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Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Meta kernel team , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: khugepaged: fix NR_FILE_PAGES accounting in collapse_file() Message-ID: References: <20260129184054.910897-1-shakeel.butt@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260129184054.910897-1-shakeel.butt@linux.dev> X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 6C941A000A X-Stat-Signature: hg5dqjrw6ziwuaejo9qzxgmu13hkkjic X-Rspam-User: X-HE-Tag: 1769726851-812840 X-HE-Meta: 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 NI88ZnI2 sOQnCwD8lc2b5EB4ljBi+prkDEbsvesN8UBB3Ua6e610K1R7XwyI8t8LWXYs3xulKbOmNkQDEW34a0kpYRiDyL63gi1MeWNRxrtw+4dsKSJL9TSVlFd1A8SSEYLKWjJw0oKVGKI2rpmD5b+h81n2U8h/ka4uADb6dr5WQWNRBvqdBTu+1YCcdQDpp3SSiTNSrrfXJzsClNCJVZLbM8Gp5GEJUHAQf+iMCzhYFzw32BJCHmJvVhMx4dYALvXnRtGXM5q3ZCGhTzE5DgXDtbfjh67rQYEckpLtkKfmiVS1XnIJdGujNbrty85lJVqfKRdNw5/OB7Z1l9Jbm32s= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Jan 29, 2026 at 10:40:54AM -0800, Shakeel Butt wrote: > Fixes: 99cb0dbd47a1 ("mm,thp: add read-only THP support for (non-shmem) FS") Are you sure this is the right Fixes? 99cb0dbd47a1 wasn't cgroup aware: if (nr_none) { struct zone *zone = page_zone(new_page); __mod_node_page_state(zone->zone_pgdat, NR_FILE_PAGES, nr_none); - __mod_node_page_state(zone->zone_pgdat, NR_SHMEM, nr_none); + if (is_shmem) + __mod_node_page_state(zone->zone_pgdat, + NR_SHMEM, nr_none); } b8eddff8886b added cgroup support: if (is_shmem) - __inc_node_page_state(new_page, NR_SHMEM_THPS); + __inc_lruvec_page_state(new_page, NR_SHMEM_THPS); else { - __inc_node_page_state(new_page, NR_FILE_THPS); + __inc_lruvec_page_state(new_page, NR_FILE_THPS); filemap_nr_thps_inc(mapping); } which would seem like the right Fixes: to me? > Signed-off-by: Shakeel Butt > --- > mm/khugepaged.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 1d994b6c58c6..1cf8e154e214 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -2200,8 +2200,8 @@ static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr, > else > lruvec_stat_mod_folio(new_folio, NR_FILE_THPS, HPAGE_PMD_NR); > > + lruvec_stat_mod_folio(new_folio, NR_FILE_PAGES, HPAGE_PMD_NR); > if (nr_none) { > - lruvec_stat_mod_folio(new_folio, NR_FILE_PAGES, nr_none); > /* nr_none is always 0 for non-shmem. */ > lruvec_stat_mod_folio(new_folio, NR_SHMEM, nr_none); > } > @@ -2238,6 +2238,8 @@ static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr, > */ > list_for_each_entry_safe(folio, tmp, &pagelist, lru) { > list_del(&folio->lru); > + lruvec_stat_mod_folio(folio, NR_FILE_PAGES, > + -folio_nr_pages(folio)); > folio->mapping = NULL; > folio_clear_active(folio); > folio_clear_unevictable(folio); > -- > 2.47.3 > >