Re: [PATCH 01/18] mm: fix NUMA node file count error in replace_page_cache()

Alex Shi
2020-04-21T08:29:33Z

在 2020/4/21 上午6:11, Johannes Weiner 写道:
> When replacing one page with another one in the cache, we have to
> decrease the file count of the old page's NUMA node and increase the
> one of the new NUMA node, otherwise the old node leaks the count and
> the new node eventually underflows its counter.
>
> Fixes: 74d609585d8b ("page cache: Add and replace pages using the XArray")
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>

Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>

> ---
> mm/filemap.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 23a051a7ef0f..49e3b5da0216 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -808,11 +808,11 @@ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask)
> old->mapping = NULL;
> /* hugetlb pages do not participate in page cache accounting. */
> if (!PageHuge(old))
> - __dec_node_page_state(new, NR_FILE_PAGES);
> + __dec_node_page_state(old, NR_FILE_PAGES);
> if (!PageHuge(new))
> __inc_node_page_state(new, NR_FILE_PAGES);
> if (PageSwapBacked(old))
> - __dec_node_page_state(new, NR_SHMEM);
> + __dec_node_page_state(old, NR_SHMEM);
> if (PageSwapBacked(new))
> __inc_node_page_state(new, NR_SHMEM);
> xas_unlock_irqrestore(&xas, flags);
>