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