linux-kernel - [PATCH] mm: Fix shmem THP counters on migration

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230619055735.141740-1-jglauber@digitalocean.com>
Date:   Mon, 19 Jun 2023 07:57:35 +0200
From:   Jan Glauber <jglauber@...italocean.com>
To:     akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Jan Glauber <jglauber@...italocean.com>
Subject: [PATCH] mm: Fix shmem THP counters on migration

The per node numa_stat values for shmem don't change on
page migration for THP:

  grep shmem /sys/fs/cgroup/machine.slice/.../memory.numa_stat:

    shmem N0=1092616192 N1=10485760
    shmem_thp N0=1092616192 N1=10485760

  migratepages 9181 0 1:

    shmem N0=0 N1=1103101952
    shmem_thp N0=1092616192 N1=10485760

Fix that by updating shmem_thp counters likewise to shmem counters
on page migration.

Signed-off-by: Jan Glauber <jglauber@...italocean.com>
---
 mm/migrate.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/mm/migrate.c b/mm/migrate.c
index 01cac26a3127..d2ba786ea105 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -492,6 +492,11 @@ int folio_migrate_mapping(struct address_space *mapping,
 		if (folio_test_swapbacked(folio) && !folio_test_swapcache(folio)) {
 			__mod_lruvec_state(old_lruvec, NR_SHMEM, -nr);
 			__mod_lruvec_state(new_lruvec, NR_SHMEM, nr);
+
+			if (folio_test_transhuge(folio)) {
+				__mod_lruvec_state(old_lruvec, NR_SHMEM_THP, -nr);
+				__mod_lruvec_state(new_lruvec, NR_SHMEM_THP, nr);
+			}
 		}
 #ifdef CONFIG_SWAP
 		if (folio_test_swapcache(folio)) {
-- 
2.25.1