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memcg: remove cgroup_event->cft
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The only use of cgroup_event->cft is distinguishing "usage_in_bytes"
and "memsw.usgae_in_bytes" for mem_cgroup_usage_[un]register_event(),
which can be done by adding an explicit argument to the function and
implementing two wrappers so that the two cases can be distinguished
from the function alone.

Remove cgroup_event->cft and the related code including
[un]register_events() methods.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.cz>
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Tejun Heo committed Nov 22, 2013
1 parent fba9480 commit 347c4a8
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Showing 3 changed files with 38 additions and 43 deletions.
2 changes: 0 additions & 2 deletions include/linux/vmpressure.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -36,11 +36,9 @@ extern struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg);
extern struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr);
extern struct vmpressure *css_to_vmpressure(struct cgroup_subsys_state *css);
extern int vmpressure_register_event(struct cgroup_subsys_state *css,
struct cftype *cft,
struct eventfd_ctx *eventfd,
const char *args);
extern void vmpressure_unregister_event(struct cgroup_subsys_state *css,
struct cftype *cft,
struct eventfd_ctx *eventfd);
#else
static inline void vmpressure(gfp_t gfp, struct mem_cgroup *memcg,
Expand Down
65 changes: 35 additions & 30 deletions mm/memcontrol.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -236,10 +236,6 @@ struct cgroup_event {
* css which the event belongs to.
*/
struct cgroup_subsys_state *css;
/*
* Control file which the event associated.
*/
struct cftype *cft;
/*
* eventfd to signal userspace about the event.
*/
Expand All @@ -254,15 +250,13 @@ struct cgroup_event {
* on eventfd to send notification to userspace.
*/
int (*register_event)(struct cgroup_subsys_state *css,
struct cftype *cft, struct eventfd_ctx *eventfd,
const char *args);
struct eventfd_ctx *eventfd, const char *args);
/*
* unregister_event() callback will be called when userspace closes
* the eventfd or on cgroup removing. This callback must be set,
* if you want provide notification functionality.
*/
void (*unregister_event)(struct cgroup_subsys_state *css,
struct cftype *cft,
struct eventfd_ctx *eventfd);
/*
* All fields below needed to unregister event when
Expand Down Expand Up @@ -5688,13 +5682,12 @@ static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
mem_cgroup_oom_notify_cb(iter);
}

static int mem_cgroup_usage_register_event(struct cgroup_subsys_state *css,
struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
static int __mem_cgroup_usage_register_event(struct cgroup_subsys_state *css,
struct eventfd_ctx *eventfd, const char *args, enum res_type type)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct mem_cgroup_thresholds *thresholds;
struct mem_cgroup_threshold_ary *new;
enum res_type type = MEMFILE_TYPE(cft->private);
u64 threshold, usage;
int i, size, ret;

Expand Down Expand Up @@ -5771,13 +5764,24 @@ static int mem_cgroup_usage_register_event(struct cgroup_subsys_state *css,
return ret;
}

static void mem_cgroup_usage_unregister_event(struct cgroup_subsys_state *css,
struct cftype *cft, struct eventfd_ctx *eventfd)
static int mem_cgroup_usage_register_event(struct cgroup_subsys_state *css,
struct eventfd_ctx *eventfd, const char *args)
{
return __mem_cgroup_usage_register_event(css, eventfd, args, _MEM);
}

static int memsw_cgroup_usage_register_event(struct cgroup_subsys_state *css,
struct eventfd_ctx *eventfd, const char *args)
{
return __mem_cgroup_usage_register_event(css, eventfd, args, _MEMSWAP);
}

static void __mem_cgroup_usage_unregister_event(struct cgroup_subsys_state *css,
struct eventfd_ctx *eventfd, enum res_type type)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct mem_cgroup_thresholds *thresholds;
struct mem_cgroup_threshold_ary *new;
enum res_type type = MEMFILE_TYPE(cft->private);
u64 usage;
int i, j, size;

Expand Down Expand Up @@ -5850,14 +5854,24 @@ static void mem_cgroup_usage_unregister_event(struct cgroup_subsys_state *css,
mutex_unlock(&memcg->thresholds_lock);
}

static void mem_cgroup_usage_unregister_event(struct cgroup_subsys_state *css,
struct eventfd_ctx *eventfd)
{
return __mem_cgroup_usage_unregister_event(css, eventfd, _MEM);
}

static void memsw_cgroup_usage_unregister_event(struct cgroup_subsys_state *css,
struct eventfd_ctx *eventfd)
{
return __mem_cgroup_usage_unregister_event(css, eventfd, _MEMSWAP);
}

static int mem_cgroup_oom_register_event(struct cgroup_subsys_state *css,
struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
struct eventfd_ctx *eventfd, const char *args)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct mem_cgroup_eventfd_list *event;
enum res_type type = MEMFILE_TYPE(cft->private);

BUG_ON(type != _OOM_TYPE);
event = kmalloc(sizeof(*event), GFP_KERNEL);
if (!event)
return -ENOMEM;
Expand All @@ -5876,13 +5890,10 @@ static int mem_cgroup_oom_register_event(struct cgroup_subsys_state *css,
}

static void mem_cgroup_oom_unregister_event(struct cgroup_subsys_state *css,
struct cftype *cft, struct eventfd_ctx *eventfd)
struct eventfd_ctx *eventfd)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
struct mem_cgroup_eventfd_list *ev, *tmp;
enum res_type type = MEMFILE_TYPE(cft->private);

BUG_ON(type != _OOM_TYPE);

spin_lock(&memcg_oom_lock);

Expand Down Expand Up @@ -6012,7 +6023,7 @@ static void cgroup_event_remove(struct work_struct *work)

remove_wait_queue(event->wqh, &event->wait);

event->unregister_event(css, event->cft, event->eventfd);
event->unregister_event(css, event->eventfd);

/* Notify userspace the event is going away. */
eventfd_signal(event->eventfd, 1);
Expand Down Expand Up @@ -6133,12 +6144,6 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css,
if (ret < 0)
goto out_put_cfile;

event->cft = __file_cft(cfile.file);
if (IS_ERR(event->cft)) {
ret = PTR_ERR(event->cft);
goto out_put_cfile;
}

/*
* Determine the event callbacks and set them in @event. This used
* to be done via struct cftype but cgroup core no longer knows
Expand All @@ -6157,8 +6162,8 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css,
event->register_event = vmpressure_register_event;
event->unregister_event = vmpressure_unregister_event;
} else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
event->register_event = mem_cgroup_usage_register_event;
event->unregister_event = mem_cgroup_usage_unregister_event;
event->register_event = memsw_cgroup_usage_register_event;
event->unregister_event = memsw_cgroup_usage_unregister_event;
} else {
ret = -EINVAL;
goto out_put_cfile;
Expand All @@ -6181,7 +6186,7 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css,
if (ret)
goto out_put_cfile;

ret = event->register_event(css, event->cft, event->eventfd, buffer);
ret = event->register_event(css, event->eventfd, buffer);
if (ret)
goto out_put_css;

Expand Down
14 changes: 3 additions & 11 deletions mm/vmpressure.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -279,7 +279,6 @@ void vmpressure_prio(gfp_t gfp, struct mem_cgroup *memcg, int prio)
/**
* vmpressure_register_event() - Bind vmpressure notifications to an eventfd
* @css: css that is interested in vmpressure notifications
* @cft: cgroup control files handle
* @eventfd: eventfd context to link notifications with
* @args: event arguments (used to set up a pressure level threshold)
*
Expand All @@ -289,13 +288,10 @@ void vmpressure_prio(gfp_t gfp, struct mem_cgroup *memcg, int prio)
* threshold (one of vmpressure_str_levels, i.e. "low", "medium", or
* "critical").
*
* This function should not be used directly, just pass it to (struct
* cftype).register_event, and then cgroup core will handle everything by
* itself.
* To be used as memcg event method.
*/
int vmpressure_register_event(struct cgroup_subsys_state *css,
struct cftype *cft, struct eventfd_ctx *eventfd,
const char *args)
struct eventfd_ctx *eventfd, const char *args)
{
struct vmpressure *vmpr = css_to_vmpressure(css);
struct vmpressure_event *ev;
Expand Down Expand Up @@ -326,19 +322,15 @@ int vmpressure_register_event(struct cgroup_subsys_state *css,
/**
* vmpressure_unregister_event() - Unbind eventfd from vmpressure
* @css: css handle
* @cft: cgroup control files handle
* @eventfd: eventfd context that was used to link vmpressure with the @cg
*
* This function does internal manipulations to detach the @eventfd from
* the vmpressure notifications, and then frees internal resources
* associated with the @eventfd (but the @eventfd itself is not freed).
*
* This function should not be used directly, just pass it to (struct
* cftype).unregister_event, and then cgroup core will handle everything
* by itself.
* To be used as memcg event method.
*/
void vmpressure_unregister_event(struct cgroup_subsys_state *css,
struct cftype *cft,
struct eventfd_ctx *eventfd)
{
struct vmpressure *vmpr = css_to_vmpressure(css);
Expand Down

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