From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Shi Subject: Re: [PATCH 01/18] mm: fix NUMA node file count error in replace_page_cache() Date: Tue, 21 Apr 2020 16:28:10 +0800 Message-ID: References: <20200420221126.341272-1-hannes@cmpxchg.org> <20200420221126.341272-2-hannes@cmpxchg.org> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20200420221126.341272-2-hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="iso-8859-1" To: Johannes Weiner , Joonsoo Kim Cc: Shakeel Butt , Hugh Dickins , Michal Hocko , "Kirill A. Shutemov" , Roman Gushchin , linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kernel-team-b10kYP2dOMg@public.gmane.org =D4=DA 2020/4/21 =C9=CF=CE=E76:11, Johannes Weiner =D0=B4=B5=C0: > 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. >=20 > Fixes: 74d609585d8b ("page cache: Add and replace pages using the XArray") > Signed-off-by: Johannes Weiner Reviewed-by: Alex Shi > --- > mm/filemap.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) >=20 > 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, struc= t page *new, gfp_t gfp_mask) > old->mapping =3D 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); >=20