The patch titled
mm: remove cgroup_mm_owner_callbacks
has been removed from the -mm tree. Its filename was
mm-remove-cgroup_mm_owner_callbacks.patch
This patch was dropped because it was merged into mainline or a subsystem tree
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
@@ -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 */
_
Patches currently in -mm which might be from hugh@xxxxxxxxxxx are
origin.patch
linux-next.patch
mark-complex-bitopsh-inlines-as-__always_inline.patch
clocksource-pass-clocksource-to-read-callback.patch
clocksource-pass-clocksource-to-read-callback-sparc-cleanup.patch
bio-zero-inlined-bio_vec.patch
page_fault-retry-with-nopage_retry.patch
page_fault-retry-with-nopage_retry-fix.patch
page_fault-retry-with-nopage_retry-fix-fix.patch
mm-shmemc-fix-division-by-zero.patch
getrusage-fill-ru_maxrss-value.patch
memcg-handle-swap-caches.patch
memcg-handle-swap-caches-build-fix.patch
memcg-swap-cgroup-for-remembering-usage.patch
memcg-memswap-controller-core.patch
memcg-memswap-controller-core-make-resize-limit-hold-mutex.patch
memcg-memswap-controller-core-swapcache-fixes.patch
memcg-revert-gfp-mask-fix.patch
memcg-check-group-leader-fix.patch
memcg-memoryswap-controller-fix-limit-check.patch
memcg-swapout-refcnt-fix.patch
memcg-hierarchy-avoid-unnecessary-reclaim.patch
inactive_anon_is_low-move-to-vmscan.patch
mm-introduce-zone_reclaim-struct.patch
mm-add-zone-nr_pages-helper-function.patch
mm-make-get_scan_ratio-safe-for-memcg.patch
memcg-add-null-check-to-page_cgroup_zoneinfo.patch
memcg-add-inactive_anon_is_low.patch
memcg-add-mem_cgroup_zone_nr_pages.patch
memcg-add-zone_reclaim_stat.patch
memcg-add-zone_reclaim_stat-reclaim-stat-trivial-fixes-fix.patch
memcg-remove-mem_cgroup_cal_reclaim.patch
memcg-show-reclaim-stat.patch
memcg-rename-scan-global-lru.patch
memcg-protect-prev_priority.patch
memcg-swappiness.patch
memcg-explain-details-and-test-document.patch
memcg-fix-swap-accounting-leak-v3.patch
memcg-fix-swap-accounting-leak-doc-fix.patch
memcg-fix-shmems-swap-accounting.patch
prio_tree-debugging-patch.patch
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