[PATCH v4 34/48] jbd2,ext4: dynamically allocate the jbd2-journal shrinker
From: Qi Zheng <hidden>
Date: 2023-08-07 11:20:17
Also in:
dm-devel, dri-devel, kvm, linux-arm-msm, linux-bcache, linux-btrfs, linux-f2fs-devel, linux-fsdevel, linux-mm, linux-nfs, linux-raid, linux-xfs, lkml, netdev, rcu, xen-devel
Subsystem:
filesystems (vfs and infrastructure), journalling layer for block devices (jbd2), the rest · Maintainers:
Alexander Viro, Christian Brauner, "Theodore Ts'o", Jan Kara, Linus Torvalds
In preparation for implementing lockless slab shrink, use new APIs to dynamically allocate the jbd2-journal shrinker, so that it can be freed asynchronously using kfree_rcu(). Then it doesn't need to wait for RCU read-side critical section when releasing the struct journal_s. Signed-off-by: Qi Zheng <redacted> Reviewed-by: Muchun Song <redacted> --- fs/jbd2/journal.c | 27 +++++++++++++++++---------- include/linux/jbd2.h | 2 +- 2 files changed, 18 insertions(+), 11 deletions(-)
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 1b5a45ab62b0..4c421da03fee 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c@@ -1298,7 +1298,7 @@ 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;
@@ -1324,7 +1324,7 @@ static unsigned long jbd2_journal_shrink_scan(struct shrinker *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);
@@ -1412,19 +1412,26 @@ static journal_t *journal_init_common(struct block_device *bdev, journal->j_superblock = (journal_superblock_t *)bh->b_data; 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; if (percpu_counter_init(&journal->j_checkpoint_jh_count, 0, GFP_KERNEL)) goto err_cleanup; - if (register_shrinker(&journal->j_shrinker, "jbd2-journal:(%u:%u)", - MAJOR(bdev->bd_dev), MINOR(bdev->bd_dev))) { + journal->j_shrinker = shrinker_alloc(0, "jbd2-journal:(%u:%u)", + MAJOR(bdev->bd_dev), + MINOR(bdev->bd_dev)); + if (!journal->j_shrinker) { percpu_counter_destroy(&journal->j_checkpoint_jh_count); goto err_cleanup; } + + 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; + journal->j_shrinker->private_data = journal; + + shrinker_register(journal->j_shrinker); + return journal; err_cleanup:
@@ -2187,9 +2194,9 @@ int jbd2_journal_destroy(journal_t *journal) 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);
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 44c298aa58d4..beb4c4586320 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h@@ -891,7 +891,7 @@ 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:
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2.30.2