The quilt patch titled
Subject: mm: shrinker: remove redundant shrinker_rwsem in debugfs operations
has been removed from the -mm tree. Its filename was
mm-shrinker-remove-redundant-shrinker_rwsem-in-debugfs-operations.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Subject: mm: shrinker: remove redundant shrinker_rwsem in debugfs operations
Date: Mon, 11 Sep 2023 17:25:16 +0800
debugfs_remove_recursive() will wait for debugfs_file_put() to return, so
the shrinker will not be freed when doing debugfs operations (such as
shrinker_debugfs_count_show() and shrinker_debugfs_scan_write()), so there
is no need to hold shrinker_rwsem during debugfs operations.
Link: https://lkml.kernel.org/r/20230911092517.64141-4-zhengqi.arch@xxxxxxxxxxxxx
Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Christian Brauner <brauner@xxxxxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
Cc: Chuck Lever <cel@xxxxxxxxxx>
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Darrick J. Wong <djwong@xxxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>
Cc: Kirill Tkhai <tkhai@xxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Cc: Steven Price <steven.price@xxxxxxx>
Cc: Theodore Ts'o <tytso@xxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
Cc: Alasdair Kergon <agk@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@xxxxxxxxxxxxx>
Cc: Andreas Dilger <adilger.kernel@xxxxxxxxx>
Cc: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
Cc: Anna Schumaker <anna@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Bob Peterson <rpeterso@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Carlos Llamas <cmllamas@xxxxxxxxxx>
Cc: Chandan Babu R <chandan.babu@xxxxxxxxxx>
Cc: Chao Yu <chao@xxxxxxxxxx>
Cc: Chris Mason <clm@xxxxxx>
Cc: Coly Li <colyli@xxxxxxx>
Cc: Dai Ngo <Dai.Ngo@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Airlie <airlied@xxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Sterba <dsterba@xxxxxxxx>
Cc: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
Cc: Gao Xiang <hsiangkao@xxxxxxxxxxxxxxxxx>
Cc: Huang Rui <ray.huang@xxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Jason Wang <jasowang@xxxxxxxxxx>
Cc: Jeff Layton <jlayton@xxxxxxxxxx>
Cc: Jeffle Xu <jefflexu@xxxxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Josef Bacik <josef@xxxxxxxxxxxxxx>
Cc: Juergen Gross <jgross@xxxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: Marijn Suijten <marijn.suijten@xxxxxxxxxxxxxx>
Cc: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
Cc: Mike Snitzer <snitzer@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Nadav Amit <namit@xxxxxxxxxx>
Cc: Neil Brown <neilb@xxxxxxx>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
Cc: Olga Kornievskaia <kolga@xxxxxxxxxx>
Cc: Richard Weinberger <richard@xxxxxx>
Cc: Rob Clark <robdclark@xxxxxxxxx>
Cc: Rob Herring <robh@xxxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Cc: Sean Paul <sean@xxxxxxxxxx>
Cc: Song Liu <song@xxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
Cc: Tom Talpey <tom@xxxxxxxxxx>
Cc: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx>
Cc: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
Cc: Yue Hu <huyue2@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/shrinker_debug.c | 16 +---------------
1 file changed, 1 insertion(+), 15 deletions(-)
--- a/mm/shrinker_debug.c~mm-shrinker-remove-redundant-shrinker_rwsem-in-debugfs-operations
+++ a/mm/shrinker_debug.c
@@ -51,17 +51,12 @@ static int shrinker_debugfs_count_show(s
struct mem_cgroup *memcg;
unsigned long total;
bool memcg_aware;
- int ret, nid;
+ int ret = 0, nid;
count_per_node = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
if (!count_per_node)
return -ENOMEM;
- ret = down_read_killable(&shrinker_rwsem);
- if (ret) {
- kfree(count_per_node);
- return ret;
- }
rcu_read_lock();
memcg_aware = shrinker->flags & SHRINKER_MEMCG_AWARE;
@@ -94,7 +89,6 @@ static int shrinker_debugfs_count_show(s
} while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
rcu_read_unlock();
- up_read(&shrinker_rwsem);
kfree(count_per_node);
return ret;
@@ -119,7 +113,6 @@ static ssize_t shrinker_debugfs_scan_wri
struct mem_cgroup *memcg = NULL;
int nid;
char kbuf[72];
- ssize_t ret;
read_len = size < (sizeof(kbuf) - 1) ? size : (sizeof(kbuf) - 1);
if (copy_from_user(kbuf, buf, read_len))
@@ -148,12 +141,6 @@ static ssize_t shrinker_debugfs_scan_wri
return -EINVAL;
}
- ret = down_read_killable(&shrinker_rwsem);
- if (ret) {
- mem_cgroup_put(memcg);
- return ret;
- }
-
sc.nid = nid;
sc.memcg = memcg;
sc.nr_to_scan = nr_to_scan;
@@ -161,7 +148,6 @@ static ssize_t shrinker_debugfs_scan_wri
shrinker->scan_objects(shrinker, &sc);
- up_read(&shrinker_rwsem);
mem_cgroup_put(memcg);
return size;
_
Patches currently in -mm which might be from zhengqi.arch@xxxxxxxxxxxxx are
