYPE_PRESSURE,
.seq_show = cgroup_io_pressure_show,
.write = cgroup_io_pressure_write,
.poll = cgroup_pressure_poll,
@@ -5155,7 +5166,6 @@ static struct cftype cgroup_base_files[] = {
},
{
.name = "memory.pressure",
- .flags = CFTYPE_PRESSURE,
.seq_show = cgroup_memory_pressure_show,
.write = cgroup_memory_pressure_write,
.poll = cgroup_pressure_poll,
@@ -5163,7 +5173,6 @@ static struct cftype cgroup_base_files[] = {
},
{
.name = "cpu.pressure",
- .flags = CFTYPE_PRESSURE,
.seq_show = cgroup_cpu_pressure_show,
.write = cgroup_cpu_pressure_write,
.poll = cgroup_pressure_poll,
@@ -5930,6 +5939,7 @@ int __init cgroup_init(void)
BUILD_BUG_ON(CGROUP_SUBSYS_COUNT > 16);
BUG_ON(cgroup_init_cftypes(NULL, cgroup_base_files));
+ BUG_ON(cgroup_init_cftypes(NULL, cgroup_psi_files));
BUG_ON(cgroup_init_cftypes(NULL, cgroup1_base_files));
cgroup_rstat_boot();
@@ -6821,9 +6831,6 @@ static ssize_t show_delegatable_files(struct cftype *files, char *buf,
if (!(cft->flags & CFTYPE_NS_DELEGATABLE))
continue;
- if ((cft->flags & CFTYPE_PRESSURE) && !cgroup_psi_enabled())
- continue;
-
if (prefix)
ret += snprintf(buf + ret, size - ret, "%s.", prefix);
@@ -6843,8 +6850,11 @@ static ssize_t delegate_show(struct kobject *kobj, struct kobj_attribute *attr,
int ssid;
ssize_t ret = 0;
- ret = show_delegatable_files(cgroup_base_files, buf, PAGE_SIZE - ret,
- NULL);
+ ret = show_delegatable_files(cgroup_base_files, buf + ret,
+ PAGE_SIZE - ret, NULL);
+ if (cgroup_psi_enabled())
+ ret += show_delegatable_files(cgroup_psi_files, buf + ret,
+ PAGE_SIZE - ret, NULL);
for_each_subsys(ss, ssid)
ret += show_delegatable_files(ss->dfl_cftypes, buf + ret,
From c478bd88362418bd2a1c230215fde184f5642e44 Mon Sep 17 00:00:00 2001
From: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Date: Wed, 7 Sep 2022 12:01:12 +0800
Subject: [PATCH 21/25] cgroup/cpuset: remove unreachable code
The function sched_partition_show cannot execute seq_puts, delete the
invalid code.
kernel/cgroup/cpuset.c:2849 sched_partition_show() warn: ignoring unreachable code.
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=2087
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/cpuset.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 6baa977a71ba4..b474289c15b82 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -2846,8 +2846,6 @@ static int sched_partition_show(struct seq_file *seq, void *v)
else
seq_printf(seq, "%s invalid\n", type);
break;
- seq_puts(seq, "isolated invalid\n");
- break;
}
return 0;
}
From 7e1eb5437d3c3fdb61d45378579aab383cafc694 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Fri, 23 Sep 2022 07:23:06 -1000
Subject: [PATCH 22/25] cgroup: Make cgroup_get_from_id() prettier
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
After merging 836ac87d ("cgroup: fix cgroup_get_from_id") into for-6.1, its
combination with two commits in for-6.1 - 4534dee9 ("cgroup: cgroup: Honor
caller's cgroup NS when resolving cgroup id") and fa7e439c ("cgroup:
Homogenize cgroup_get_from_id() return value") - makes the gotos in the
error handling path too ugly while not adding anything of value.
All that the gotos are saving is one extra kernfs_put() call. Let's remove
the gotos and perform error returns directly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Michal Koutný <mkoutny@suse.com>
---
kernel/cgroup/cgroup.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 0d93cd17548c2..c1f1ef6090da8 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -6066,14 +6066,16 @@ void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
struct cgroup *cgroup_get_from_id(u64 id)
{
struct kernfs_node *kn;
- struct cgroup *cgrp = NULL, *root_cgrp;
+ struct cgroup *cgrp, *root_cgrp;
kn = kernfs_find_and_get_node_by_id(cgrp_dfl_root.kf_root, id);
if (!kn)
- goto out;
+ return ERR_PTR(-ENOENT);
- if (kernfs_type(kn) != KERNFS_DIR)
- goto put;
+ if (kernfs_type(kn) != KERNFS_DIR) {
+ kernfs_put(kn);
+ return ERR_PTR(-ENOENT);
+ }
rcu_read_lock();
@@ -6082,21 +6084,20 @@ struct cgroup *cgroup_get_from_id(u64 id)
cgrp = NULL;
rcu_read_unlock();
-put:
kernfs_put(kn);
if (!cgrp)
- goto out;
+ return ERR_PTR(-ENOENT);
spin_lock_irq(&css_set_lock);
root_cgrp = current_cgns_cgroup_from_root(&cgrp_dfl_root);
spin_unlock_irq(&css_set_lock);
if (!cgroup_is_descendant(cgrp, root_cgrp)) {
cgroup_put(cgrp);
- cgrp = NULL;
+ return ERR_PTR(-ENOENT);
}
-out:
- return cgrp ?: ERR_PTR(-ENOENT);
+
+ return cgrp;
}
EXPORT_SYMBOL_GPL(cgroup_get_from_id);
From 61c41711b12b808ec388b739444372430942c2e8 Mon Sep 17 00:00:00 2001
From: William Dean <williamsukatube@163.com>
Date: Sat, 17 Sep 2022 16:40:39 +0800
Subject: [PATCH 23/25] cgroup: simplify code in cgroup_apply_control
It could directly return 'cgroup_update_dfl_csses' to simplify code.
Signed-off-by: William Dean <williamsukatube@163.com>
Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/cgroup.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index c1f1ef6090da8..c37b8265c0a38 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -3305,11 +3305,7 @@ static int cgroup_apply_control(struct cgroup *cgrp)
* making the following cgroup_update_dfl_csses() properly update
* css associations of all tasks in the subtree.
*/
- ret = cgroup_update_dfl_csses(cgrp);
- if (ret)
- return ret;
-
- return 0;
+ return cgroup_update_dfl_csses(cgrp);
}
/**
From b74440d89895816660236be4433f0891e37d44eb Mon Sep 17 00:00:00 2001
From: Elijah Conners <business@elijahpepe.com>
Date: Tue, 30 Aug 2022 07:38:27 -0700
Subject: [PATCH 24/25] iocost_monitor: reorder BlkgIterator
In order to comply with PEP 8, the first parameter of a class should be
__init__.
Signed-off-by: Elijah Conners <business@elijahpepe.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
tools/cgroup/iocost_monitor.py | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/tools/cgroup/iocost_monitor.py b/tools/cgroup/iocost_monitor.py
index c4ff907c078b5..0dbbc67400fcb 100644
--- a/tools/cgroup/iocost_monitor.py
+++ b/tools/cgroup/iocost_monitor.py
@@ -61,6 +61,11 @@ def err(s):
}
class BlkgIterator:
+ def __init__(self, root_blkcg, q_id, include_dying=False):
+ self.include_dying = include_dying
+ self.blkgs = []
+ self.walk(root_blkcg, q_id, '')
+
def blkcg_name(blkcg):
return blkcg.css.cgroup.kn.name.string_().decode('utf-8')
@@ -82,11 +87,6 @@ def walk(self, blkcg, q_id, parent_path):
blkcg.css.children.address_of_(), 'css.sibling'):
self.walk(c, q_id, path)
- def __init__(self, root_blkcg, q_id, include_dying=False):
- self.include_dying = include_dying
- self.blkgs = []
- self.walk(root_blkcg, q_id, '')
-
def __iter__(self):
return iter(self.blkgs)
From 8619e94d3be376bb5e8f20988c0e6e3309d2b09a Mon Sep 17 00:00:00 2001
From: ye xingchen <ye.xingchen@zte.com.cn>
Date: Wed, 21 Sep 2022 09:35:17 +0000
Subject: [PATCH 25/25] cgroup: use strscpy() is more robust and safer
The implementation of strscpy() is more robust and safer.
That's now the recommended way to copy NUL terminated strings.
Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
kernel/cgroup/cgroup.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index c37b8265c0a38..151c55d2e0160 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -2374,7 +2374,7 @@ int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
ret = cgroup_path_ns_locked(cgrp, buf, buflen, &init_cgroup_ns);
} else {
/* if no hierarchy exists, everyone is in "/" */
- ret = strlcpy(buf, "/", buflen);
+ ret = strscpy(buf, "/", buflen);
}
spin_unlock_irq(&css_set_lock);