The patch titled
Subject: mm: memcontrol: shorten the page statistics update slowpath
has been added to the -mm tree. Its filename is
mm-memcontrol-shorten-the-page-statistics-update-slowpath.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memcontrol-shorten-the-page-statistics-update-slowpath.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memcontrol-shorten-the-page-statistics-update-slowpath.patch
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------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: mm: memcontrol: shorten the page statistics update slowpath
While moving charges from one memcg to another, page stat updates must
acquire the old memcg's move_lock to prevent double accounting. That
situation is denoted by an increased memcg->move_accounting. However, the
charge moving code declares this way too early for now, even before
summing up the RSS and pre-allocating destination charges.
Shorten this slowpath mode by increasing memcg->move_accounting only right
before walking the task's address space with the intention of actually
moving the pages.
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Reviewed-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 21 ++++++++-------------
1 file changed, 8 insertions(+), 13 deletions(-)
diff -puN mm/memcontrol.c~mm-memcontrol-shorten-the-page-statistics-update-slowpath mm/memcontrol.c
--- a/mm/memcontrol.c~mm-memcontrol-shorten-the-page-statistics-update-slowpath
+++ a/mm/memcontrol.c
@@ -5246,8 +5246,6 @@ static void __mem_cgroup_clear_mc(void)
static void mem_cgroup_clear_mc(void)
{
- struct mem_cgroup *from = mc.from;
-
/*
* we must clear moving_task before waking up waiters at the end of
* task migration.
@@ -5258,8 +5256,6 @@ static void mem_cgroup_clear_mc(void)
mc.from = NULL;
mc.to = NULL;
spin_unlock(&mc.lock);
-
- atomic_dec(&from->moving_account);
}
static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
@@ -5293,15 +5289,6 @@ static int mem_cgroup_can_attach(struct
VM_BUG_ON(mc.moved_charge);
VM_BUG_ON(mc.moved_swap);
- /*
- * Signal mem_cgroup_begin_page_stat() to take
- * the memcg's move_lock while we're moving
- * its pages to another memcg. Then wait for
- * already started RCU-only updates to finish.
- */
- atomic_inc(&from->moving_account);
- synchronize_rcu();
-
spin_lock(&mc.lock);
mc.from = from;
mc.to = memcg;
@@ -5433,6 +5420,13 @@ static void mem_cgroup_move_charge(struc
struct vm_area_struct *vma;
lru_add_drain_all();
+ /*
+ * Signal mem_cgroup_begin_page_stat() to take the memcg's
+ * move_lock while we're moving its pages to another memcg.
+ * Then wait for already started RCU-only updates to finish.
+ */
+ atomic_inc(&mc.from->moving_account);
+ synchronize_rcu();
retry:
if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
/*
@@ -5465,6 +5459,7 @@ retry:
break;
}
up_read(&mm->mmap_sem);
+ atomic_dec(&mc.from->moving_account);
}
static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
cgroup-kmemleak-add-kmemleak_free-for-cgroup-deallocations.patch
mm-page-writeback-inline-account_page_dirtied-into-single-caller.patch
mm-memcontrol-fix-missed-end-writeback-page-accounting.patch
mm-memcontrol-fix-missed-end-writeback-page-accounting-fix.patch
mm-rmap-split-out-page_remove_file_rmap.patch
slab-print-slabinfo-header-in-seq-show.patch
mm-memcontrol-lockless-page-counters.patch
mm-memcontrol-lockless-page-counters-fix.patch
mm-memcontrol-lockless-page-counters-fix-fix.patch
mm-memcontrol-lockless-page-counters-fix-2.patch
mm-hugetlb_cgroup-convert-to-lockless-page-counters.patch
kernel-res_counter-remove-the-unused-api.patch
kernel-res_counter-remove-the-unused-api-fix.patch
kernel-res_counter-remove-the-unused-api-fix-2.patch
mm-memcontrol-convert-reclaim-iterator-to-simple-css-refcounting.patch
mm-memcontrol-convert-reclaim-iterator-to-simple-css-refcounting-fix.patch
mm-memcontrol-take-a-css-reference-for-each-charged-page.patch
mm-memcontrol-remove-obsolete-kmemcg-pinning-tricks.patch
mm-memcontrol-continue-cache-reclaim-from-offlined-groups.patch
mm-memcontrol-remove-synchroneous-stock-draining-code.patch
mm-vmscan-count-only-dirty-pages-as-congested.patch
memcg-simplify-unreclaimable-groups-handling-in-soft-limit-reclaim.patch
mm-memcontrol-update-mem_cgroup_page_lruvec-documentation.patch
mm-memcontrol-clarify-migration-where-old-page-is-uncharged.patch
memcg-remove-activate_kmem_mutex.patch
mm-memcontrol-micro-optimize-mem_cgroup_split_huge_fixup.patch
mm-memcontrol-uncharge-pages-on-swapout.patch
mm-memcontrol-uncharge-pages-on-swapout-fix.patch
mm-memcontrol-remove-unnecessary-pcg_memsw-memoryswap-charge-flag.patch
mm-memcontrol-remove-unnecessary-pcg_mem-memory-charge-flag.patch
mm-memcontrol-remove-unnecessary-pcg_used-pc-mem_cgroup-valid-flag.patch
mm-memcontrol-remove-unnecessary-pcg_used-pc-mem_cgroup-valid-flag-fix.patch
mm-memcontrol-inline-memcg-move_lock-locking.patch
mm-memcontrol-dont-pass-a-null-memcg-to-mem_cgroup_end_move.patch
mm-memcontrol-fold-mem_cgroup_start_move-mem_cgroup_end_move.patch
mm-memcontrol-fold-mem_cgroup_start_move-mem_cgroup_end_move-fix.patch
memcg-remove-mem_cgroup_reclaimable-check-from-soft-reclaim.patch
mm-memcontrol-do-not-filter-reclaimable-nodes-in-numa-round-robin.patch
memcg-use-generic-slab-iterators-for-showing-slabinfo.patch
mm-memcontrol-shorten-the-page-statistics-update-slowpath.patch
debugging-keep-track-of-page-owners.patch
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