+ jbd2ext4-dynamically-allocate-the-jbd2-journal-shrinker.patch added to mm-unstable branch

+ jbd2ext4-dynamically-allocate-the-jbd2-journal-shrinker.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: jbd2,ext4: dynamically allocate the jbd2-journal shrinker
has been added to the -mm mm-unstable branch.  Its filename is
     jbd2ext4-dynamically-allocate-the-jbd2-journal-shrinker.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/jbd2ext4-dynamically-allocate-the-jbd2-journal-shrinker.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***

The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days

------------------------------------------------------
From: Qi Zheng <zhengqi.arch@bytedance.com>
Subject: jbd2,ext4: dynamically allocate the jbd2-journal shrinker
Date: Mon, 11 Sep 2023 17:44:30 +0800

In preparation for implementing lockless slab shrink, use new APIs to
dynamically allocate the jbd2-journal 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 journal_s.

Link: https://lkml.kernel.org/r/20230911094444.68966-32-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Jan Kara <jack@suse.cz>
Cc: "Theodore Ts'o" <tytso@mit.edu>
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 Dilger <adilger.kernel@dilger.ca>
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: 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>
---

 fs/jbd2/journal.c    |   29 ++++++++++++++++++-----------
 include/linux/jbd2.h |    2 +-
 2 files changed, 19 insertions(+), 12 deletions(-)

--- a/fs/jbd2/journal.c~jbd2ext4-dynamically-allocate-the-jbd2-journal-shrinker
+++ a/fs/jbd2/journal.c
@@ -1290,7 +1290,7 @@ static int jbd2_min_tag_size(void)
 static unsigned long jbd2_journal_shrink_scan(struct shrinker *shrink,
 					      struct shrink_control *sc)
 {
-	journal_t *journal = container_of(shrink, journal_t, j_shrinker);
+	journal_t *journal = shrink->private_data;
 	unsigned long nr_to_scan = sc->nr_to_scan;
 	unsigned long nr_shrunk;
 	unsigned long count;
@@ -1316,7 +1316,7 @@ static unsigned long jbd2_journal_shrink
 static unsigned long jbd2_journal_shrink_count(struct shrinker *shrink,
 					       struct shrink_control *sc)
 {
-	journal_t *journal = container_of(shrink, journal_t, j_shrinker);
+	journal_t *journal = shrink->private_data;
 	unsigned long count;
 
 	count = percpu_counter_read_positive(&journal->j_checkpoint_jh_count);
@@ -1588,14 +1588,21 @@ static journal_t *journal_init_common(st
 		goto err_cleanup;
 
 	journal->j_shrink_transaction = NULL;
-	journal->j_shrinker.scan_objects = jbd2_journal_shrink_scan;
-	journal->j_shrinker.count_objects = jbd2_journal_shrink_count;
-	journal->j_shrinker.seeks = DEFAULT_SEEKS;
-	journal->j_shrinker.batch = journal->j_max_transaction_buffers;
-	err = register_shrinker(&journal->j_shrinker, "jbd2-journal:(%u:%u)",
-				MAJOR(bdev->bd_dev), MINOR(bdev->bd_dev));
-	if (err)
+
+	journal->j_shrinker = shrinker_alloc(0, "jbd2-journal:(%u:%u)",
+					     MAJOR(bdev->bd_dev),
+					     MINOR(bdev->bd_dev));
+	if (!journal->j_shrinker) {
+		err = -ENOMEM;
 		goto err_cleanup;
+	}
+
+	journal->j_shrinker->scan_objects = jbd2_journal_shrink_scan;
+	journal->j_shrinker->count_objects = jbd2_journal_shrink_count;
+	journal->j_shrinker->batch = journal->j_max_transaction_buffers;
+	journal->j_shrinker->private_data = journal;
+
+	shrinker_register(journal->j_shrinker);
 
 	return journal;
 
@@ -2170,9 +2177,9 @@ int jbd2_journal_destroy(journal_t *jour
 		brelse(journal->j_sb_buffer);
 	}
 
-	if (journal->j_shrinker.flags & SHRINKER_REGISTERED) {
+	if (journal->j_shrinker) {
 		percpu_counter_destroy(&journal->j_checkpoint_jh_count);
-		unregister_shrinker(&journal->j_shrinker);
+		shrinker_free(journal->j_shrinker);
 	}
 	if (journal->j_proc_entry)
 		jbd2_stats_proc_exit(journal);
--- a/include/linux/jbd2.h~jbd2ext4-dynamically-allocate-the-jbd2-journal-shrinker
+++ a/include/linux/jbd2.h
@@ -886,7 +886,7 @@ struct journal_s
 	 * Journal head shrinker, reclaim buffer's journal head which
 	 * has been written back.
 	 */
-	struct shrinker		j_shrinker;
+	struct shrinker		*j_shrinker;
 
 	/**
 	 * @j_checkpoint_jh_count:
_

Patches currently in -mm which might be from zhengqi.arch@bytedance.com are

mm-move-some-shrinker-related-function-declarations-to-mm-internalh.patch
mm-vmscan-move-shrinker-related-code-into-a-separate-file.patch
mm-shrinker-remove-redundant-shrinker_rwsem-in-debugfs-operations.patch
drm-ttm-introduce-pool_shrink_rwsem.patch
mm-shrinker-add-infrastructure-for-dynamically-allocating-shrinker.patch
kvm-mmu-dynamically-allocate-the-x86-mmu-shrinker.patch
binder-dynamically-allocate-the-android-binder-shrinker.patch
drm-ttm-dynamically-allocate-the-drm-ttm_pool-shrinker.patch
xenbus-backend-dynamically-allocate-the-xen-backend-shrinker.patch
erofs-dynamically-allocate-the-erofs-shrinker.patch
f2fs-dynamically-allocate-the-f2fs-shrinker.patch
gfs2-dynamically-allocate-the-gfs2-glock-shrinker.patch
gfs2-dynamically-allocate-the-gfs2-qd-shrinker.patch
nfsv42-dynamically-allocate-the-nfs-xattr-shrinkers.patch
nfs-dynamically-allocate-the-nfs-acl-shrinker.patch
nfsd-dynamically-allocate-the-nfsd-filecache-shrinker.patch
quota-dynamically-allocate-the-dquota-cache-shrinker.patch
ubifs-dynamically-allocate-the-ubifs-slab-shrinker.patch
rcu-dynamically-allocate-the-rcu-lazy-shrinker.patch
rcu-dynamically-allocate-the-rcu-kfree-shrinker.patch
mm-thp-dynamically-allocate-the-thp-related-shrinkers.patch
sunrpc-dynamically-allocate-the-sunrpc_cred-shrinker.patch
mm-workingset-dynamically-allocate-the-mm-shadow-shrinker.patch
drm-i915-dynamically-allocate-the-i915_gem_mm-shrinker.patch
drm-msm-dynamically-allocate-the-drm-msm_gem-shrinker.patch
drm-panfrost-dynamically-allocate-the-drm-panfrost-shrinker.patch
dm-dynamically-allocate-the-dm-bufio-shrinker.patch
dm-zoned-dynamically-allocate-the-dm-zoned-meta-shrinker.patch
md-raid5-dynamically-allocate-the-md-raid5-shrinker.patch
bcache-dynamically-allocate-the-md-bcache-shrinker.patch
vmw_balloon-dynamically-allocate-the-vmw-balloon-shrinker.patch
virtio_balloon-dynamically-allocate-the-virtio-balloon-shrinker.patch
mbcache-dynamically-allocate-the-mbcache-shrinker.patch
ext4-dynamically-allocate-the-ext4-es-shrinker.patch
jbd2ext4-dynamically-allocate-the-jbd2-journal-shrinker.patch
nfsd-dynamically-allocate-the-nfsd-client-shrinker.patch
nfsd-dynamically-allocate-the-nfsd-reply-shrinker.patch
xfs-dynamically-allocate-the-xfs-buf-shrinker.patch
xfs-dynamically-allocate-the-xfs-inodegc-shrinker.patch
xfs-dynamically-allocate-the-xfs-qm-shrinker.patch
zsmalloc-dynamically-allocate-the-mm-zspool-shrinker.patch
fs-super-dynamically-allocate-the-s_shrink.patch
mm-shrinker-remove-old-apis.patch
mm-shrinker-add-a-secondary-array-for-shrinker_info-map-nr_deferred.patch
mm-shrinker-rename-preallocunregister_memcg_shrinker-to-shrinker_memcg_allocremove.patch
mm-shrinker-make-global-slab-shrink-lockless.patch
mm-shrinker-make-memcg-slab-shrink-lockless.patch
mm-shrinker-hold-write-lock-to-reparent-shrinker-nr_deferred.patch
mm-shrinker-convert-shrinker_rwsem-to-mutex.patch