ext4: dynamically allocate the ext4-es shrinker

In preparation for implementing lockless slab shrink, use new APIs to
dynamically allocate the ext4-es shrinker, so that it can be freed
asynchronously via RCU. Then it doesn't need to wait for RCU read-side
critical section when releasing the struct ext4_sb_info.

Link: https://lkml.kernel.org/r/20230911094444.68966-31-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Abhinav Kumar <quic_abhinavk@quicinc.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Anna Schumaker <anna@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Chandan Babu R <chandan.babu@oracle.com>
Cc: Chao Yu <chao@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Chuck Lever <cel@kernel.org>
Cc: Coly Li <colyli@suse.de>
Cc: Dai Ngo <Dai.Ngo@oracle.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc: Gao Xiang <hsiangkao@linux.alibaba.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Huang Rui <ray.huang@amd.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Jeffle Xu <jefflexu@linux.alibaba.com>
Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Kirill Tkhai <tkhai@ya.ru>
Cc: Marijn Suijten <marijn.suijten@somainline.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nadav Amit <namit@vmware.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Olga Kornievskaia <kolga@netapp.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rob Clark <robdclark@gmail.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Sean Paul <sean@poorly.run>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Song Liu <song@kernel.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: Yue Hu <huyue2@coolpad.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 9418359b1d9d3b0fb8f57d26f3dfdfb3970fb4ba..8eeff770992cebb304c86ba2875986fd8bbdbefd 100644 (file)
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1653,7 +1653,7 @@ struct ext4_sb_info {
        __u32 s_csum_seed;
 
        /* Reclaim extents from extent status tree */
-       struct shrinker s_es_shrinker;
+       struct shrinker *s_es_shrinker;
        struct list_head s_es_list;     /* List of inodes with reclaimable extents */
        long s_es_nr_inode;
        struct ext4_es_stats s_es_stats;

diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c
index 6f7de14c0fa86f00906f2ce01fbc4905d22fc2c6..deec7d1f4e50deff50fde3a2456f05f9b5c03130 100644 (file)
--- a/fs/ext4/extents_status.c
+++ b/fs/ext4/extents_status.c
@@ -1606,7 +1606,7 @@ static unsigned long ext4_es_count(struct shrinker *shrink,
        unsigned long nr;
        struct ext4_sb_info *sbi;
 
-       sbi = container_of(shrink, struct ext4_sb_info, s_es_shrinker);
+       sbi = shrink->private_data;
        nr = percpu_counter_read_positive(&sbi->s_es_stats.es_stats_shk_cnt);
        trace_ext4_es_shrink_count(sbi->s_sb, sc->nr_to_scan, nr);
        return nr;
@@ -1615,8 +1615,7 @@ static unsigned long ext4_es_count(struct shrinker *shrink,
 static unsigned long ext4_es_scan(struct shrinker *shrink,
                                  struct shrink_control *sc)
 {
-       struct ext4_sb_info *sbi = container_of(shrink,
-                                       struct ext4_sb_info, s_es_shrinker);
+       struct ext4_sb_info *sbi = shrink->private_data;
        int nr_to_scan = sc->nr_to_scan;
        int ret, nr_shrunk;
 
@@ -1700,13 +1699,17 @@ int ext4_es_register_shrinker(struct ext4_sb_info *sbi)
        if (err)
                goto err3;
 
-       sbi->s_es_shrinker.scan_objects = ext4_es_scan;
-       sbi->s_es_shrinker.count_objects = ext4_es_count;
-       sbi->s_es_shrinker.seeks = DEFAULT_SEEKS;
-       err = register_shrinker(&sbi->s_es_shrinker, "ext4-es:%s",
-                               sbi->s_sb->s_id);
-       if (err)
+       sbi->s_es_shrinker = shrinker_alloc(0, "ext4-es:%s", sbi->s_sb->s_id);
+       if (!sbi->s_es_shrinker) {
+               err = -ENOMEM;
                goto err4;
+       }
+
+       sbi->s_es_shrinker->scan_objects = ext4_es_scan;
+       sbi->s_es_shrinker->count_objects = ext4_es_count;
+       sbi->s_es_shrinker->private_data = sbi;
+
+       shrinker_register(sbi->s_es_shrinker);
 
        return 0;
 err4:
@@ -1726,7 +1729,7 @@ void ext4_es_unregister_shrinker(struct ext4_sb_info *sbi)
        percpu_counter_destroy(&sbi->s_es_stats.es_stats_cache_misses);
        percpu_counter_destroy(&sbi->s_es_stats.es_stats_all_cnt);
        percpu_counter_destroy(&sbi->s_es_stats.es_stats_shk_cnt);
-       unregister_shrinker(&sbi->s_es_shrinker);
+       shrinker_free(sbi->s_es_shrinker);
 }
 
 /*