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yaml
---
r: 281467
b: refs/heads/master
c: 2f7ee56
h: refs/heads/master
i:
  281465: 174195d
  281463: aa8a15c
v: v3
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Tejun Heo committed Dec 13, 2011
1 parent a1ac813 commit 87df04d
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Showing 8 changed files with 159 additions and 44 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 134d33737f9015761c3832f6b268fae6274aac7f
refs/heads/master: 2f7ee5691eecb67c8108b92001a85563ea336ac5
31 changes: 21 additions & 10 deletions trunk/Documentation/cgroups/cgroups.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -594,15 +594,25 @@ rmdir() will fail with it. From this behavior, pre_destroy() can be
called multiple times against a cgroup.

int can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct task_struct *task)
struct cgroup_taskset *tset)
(cgroup_mutex held by caller)

Called prior to moving a task into a cgroup; if the subsystem
returns an error, this will abort the attach operation. If a NULL
task is passed, then a successful result indicates that *any*
unspecified task can be moved into the cgroup. Note that this isn't
called on a fork. If this method returns 0 (success) then this should
remain valid while the caller holds cgroup_mutex and it is ensured that either
Called prior to moving one or more tasks into a cgroup; if the
subsystem returns an error, this will abort the attach operation.
@tset contains the tasks to be attached and is guaranteed to have at
least one task in it.

If there are multiple tasks in the taskset, then:
- it's guaranteed that all are from the same thread group
- @tset contains all tasks from the thread group whether or not
they're switching cgroups
- the first task is the leader

Each @tset entry also contains the task's old cgroup and tasks which
aren't switching cgroup can be skipped easily using the
cgroup_taskset_for_each() iterator. Note that this isn't called on a
fork. If this method returns 0 (success) then this should remain valid
while the caller holds cgroup_mutex and it is ensured that either
attach() or cancel_attach() will be called in future.

int can_attach_task(struct cgroup *cgrp, struct task_struct *tsk);
Expand All @@ -613,14 +623,14 @@ attached (possibly many when using cgroup_attach_proc). Called after
can_attach.

void cancel_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct task_struct *task, bool threadgroup)
struct cgroup_taskset *tset)
(cgroup_mutex held by caller)

Called when a task attach operation has failed after can_attach() has succeeded.
A subsystem whose can_attach() has some side-effects should provide this
function, so that the subsystem can implement a rollback. If not, not necessary.
This will be called only about subsystems whose can_attach() operation have
succeeded.
succeeded. The parameters are identical to can_attach().

void pre_attach(struct cgroup *cgrp);
(cgroup_mutex held by caller)
Expand All @@ -629,11 +639,12 @@ For any non-per-thread attachment work that needs to happen before
attach_task. Needed by cpuset.

void attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct cgroup *old_cgrp, struct task_struct *task)
struct cgroup_taskset *tset)
(cgroup_mutex held by caller)

Called after the task has been attached to the cgroup, to allow any
post-attachment activity that requires memory allocations or blocking.
The parameters are identical to can_attach().

void attach_task(struct cgroup *cgrp, struct task_struct *tsk);
(cgroup_mutex held by caller)
Expand Down
28 changes: 25 additions & 3 deletions trunk/include/linux/cgroup.h
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Original file line number Diff line number Diff line change
Expand Up @@ -456,6 +456,28 @@ int cgroup_is_descendant(const struct cgroup *cgrp, struct task_struct *task);
void cgroup_exclude_rmdir(struct cgroup_subsys_state *css);
void cgroup_release_and_wakeup_rmdir(struct cgroup_subsys_state *css);

/*
* Control Group taskset, used to pass around set of tasks to cgroup_subsys
* methods.
*/
struct cgroup_taskset;
struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset);
struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset);
struct cgroup *cgroup_taskset_cur_cgroup(struct cgroup_taskset *tset);
int cgroup_taskset_size(struct cgroup_taskset *tset);

/**
* cgroup_taskset_for_each - iterate cgroup_taskset
* @task: the loop cursor
* @skip_cgrp: skip if task's cgroup matches this, %NULL to iterate through all
* @tset: taskset to iterate
*/
#define cgroup_taskset_for_each(task, skip_cgrp, tset) \
for ((task) = cgroup_taskset_first((tset)); (task); \
(task) = cgroup_taskset_next((tset))) \
if (!(skip_cgrp) || \
cgroup_taskset_cur_cgroup((tset)) != (skip_cgrp))

/*
* Control Group subsystem type.
* See Documentation/cgroups/cgroups.txt for details
Expand All @@ -467,14 +489,14 @@ struct cgroup_subsys {
int (*pre_destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp);
void (*destroy)(struct cgroup_subsys *ss, struct cgroup *cgrp);
int (*can_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct task_struct *tsk);
struct cgroup_taskset *tset);
int (*can_attach_task)(struct cgroup *cgrp, struct task_struct *tsk);
void (*cancel_attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct task_struct *tsk);
struct cgroup_taskset *tset);
void (*pre_attach)(struct cgroup *cgrp);
void (*attach_task)(struct cgroup *cgrp, struct task_struct *tsk);
void (*attach)(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct cgroup *old_cgrp, struct task_struct *tsk);
struct cgroup_taskset *tset);
void (*fork)(struct cgroup_subsys *ss, struct task_struct *task);
void (*exit)(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct cgroup *old_cgrp, struct task_struct *task);
Expand Down
99 changes: 89 additions & 10 deletions trunk/kernel/cgroup.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1757,11 +1757,85 @@ int cgroup_path(const struct cgroup *cgrp, char *buf, int buflen)
}
EXPORT_SYMBOL_GPL(cgroup_path);

/*
* Control Group taskset
*/
struct task_and_cgroup {
struct task_struct *task;
struct cgroup *cgrp;
};

struct cgroup_taskset {
struct task_and_cgroup single;
struct flex_array *tc_array;
int tc_array_len;
int idx;
struct cgroup *cur_cgrp;
};

/**
* cgroup_taskset_first - reset taskset and return the first task
* @tset: taskset of interest
*
* @tset iteration is initialized and the first task is returned.
*/
struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset)
{
if (tset->tc_array) {
tset->idx = 0;
return cgroup_taskset_next(tset);
} else {
tset->cur_cgrp = tset->single.cgrp;
return tset->single.task;
}
}
EXPORT_SYMBOL_GPL(cgroup_taskset_first);

/**
* cgroup_taskset_next - iterate to the next task in taskset
* @tset: taskset of interest
*
* Return the next task in @tset. Iteration must have been initialized
* with cgroup_taskset_first().
*/
struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset)
{
struct task_and_cgroup *tc;

if (!tset->tc_array || tset->idx >= tset->tc_array_len)
return NULL;

tc = flex_array_get(tset->tc_array, tset->idx++);
tset->cur_cgrp = tc->cgrp;
return tc->task;
}
EXPORT_SYMBOL_GPL(cgroup_taskset_next);

/**
* cgroup_taskset_cur_cgroup - return the matching cgroup for the current task
* @tset: taskset of interest
*
* Return the cgroup for the current (last returned) task of @tset. This
* function must be preceded by either cgroup_taskset_first() or
* cgroup_taskset_next().
*/
struct cgroup *cgroup_taskset_cur_cgroup(struct cgroup_taskset *tset)
{
return tset->cur_cgrp;
}
EXPORT_SYMBOL_GPL(cgroup_taskset_cur_cgroup);

/**
* cgroup_taskset_size - return the number of tasks in taskset
* @tset: taskset of interest
*/
int cgroup_taskset_size(struct cgroup_taskset *tset)
{
return tset->tc_array ? tset->tc_array_len : 1;
}
EXPORT_SYMBOL_GPL(cgroup_taskset_size);


/*
* cgroup_task_migrate - move a task from one cgroup to another.
*
Expand Down Expand Up @@ -1842,6 +1916,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
struct cgroup_subsys *ss, *failed_ss = NULL;
struct cgroup *oldcgrp;
struct cgroupfs_root *root = cgrp->root;
struct cgroup_taskset tset = { };

/* @tsk either already exited or can't exit until the end */
if (tsk->flags & PF_EXITING)
Expand All @@ -1852,9 +1927,12 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
if (cgrp == oldcgrp)
return 0;

tset.single.task = tsk;
tset.single.cgrp = oldcgrp;

for_each_subsys(root, ss) {
if (ss->can_attach) {
retval = ss->can_attach(ss, cgrp, tsk);
retval = ss->can_attach(ss, cgrp, &tset);
if (retval) {
/*
* Remember on which subsystem the can_attach()
Expand Down Expand Up @@ -1885,7 +1963,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
if (ss->attach_task)
ss->attach_task(cgrp, tsk);
if (ss->attach)
ss->attach(ss, cgrp, oldcgrp, tsk);
ss->attach(ss, cgrp, &tset);
}

synchronize_rcu();
Expand All @@ -1907,7 +1985,7 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk)
*/
break;
if (ss->cancel_attach)
ss->cancel_attach(ss, cgrp, tsk);
ss->cancel_attach(ss, cgrp, &tset);
}
}
return retval;
Expand Down Expand Up @@ -2023,6 +2101,7 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
struct task_struct *tsk;
struct task_and_cgroup *tc;
struct flex_array *group;
struct cgroup_taskset tset = { };
/*
* we need to make sure we have css_sets for all the tasks we're
* going to move -before- we actually start moving them, so that in
Expand Down Expand Up @@ -2089,6 +2168,8 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
} while_each_thread(leader, tsk);
/* remember the number of threads in the array for later. */
group_size = i;
tset.tc_array = group;
tset.tc_array_len = group_size;
read_unlock(&tasklist_lock);

/* methods shouldn't be called if no task is actually migrating */
Expand All @@ -2101,7 +2182,7 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
*/
for_each_subsys(root, ss) {
if (ss->can_attach) {
retval = ss->can_attach(ss, cgrp, leader);
retval = ss->can_attach(ss, cgrp, &tset);
if (retval) {
failed_ss = ss;
goto out_cancel_attach;
Expand Down Expand Up @@ -2183,10 +2264,8 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
* being moved, this call will need to be reworked to communicate that.
*/
for_each_subsys(root, ss) {
if (ss->attach) {
tc = flex_array_get(group, 0);
ss->attach(ss, cgrp, tc->cgrp, tc->task);
}
if (ss->attach)
ss->attach(ss, cgrp, &tset);
}

/*
Expand All @@ -2208,11 +2287,11 @@ int cgroup_attach_proc(struct cgroup *cgrp, struct task_struct *leader)
for_each_subsys(root, ss) {
if (ss == failed_ss) {
if (cancel_failed_ss && ss->cancel_attach)
ss->cancel_attach(ss, cgrp, leader);
ss->cancel_attach(ss, cgrp, &tset);
break;
}
if (ss->cancel_attach)
ss->cancel_attach(ss, cgrp, leader);
ss->cancel_attach(ss, cgrp, &tset);
}
}
out_put_tasks:
Expand Down
2 changes: 1 addition & 1 deletion trunk/kernel/cgroup_freezer.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -159,7 +159,7 @@ static void freezer_destroy(struct cgroup_subsys *ss,
*/
static int freezer_can_attach(struct cgroup_subsys *ss,
struct cgroup *new_cgroup,
struct task_struct *task)
struct cgroup_taskset *tset)
{
struct freezer *freezer;

Expand Down
18 changes: 10 additions & 8 deletions trunk/kernel/cpuset.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1371,10 +1371,10 @@ static int fmeter_getrate(struct fmeter *fmp)
}

/* Called by cgroups to determine if a cpuset is usable; cgroup_mutex held */
static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cont,
struct task_struct *tsk)
static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct cgroup_taskset *tset)
{
struct cpuset *cs = cgroup_cs(cont);
struct cpuset *cs = cgroup_cs(cgrp);

if (cpumask_empty(cs->cpus_allowed) || nodes_empty(cs->mems_allowed))
return -ENOSPC;
Expand All @@ -1387,7 +1387,7 @@ static int cpuset_can_attach(struct cgroup_subsys *ss, struct cgroup *cont,
* set_cpus_allowed_ptr() on all attached tasks before cpus_allowed may
* be changed.
*/
if (tsk->flags & PF_THREAD_BOUND)
if (cgroup_taskset_first(tset)->flags & PF_THREAD_BOUND)
return -EINVAL;

return 0;
Expand Down Expand Up @@ -1437,12 +1437,14 @@ static void cpuset_attach_task(struct cgroup *cont, struct task_struct *tsk)
cpuset_update_task_spread_flag(cs, tsk);
}

static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cont,
struct cgroup *oldcont, struct task_struct *tsk)
static void cpuset_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
struct cgroup_taskset *tset)
{
struct mm_struct *mm;
struct cpuset *cs = cgroup_cs(cont);
struct cpuset *oldcs = cgroup_cs(oldcont);
struct task_struct *tsk = cgroup_taskset_first(tset);
struct cgroup *oldcgrp = cgroup_taskset_cur_cgroup(tset);
struct cpuset *cs = cgroup_cs(cgrp);
struct cpuset *oldcs = cgroup_cs(oldcgrp);

/*
* Change mm, possibly for multiple threads in a threadgroup. This is
Expand Down
16 changes: 8 additions & 8 deletions trunk/mm/memcontrol.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5298,8 +5298,9 @@ static void mem_cgroup_clear_mc(void)

static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
struct cgroup *cgroup,
struct task_struct *p)
struct cgroup_taskset *tset)
{
struct task_struct *p = cgroup_taskset_first(tset);
int ret = 0;
struct mem_cgroup *memcg = mem_cgroup_from_cont(cgroup);

Expand Down Expand Up @@ -5337,7 +5338,7 @@ static int mem_cgroup_can_attach(struct cgroup_subsys *ss,

static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
struct cgroup *cgroup,
struct task_struct *p)
struct cgroup_taskset *tset)
{
mem_cgroup_clear_mc();
}
Expand Down Expand Up @@ -5454,9 +5455,9 @@ static void mem_cgroup_move_charge(struct mm_struct *mm)

static void mem_cgroup_move_task(struct cgroup_subsys *ss,
struct cgroup *cont,
struct cgroup *old_cont,
struct task_struct *p)
struct cgroup_taskset *tset)
{
struct task_struct *p = cgroup_taskset_first(tset);
struct mm_struct *mm = get_task_mm(p);

if (mm) {
Expand All @@ -5471,19 +5472,18 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
#else /* !CONFIG_MMU */
static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
struct cgroup *cgroup,
struct task_struct *p)
struct cgroup_taskset *tset)
{
return 0;
}
static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
struct cgroup *cgroup,
struct task_struct *p)
struct cgroup_taskset *tset)
{
}
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
struct cgroup *cont,
struct cgroup *old_cont,
struct task_struct *p)
struct cgroup_taskset *tset)
{
}
#endif
Expand Down
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