diff options
| -rw-r--r-- | include/linux/cgroup.h | 14 | ||||
| -rw-r--r-- | kernel/cgroup.c | 33 | ||||
| -rw-r--r-- | kernel/exit.c | 16 |
3 files changed, 7 insertions, 56 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 1164963c3a8..08b78c09b09 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -329,13 +329,7 @@ struct cgroup_subsys { struct cgroup *cgrp); void (*post_clone)(struct cgroup_subsys *ss, struct cgroup *cgrp); void (*bind)(struct cgroup_subsys *ss, struct cgroup *root); - /* - * This routine is called with the task_lock of mm->owner held - */ - void (*mm_owner_changed)(struct cgroup_subsys *ss, - struct cgroup *old, - struct cgroup *new, - struct task_struct *p); + int subsys_id; int active; int disabled; @@ -400,9 +394,6 @@ void cgroup_iter_end(struct cgroup *cgrp, struct cgroup_iter *it); int cgroup_scan_tasks(struct cgroup_scanner *scan); int cgroup_attach_task(struct cgroup *, struct task_struct *); -void cgroup_mm_owner_callbacks(struct task_struct *old, - struct task_struct *new); - #else /* !CONFIG_CGROUPS */ static inline int cgroup_init_early(void) { return 0; } @@ -420,9 +411,6 @@ static inline int cgroupstats_build(struct cgroupstats *stats, return -EINVAL; } -static inline void cgroup_mm_owner_callbacks(struct task_struct *old, - struct task_struct *new) {} - #endif /* !CONFIG_CGROUPS */ #endif /* _LINUX_CGROUP_H */ diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 87bb0258fd2..f221446aa02 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -116,7 +116,6 @@ static int root_count; * be called. */ static int need_forkexit_callback __read_mostly; -static int need_mm_owner_callback __read_mostly; /* convenient tests for these bits */ inline int cgroup_is_removed(const struct cgroup *cgrp) @@ -2539,7 +2538,6 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) init_css_set.subsys[ss->subsys_id] = dummytop->subsys[ss->subsys_id]; need_forkexit_callback |= ss->fork || ss->exit; - need_mm_owner_callback |= !!ss->mm_owner_changed; /* At system boot, before all subsystems have been * registered, no tasks have been forked, so we don't @@ -2789,37 +2787,6 @@ void cgroup_fork_callbacks(struct task_struct *child) } } -#ifdef CONFIG_MM_OWNER -/** - * cgroup_mm_owner_callbacks - run callbacks when the mm->owner changes - * @p: the new owner - * - * Called on every change to mm->owner. mm_init_owner() does not - * invoke this routine, since it assigns the mm->owner the first time - * and does not change it. - * - * The callbacks are invoked with mmap_sem held in read mode. - */ -void cgroup_mm_owner_callbacks(struct task_struct *old, struct task_struct *new) -{ - struct cgroup *oldcgrp, *newcgrp = NULL; - - if (need_mm_owner_callback) { - int i; - for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { - struct cgroup_subsys *ss = subsys[i]; - oldcgrp = task_cgroup(old, ss->subsys_id); - if (new) - newcgrp = task_cgroup(new, ss->subsys_id); - if (oldcgrp == newcgrp) - continue; - if (ss->mm_owner_changed) - ss->mm_owner_changed(ss, oldcgrp, newcgrp, new); - } - } -} -#endif /* CONFIG_MM_OWNER */ - /** * cgroup_post_fork - called on a new task after adding it to the task list * @child: the task in question diff --git a/kernel/exit.c b/kernel/exit.c index c9e5a1c14e0..f923724ab3c 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -642,35 +642,31 @@ retry: /* * We found no owner yet mm_users > 1: this implies that we are * most likely racing with swapoff (try_to_unuse()) or /proc or - * ptrace or page migration (get_task_mm()). Mark owner as NULL, - * so that subsystems can understand the callback and take action. + * ptrace or page migration (get_task_mm()). Mark owner as NULL. */ - down_write(&mm->mmap_sem); - cgroup_mm_owner_callbacks(mm->owner, NULL); mm->owner = NULL; - up_write(&mm->mmap_sem); return; assign_new_owner: BUG_ON(c == p); get_task_struct(c); - read_unlock(&tasklist_lock); - down_write(&mm->mmap_sem); /* * The task_lock protects c->mm from changing. * We always want mm->owner->mm == mm */ task_lock(c); + /* + * Delay read_unlock() till we have the task_lock() + * to ensure that c does not slip away underneath us + */ + read_unlock(&tasklist_lock); if (c->mm != mm) { task_unlock(c); - up_write(&mm->mmap_sem); put_task_struct(c); goto retry; } - cgroup_mm_owner_callbacks(mm->owner, c); mm->owner = c; task_unlock(c); - up_write(&mm->mmap_sem); put_task_struct(c); } #endif /* CONFIG_MM_OWNER */ |