On Thu 05-07-12 02:44:57, Johannes Weiner wrote:
> Only anon pages that are uncharged at the time of the last page table
> mapping vanishing may be in swapcache.
>
> When shmem pages, file pages, swap-freed anon pages, or just migrated
> pages are uncharged, they are known for sure to be not in swapcache.
>
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxx>
> ---
> mm/memcontrol.c | 13 ++++---------
> 1 files changed, 4 insertions(+), 9 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index a3bf414..3d56b4e 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -3026,8 +3026,6 @@ void mem_cgroup_uncharge_cache_page(struct page *page)
> {
> VM_BUG_ON(page_mapped(page));
> VM_BUG_ON(page->mapping);
> - if (PageSwapCache(page))
> - return;
> __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false);
> }
>
> @@ -3092,8 +3090,6 @@ mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
> if (!swapout) /* this was a swap cache but the swap is unused ! */
> ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
>
> - if (PageSwapCache(page))
> - return;
> memcg = __mem_cgroup_uncharge_common(page, ctype, false);
>
> /*
> @@ -3283,11 +3279,10 @@ void mem_cgroup_end_migration(struct mem_cgroup *memcg,
> unused = oldpage;
> }
> anon = PageAnon(used);
> - if (!PageSwapCache(page))
> - __mem_cgroup_uncharge_common(unused,
> - anon ? MEM_CGROUP_CHARGE_TYPE_ANON
> - : MEM_CGROUP_CHARGE_TYPE_CACHE,
> - true);
> + __mem_cgroup_uncharge_common(unused,
> + anon ? MEM_CGROUP_CHARGE_TYPE_ANON
> + : MEM_CGROUP_CHARGE_TYPE_CACHE,
> + true);
> css_put(&memcg->css);
> /*
> * We disallowed uncharge of pages under migration because mapcount
> --
> 1.7.7.6
>
--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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