The patch titled mm: remove cgroup_mm_owner_callbacks has been added to the -mm tree. Its filename is mm-remove-cgroup_mm_owner_callbacks.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: mm: remove cgroup_mm_owner_callbacks From: Hugh Dickins <hugh@xxxxxxxxxxx> cgroup_mm_owner_callbacks() was brought in to support the memrlimit controller, but sneaked into mainline ahead of it. That controller has now been shelved, and the mm_owner_changed() args were inadequate for it anyway (they needed an mm pointer instead of a task pointer). Remove the dead code, and restore mm_update_next_owner() locking to how it was before: taking mmap_sem there does nothing for memcontrol.c, now the only user of mm->owner. Signed-off-by: Hugh Dickins <hugh@xxxxxxxxxxx> Cc: Paul Menage <menage@xxxxxxxxxx> Cc: Balbir Singh <balbir@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/cgroup.h | 14 +------------- kernel/cgroup.c | 33 --------------------------------- kernel/exit.c | 16 ++++++---------- 3 files changed, 7 insertions(+), 56 deletions(-) diff -puN include/linux/cgroup.h~mm-remove-cgroup_mm_owner_callbacks include/linux/cgroup.h --- a/include/linux/cgroup.h~mm-remove-cgroup_mm_owner_callbacks +++ a/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 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(stru 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 -puN kernel/cgroup.c~mm-remove-cgroup_mm_owner_callbacks kernel/cgroup.c --- a/kernel/cgroup.c~mm-remove-cgroup_mm_owner_callbacks +++ a/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(st 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_s } } -#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 -puN kernel/exit.c~mm-remove-cgroup_mm_owner_callbacks kernel/exit.c --- a/kernel/exit.c~mm-remove-cgroup_mm_owner_callbacks +++ a/kernel/exit.c @@ -638,35 +638,31 @@ 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 */ _ Patches currently in -mm which might be from hugh@xxxxxxxxxxx are origin.patch linux-next.patch mm-dont-mark_page_accessed-in-shmem_fault.patch mm-apply_to_range-call-pte-function-with-lazy-updates.patch mm-remove-cgroup_mm_owner_callbacks.patch mm-remove-aop_writepage_activate.patch mm-remove-gfp_highuser_pagecache.patch mm-add-setclearpageswapcache-stubs.patch mm-replace-some-bug_ons-by-vm_bug_ons.patch mm-add_active_or_unevictable-into-rmap.patch mm-make-page_lock_anon_vma-static.patch memcg-handle-swap-caches.patch memcg-handle-swap-caches-build-fix.patch memcg-swap-cgroup-for-remembering-usage-fix-2.patch memcg-swap-cgroup-for-remembering-usage-fix-3.patch memcg-swap-cgroup-for-remembering-usage-fix-4.patch memcg-memswap-controller-core.patch memcg-memswap-controller-core-make-resize-limit-hold-mutex.patch prio_tree-debugging-patch.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html