From fba94807837850e211f8975e1970e23e7804ff4d Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 22 Nov 2013 18:20:43 -0500 Subject: [PATCH] cgroup, memcg: move cgroup->event_list[_lock] and event callbacks into memcg cgroup_event is being moved from cgroup core to memcg and the implementation is already moved by the previous patch. This patch moves the data fields and callbacks. * cgroup->event_list[_lock] are moved to mem_cgroup. * cftype->[un]register_event() are moved to cgroup_event. This makes it impossible for individual cftype definitions to specify their event callbacks. This is worked around by simply hard-coding filename to event callback mapping in cgroup_write_event_control(). This is awkward and inflexible, which is actually desirable given that we don't want to grow more usages of this feature. * eventfd_ctx declaration is removed from cgroup.h, which makes vmpressure.h miss eventfd_ctx declaration. Include eventfd.h from vmpressure.h. v2: Use file name from dentry instead of cftype. This will allow removing all cftype handling in the function. Signed-off-by: Tejun Heo Acked-by: Li Zefan Acked-by: Kirill A. Shutemov Acked-by: Michal Hocko Cc: Johannes Weiner Cc: Balbir Singh --- include/linux/cgroup.h | 24 ------------- include/linux/vmpressure.h | 1 + kernel/cgroup.c | 2 -- mm/memcontrol.c | 87 ++++++++++++++++++++++++++++++++-------------- 4 files changed, 61 insertions(+), 53 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 40c2427..612adc5 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -29,7 +29,6 @@ struct cgroup_subsys; struct inode; struct cgroup; struct css_id; -struct eventfd_ctx; extern int cgroup_init_early(void); extern int cgroup_init(void); @@ -239,10 +238,6 @@ struct cgroup { struct rcu_head rcu_head; struct work_struct destroy_work; - /* List of events which userspace want to receive */ - struct list_head event_list; - spinlock_t event_list_lock; - /* directory xattrs */ struct simple_xattrs xattrs; }; @@ -506,25 +501,6 @@ struct cftype { int (*trigger)(struct cgroup_subsys_state *css, unsigned int event); int (*release)(struct inode *inode, struct file *file); - - /* - * register_event() callback will be used to add new userspace - * waiter for changes related to the cftype. Implement it if - * you want to provide this functionality. Use eventfd_signal() - * 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); - /* - * unregister_event() callback will be called when userspace - * closes the eventfd or on cgroup removing. - * This callback must be implemented, if you want provide - * notification functionality. - */ - void (*unregister_event)(struct cgroup_subsys_state *css, - struct cftype *cft, - struct eventfd_ctx *eventfd); }; /* diff --git a/include/linux/vmpressure.h b/include/linux/vmpressure.h index 3f3788d..9dd1914 100644 --- a/include/linux/vmpressure.h +++ b/include/linux/vmpressure.h @@ -7,6 +7,7 @@ #include #include #include +#include struct vmpressure { unsigned long scanned; diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 4bccaa7..feda7c5 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -1352,8 +1352,6 @@ static void init_cgroup_housekeeping(struct cgroup *cgrp) INIT_LIST_HEAD(&cgrp->pidlists); mutex_init(&cgrp->pidlist_mutex); cgrp->dummy_css.cgroup = cgrp; - INIT_LIST_HEAD(&cgrp->event_list); - spin_lock_init(&cgrp->event_list_lock); simple_xattrs_init(&cgrp->xattrs); } diff --git a/mm/memcontrol.c b/mm/memcontrol.c index d003681..2fcacb1 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -249,6 +249,22 @@ struct cgroup_event { */ struct list_head list; /* + * register_event() callback will be used to add new userspace + * waiter for changes related to this event. Use eventfd_signal() + * 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); + /* + * 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 * userspace closes eventfd. */ @@ -362,6 +378,10 @@ struct mem_cgroup { atomic_t numainfo_updating; #endif + /* List of events which userspace want to receive */ + struct list_head event_list; + spinlock_t event_list_lock; + struct mem_cgroup_per_node *nodeinfo[0]; /* WARNING: nodeinfo must be the last member here */ }; @@ -5992,7 +6012,7 @@ static void cgroup_event_remove(struct work_struct *work) remove_wait_queue(event->wqh, &event->wait); - event->cft->unregister_event(css, event->cft, event->eventfd); + event->unregister_event(css, event->cft, event->eventfd); /* Notify userspace the event is going away. */ eventfd_signal(event->eventfd, 1); @@ -6012,7 +6032,7 @@ static int cgroup_event_wake(wait_queue_t *wait, unsigned mode, { struct cgroup_event *event = container_of(wait, struct cgroup_event, wait); - struct cgroup *cgrp = event->css->cgroup; + struct mem_cgroup *memcg = mem_cgroup_from_css(event->css); unsigned long flags = (unsigned long)key; if (flags & POLLHUP) { @@ -6025,7 +6045,7 @@ static int cgroup_event_wake(wait_queue_t *wait, unsigned mode, * side will require wqh->lock via remove_wait_queue(), * which we hold. */ - spin_lock(&cgrp->event_list_lock); + spin_lock(&memcg->event_list_lock); if (!list_empty(&event->list)) { list_del_init(&event->list); /* @@ -6034,7 +6054,7 @@ static int cgroup_event_wake(wait_queue_t *wait, unsigned mode, */ schedule_work(&event->remove); } - spin_unlock(&cgrp->event_list_lock); + spin_unlock(&memcg->event_list_lock); } return 0; @@ -6059,12 +6079,13 @@ static void cgroup_event_ptable_queue_proc(struct file *file, static int cgroup_write_event_control(struct cgroup_subsys_state *css, struct cftype *cft, const char *buffer) { - struct cgroup *cgrp = css->cgroup; + struct mem_cgroup *memcg = mem_cgroup_from_css(css); struct cgroup_event *event; struct cgroup_subsys_state *cfile_css; unsigned int efd, cfd; struct fd efile; struct fd cfile; + const char *name; char *endp; int ret; @@ -6119,6 +6140,31 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css, } /* + * Determine the event callbacks and set them in @event. This used + * to be done via struct cftype but cgroup core no longer knows + * about these events. The following is crude but the whole thing + * is for compatibility anyway. + */ + name = cfile.file->f_dentry->d_name.name; + + if (!strcmp(name, "memory.usage_in_bytes")) { + event->register_event = mem_cgroup_usage_register_event; + event->unregister_event = mem_cgroup_usage_unregister_event; + } else if (!strcmp(name, "memory.oom_control")) { + event->register_event = mem_cgroup_oom_register_event; + event->unregister_event = mem_cgroup_oom_unregister_event; + } else if (!strcmp(name, "memory.pressure_level")) { + 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; + } else { + ret = -EINVAL; + goto out_put_cfile; + } + + /* * Verify @cfile should belong to @css. Also, remaining events are * automatically removed on cgroup destruction but the removal is * asynchronous, so take an extra ref on @css. @@ -6135,21 +6181,15 @@ static int cgroup_write_event_control(struct cgroup_subsys_state *css, if (ret) goto out_put_cfile; - if (!event->cft->register_event || !event->cft->unregister_event) { - ret = -EINVAL; - goto out_put_css; - } - - ret = event->cft->register_event(css, event->cft, - event->eventfd, buffer); + ret = event->register_event(css, event->cft, event->eventfd, buffer); if (ret) goto out_put_css; efile.file->f_op->poll(efile.file, &event->pt); - spin_lock(&cgrp->event_list_lock); - list_add(&event->list, &cgrp->event_list); - spin_unlock(&cgrp->event_list_lock); + spin_lock(&memcg->event_list_lock); + list_add(&event->list, &memcg->event_list); + spin_unlock(&memcg->event_list_lock); fdput(cfile); fdput(efile); @@ -6175,8 +6215,6 @@ static struct cftype mem_cgroup_files[] = { .name = "usage_in_bytes", .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), .read = mem_cgroup_read, - .register_event = mem_cgroup_usage_register_event, - .unregister_event = mem_cgroup_usage_unregister_event, }, { .name = "max_usage_in_bytes", @@ -6236,14 +6274,10 @@ static struct cftype mem_cgroup_files[] = { .name = "oom_control", .read_map = mem_cgroup_oom_control_read, .write_u64 = mem_cgroup_oom_control_write, - .register_event = mem_cgroup_oom_register_event, - .unregister_event = mem_cgroup_oom_unregister_event, .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL), }, { .name = "pressure_level", - .register_event = vmpressure_register_event, - .unregister_event = vmpressure_unregister_event, }, #ifdef CONFIG_NUMA { @@ -6291,8 +6325,6 @@ static struct cftype memsw_cgroup_files[] = { .name = "memsw.usage_in_bytes", .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), .read = mem_cgroup_read, - .register_event = mem_cgroup_usage_register_event, - .unregister_event = mem_cgroup_usage_unregister_event, }, { .name = "memsw.max_usage_in_bytes", @@ -6483,6 +6515,8 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) mutex_init(&memcg->thresholds_lock); spin_lock_init(&memcg->move_lock); vmpressure_init(&memcg->vmpressure); + INIT_LIST_HEAD(&memcg->event_list); + spin_lock_init(&memcg->event_list_lock); return &memcg->css; @@ -6555,7 +6589,6 @@ static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup *memcg) static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) { struct mem_cgroup *memcg = mem_cgroup_from_css(css); - struct cgroup *cgrp = css->cgroup; struct cgroup_event *event, *tmp; /* @@ -6563,12 +6596,12 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css) * Notify userspace about cgroup removing only after rmdir of cgroup * directory to avoid race between userspace and kernelspace. */ - spin_lock(&cgrp->event_list_lock); - list_for_each_entry_safe(event, tmp, &cgrp->event_list, list) { + spin_lock(&memcg->event_list_lock); + list_for_each_entry_safe(event, tmp, &memcg->event_list, list) { list_del_init(&event->list); schedule_work(&event->remove); } - spin_unlock(&cgrp->event_list_lock); + spin_unlock(&memcg->event_list_lock); kmem_cgroup_css_offline(memcg); -- 2.7.4