The patch titled
Subject: mm: memcontrol: catch root bypass in move precharge
has been added to the -mm tree. Its filename is
mm-memcontrol-catch-root-bypass-in-move-precharge.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-catch-root-bypass-in-move-precharge.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-catch-root-bypass-in-move-precharge.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 ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: mm: memcontrol: catch root bypass in move precharge
When mem_cgroup_try_charge() returns -EINTR, it bypassed the charge to the
root memcg. But move precharging does not catch this and treats this case
as if no charge had happened, thus leaking a charge against root. Because
of an old optimization, the root memcg's res_counter is not actually
charged right now, but it's still an imbalance and subsequent patches will
charge the root memcg again.
Catch those bypasses to the root memcg and properly cancel them before
giving up the move.
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff -puN mm/memcontrol.c~mm-memcontrol-catch-root-bypass-in-move-precharge mm/memcontrol.c
--- a/mm/memcontrol.c~mm-memcontrol-catch-root-bypass-in-move-precharge
+++ a/mm/memcontrol.c
@@ -6426,6 +6426,10 @@ static int mem_cgroup_do_precharge(unsig
mc.precharge += count;
return ret;
}
+ if (ret == -EINTR) {
+ __mem_cgroup_cancel_charge(root_mem_cgroup, count);
+ return ret;
+ }
/* Try charges one by one with reclaim */
while (count--) {
@@ -6434,8 +6438,11 @@ static int mem_cgroup_do_precharge(unsig
/*
* In case of failure, any residual charges against
* mc.to will be dropped by mem_cgroup_clear_mc()
- * later on.
+ * later on. However, cancel any charges that are
+ * bypassed to root right away or they'll be lost.
*/
+ if (ret == -EINTR)
+ __mem_cgroup_cancel_charge(root_mem_cgroup, 1);
if (ret)
return ret;
mc.precharge++;
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
vmalloc-use-rcu-list-iterator-to-reduce-vmap_area_lock-contention.patch
memcg-cleanup-memcg_cache_params-refcnt-usage.patch
memcg-destroy-kmem-caches-when-last-slab-is-freed.patch
memcg-mark-caches-that-belong-to-offline-memcgs-as-dead.patch
slub-dont-fail-kmem_cache_shrink-if-slab-placement-optimization-fails.patch
slub-make-slab_free-non-preemptable.patch
memcg-wait-for-kfrees-to-finish-before-destroying-cache.patch
slub-make-dead-memcg-caches-discard-free-slabs-immediately.patch
slab-do-not-keep-free-objects-slabs-on-dead-memcg-caches.patch
mm-memcontrol-fold-mem_cgroup_do_charge.patch
mm-memcontrol-rearrange-charging-fast-path.patch
mm-memcontrol-reclaim-at-least-once-for-__gfp_noretry.patch
mm-huge_memory-use-gfp_transhuge-when-charging-huge-pages.patch
mm-memcontrol-retry-reclaim-for-oom-disabled-and-__gfp_nofail-charges.patch
mm-memcontrol-remove-explicit-oom-parameter-in-charge-path.patch
mm-memcontrol-simplify-move-precharge-function.patch
mm-memcontrol-catch-root-bypass-in-move-precharge.patch
mm-memcontrol-use-root_mem_cgroup-res_counter.patch
mm-memcontrol-remove-ordering-between-pc-mem_cgroup-and-pagecgroupused.patch
mm-memcontrol-do-not-acquire-page_cgroup-lock-for-kmem-pages.patch
mm-memcontrol-rewrite-charge-api.patch
mm-memcontrol-rewrite-uncharge-api.patch
memcg-deprecate-memoryforce_empty-knob.patch
memcg-deprecate-memoryforce_empty-knob-fix.patch
debugging-keep-track-of-page-owners.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
