The patch titled
Subject: mm: memcg: only check anon swapin page charges for swap cache
has been removed from the -mm tree. Its filename was
mm-memcg-only-check-anon-swapin-page-charges-for-swap-cache.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: mm: memcg: only check anon swapin page charges for swap cache
shmem knows for sure that the page is in swap cache when attempting to
charge a page, because the cache charge entry function has a check for it.
Only anon pages may be removed from swap cache already when trying to
charge their swapin.
Adjust the comment, though: '4969c11 mm: fix swapin race condition' added
a stable PageSwapCache check under the page lock in the do_swap_page()
before calling the memory controller, so it's unuse_pte()'s pte_same()
that may fail.
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Wanpeng Li <liwp.linux@xxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
diff -puN mm/memcontrol.c~mm-memcg-only-check-anon-swapin-page-charges-for-swap-cache mm/memcontrol.c
--- a/mm/memcontrol.c~mm-memcg-only-check-anon-swapin-page-charges-for-swap-cache
+++ a/mm/memcontrol.c
@@ -2818,14 +2818,6 @@ static int __mem_cgroup_try_charge_swapi
return 0;
if (!do_swap_account)
goto charge_cur_mm;
- /*
- * A racing thread's fault, or swapoff, may have already updated
- * the pte, and even removed page from swap cache: in those cases
- * do_swap_page()'s pte_same() test will fail; but there's also a
- * KSM case which does need to charge the page.
- */
- if (!PageSwapCache(page))
- goto charge_cur_mm;
memcg = try_get_mem_cgroup_from_page(page);
if (!memcg)
goto charge_cur_mm;
@@ -2848,6 +2840,20 @@ int mem_cgroup_try_charge_swapin(struct
*memcgp = NULL;
if (mem_cgroup_disabled())
return 0;
+ /*
+ * A racing thread's fault, or swapoff, may have already
+ * updated the pte, and even removed page from swap cache: in
+ * those cases unuse_pte()'s pte_same() test will fail; but
+ * there's also a KSM case which does need to charge the page.
+ */
+ if (!PageSwapCache(page)) {
+ int ret;
+
+ ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, memcgp, true);
+ if (ret == -EINTR)
+ ret = 0;
+ return ret;
+ }
return __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, memcgp);
}
_
Patches currently in -mm which might be from hannes@xxxxxxxxxxx are
origin.patch
mm-slab-remove-duplicate-check.patch
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