[Devel] [PATCH] mm: Fix mis accounting of isolated pages in memcg_numa_isolate_pages()

[Andrey Ryabinin]

On 11/13/2017 02:50 PM, Kirill Tkhai wrote:
> When split_huge_page_to_list() fails, and a huge page is going back
> to LRU, the number of isolated pages is decreasing. So we must
> subtract HPAGE_PMD_NR from NR_ISOLATED_ANON counter, not to add it.
> 
> Otherwise, we may bumped into a situation, when number of isolated
> pages grows up to number of inactive pages, and direct reclaim hangs in:
> 
>   shrink_inactive_list()
>      while (too_many_isolated())
>         congestion_wait(BLK_RW_ASYNC, HZ/10),
> 
> waiting for the counter becomes less. But it has no a chance
> to finish, and hangs forever. Fix that.
> 
> https://jira.sw.ru/browse/PSBM-76970
> 
> Signed-off-by: Kirill Tkhai <ktkhai at virtuozzo.com>

Acked-by: Andrey Ryabinin <aryabinin at virtuozzo.com>