The patch titled
Subject: memcg: fix split_huge_page_refcounts()
has been added to the -mm tree. Its filename is
memcg-fix-split_huge_page_refcounts.patch
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------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: memcg: fix split_huge_page_refcounts()
This patch started off as a cleanup: __split_huge_page_refcounts() has to
cope with two scenarios, when the hugepage being split is already on LRU,
and when it is not; but why does it have to split that accounting across
three different sites? Consolidate it in lru_add_page_tail(), handling
evictable and unevictable alike, and use standard add_page_to_lru_list()
when accounting is needed (when the head is not yet on LRU).
But a recent regression in -next, I guess the removal of PageCgroupAcctLRU
test from mem_cgroup_split_huge_fixup(), makes this now a necessary fix:
under load, the MEM_CGROUP_ZSTAT count was wrapping to a huge number,
messing up reclaim calculations and causing a freeze at rmdir of cgroup.
Add a VM_BUG_ON to mem_cgroup_lru_del_list() when we're about to wrap that
count - this has not been the only such incident. Document that
lru_add_page_tail() is for Transparent HugePages by #ifdef around it.
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 10 ----------
mm/memcontrol.c | 12 ++----------
mm/swap.c | 29 +++++++++++++++++++----------
3 files changed, 21 insertions(+), 30 deletions(-)
diff -puN mm/huge_memory.c~memcg-fix-split_huge_page_refcounts mm/huge_memory.c
--- a/mm/huge_memory.c~memcg-fix-split_huge_page_refcounts
+++ a/mm/huge_memory.c
@@ -1229,7 +1229,6 @@ static void __split_huge_page_refcount(s
{
int i;
struct zone *zone = page_zone(page);
- int zonestat;
int tail_count = 0;
/* prevent PageLRU to go away from under us, and freeze lru stats */
@@ -1317,15 +1316,6 @@ static void __split_huge_page_refcount(s
__dec_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES);
__mod_zone_page_state(zone, NR_ANON_PAGES, HPAGE_PMD_NR);
- /*
- * A hugepage counts for HPAGE_PMD_NR pages on the LRU statistics,
- * so adjust those appropriately if this page is on the LRU.
- */
- if (PageLRU(page)) {
- zonestat = NR_LRU_BASE + page_lru(page);
- __mod_zone_page_state(zone, zonestat, -(HPAGE_PMD_NR-1));
- }
-
ClearPageCompound(page);
compound_unlock(page);
spin_unlock_irq(&zone->lru_lock);
diff -puN mm/memcontrol.c~memcg-fix-split_huge_page_refcounts mm/memcontrol.c
--- a/mm/memcontrol.c~memcg-fix-split_huge_page_refcounts
+++ a/mm/memcontrol.c
@@ -1062,6 +1062,7 @@ void mem_cgroup_lru_del_list(struct page
VM_BUG_ON(!memcg);
mz = page_cgroup_zoneinfo(memcg, page);
/* huge page split is done under lru_lock. so, we have no races. */
+ VM_BUG_ON(MEM_CGROUP_ZSTAT(mz, lru) < (1 << compound_order(page)));
MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page);
}
@@ -2456,9 +2457,7 @@ static void __mem_cgroup_commit_charge(s
void mem_cgroup_split_huge_fixup(struct page *head)
{
struct page_cgroup *head_pc = lookup_page_cgroup(head);
- struct mem_cgroup_per_zone *mz;
struct page_cgroup *pc;
- enum lru_list lru;
int i;
if (mem_cgroup_disabled())
@@ -2469,15 +2468,8 @@ void mem_cgroup_split_huge_fixup(struct
smp_wmb();/* see __commit_charge() */
pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
}
- /*
- * Tail pages will be added to LRU.
- * We hold lru_lock,then,reduce counter directly.
- */
- lru = page_lru(head);
- mz = page_cgroup_zoneinfo(head_pc->mem_cgroup, head);
- MEM_CGROUP_ZSTAT(mz, lru) -= HPAGE_PMD_NR - 1;
}
-#endif
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
/**
* mem_cgroup_move_account - move account of the page
diff -puN mm/swap.c~memcg-fix-split_huge_page_refcounts mm/swap.c
--- a/mm/swap.c~memcg-fix-split_huge_page_refcounts
+++ a/mm/swap.c
@@ -717,6 +717,7 @@ void __pagevec_release(struct pagevec *p
EXPORT_SYMBOL(__pagevec_release);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/* used by __split_huge_page_refcount() */
void lru_add_page_tail(struct zone* zone,
struct page *page, struct page *page_tail)
@@ -733,8 +734,6 @@ void lru_add_page_tail(struct zone* zone
SetPageLRU(page_tail);
if (page_evictable(page_tail, NULL)) {
- struct lruvec *lruvec;
-
if (PageActive(page)) {
SetPageActive(page_tail);
active = 1;
@@ -744,18 +743,28 @@ void lru_add_page_tail(struct zone* zone
lru = LRU_INACTIVE_ANON;
}
update_page_reclaim_stat(zone, page_tail, file, active);
- lruvec = mem_cgroup_lru_add_list(zone, page_tail, lru);
- if (likely(PageLRU(page)))
- list_add(&page_tail->lru, page->lru.prev);
- else
- list_add(&page_tail->lru, lruvec->lists[lru].prev);
- __mod_zone_page_state(zone, NR_LRU_BASE + lru,
- hpage_nr_pages(page_tail));
} else {
SetPageUnevictable(page_tail);
- add_page_to_lru_list(zone, page_tail, LRU_UNEVICTABLE);
+ lru = LRU_UNEVICTABLE;
+ }
+
+ if (likely(PageLRU(page)))
+ list_add_tail(&page_tail->lru, &page->lru);
+ else {
+ struct list_head *list_head;
+ /*
+ * Head page has not yet been counted, as an hpage,
+ * so we must account for each subpage individually.
+ *
+ * Use the standard add function to put page_tail on the list,
+ * but then correct its position so they all end up in order.
+ */
+ add_page_to_lru_list(zone, page_tail, lru);
+ list_head = page_tail->lru.prev;
+ list_move_tail(&page_tail->lru, list_head);
}
}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
static void ____pagevec_lru_add_fn(struct page *page, void *arg)
{
_
Subject: Subject: memcg: fix split_huge_page_refcounts()
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
linux-next.patch
mm-add-free_hot_cold_page_list-helper.patch
mm-add-free_hot_cold_page_list-helper-v2.patch
mm-add-free_hot_cold_page_list-helper-v3.patch
mm-remove-unused-pagevec_free.patch
mm-tracepoint-rename-page-free-events.patch
mm-tracepoint-fixup-documentation-and-examples.patch
mremap-enforce-rmap-src-dst-vma-ordering-in-case-of-vma_merge-succeeding-in-copy_vma.patch
mremap-enforce-rmap-src-dst-vma-ordering-in-case-of-vma_merge-succeeding-in-copy_vma-update.patch
mm-simplify-find_vma_prev.patch
memcg-add-mem_cgroup_replace_page_cache-to-fix-lru-issue.patch
mm-memcg-consolidate-hierarchy-iteration-primitives.patch
mm-vmscan-distinguish-global-reclaim-from-global-lru-scanning.patch
mm-vmscan-distinguish-between-memcg-triggering-reclaim-and-memcg-being-scanned.patch
mm-memcg-per-priority-per-zone-hierarchy-scan-generations.patch
mm-move-memcg-hierarchy-reclaim-to-generic-reclaim-code.patch
mm-memcg-remove-optimization-of-keeping-the-root_mem_cgroup-lru-lists-empty.patch
mm-vmscan-convert-global-reclaim-to-per-memcg-lru-lists.patch
mm-collect-lru-list-heads-into-struct-lruvec.patch
mm-make-per-memcg-lru-lists-exclusive.patch
mm-memcg-remove-unused-node-section-info-from-pc-flags.patch
mm-memcg-remove-unused-node-section-info-from-pc-flags-fix.patch
mm-oom_kill-remove-memcg-argument-from-oom_kill_task.patch
mm-unify-remaining-mem_cont-mem-etc-variable-names-to-memcg.patch
mm-memcg-clean-up-fault-accounting.patch
mm-memcg-lookup_page_cgroup-almost-never-returns-null.patch
mm-memcg-lookup_page_cgroup-almost-never-returns-null-fix.patch
mm-page_cgroup-check-page_cgroup-arrays-in-lookup_page_cgroup-only-when-necessary.patch
mm-memcg-remove-unneeded-checks-from-newpage_charge.patch
mm-memcg-remove-unneeded-checks-from-uncharge_page.patch
memcg-clean-up-soft_limit_tree-if-allocation-fails.patch
memcg-simplify-page-cache-charging.patch
memcg-simplify-corner-case-handling-of-lru.patch
memcg-clear-pc-mem_cgorup-if-necessary.patch
memcg-clear-pc-mem_cgorup-if-necessary-fix.patch
memcg-clear-pc-mem_cgorup-if-necessary-fix-2.patch
memcg-clear-pc-mem_cgorup-if-necessary-fix-2-fix.patch
memcg-clear-pc-mem_cgorup-if-necessary-fix-3.patch
memcg-clear-pc-mem_cgorup-if-necessary-fix-page-migration-to-reset_owner.patch
memcg-simplify-lru-handling-by-new-rule.patch
memcg-simplify-lru-handling-by-new-rule-fix.patch
memcg-simplify-lru-handling-by-new-rule-memcg-return-eintr-at-bypassing-try_charge.patch
memcg-simplify-lru-handling-by-new-rule-memcg-return-eintr-at-bypassing-try_charge-fix.patch
memcg-simplify-lru-handling-by-new-rule-memcg-return-eintr-at-bypassing-try_charge-fix-null-mem_cgroup_try_charge.patch
memcg-fix-split_huge_page_refcounts.patch
memcg-fix-mem_cgroup_print_bad_page.patch
procfs-add-hidepid=-and-gid=-mount-options-fix.patch
radix_tree-remove-radix_tree_indirect_to_ptr.patch
radix_tree-take-radix_tree_path-off-stack.patch
radix_tree-take-radix_tree_path-off-stack-expand-comment-on-optimization.patch
prio_tree-debugging-patch.patch
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