[PATCH v5 25/45] md/raid5: dynamically allocate the md-raid5 shrinker
From: Qi Zheng <hidden>
Date: 2023-08-24 03:50:15
In preparation for implementing lockless slab shrink, use new APIs to dynamically allocate the md-raid5 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 r5conf. Signed-off-by: Qi Zheng <redacted> Reviewed-by: Muchun Song <redacted> CC: Song Liu <song@kernel.org> CC: linux-raid@vger.kernel.org --- drivers/md/raid5.c | 26 +++++++++++++++----------- drivers/md/raid5.h | 2 +- 2 files changed, 16 insertions(+), 12 deletions(-)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 4cb9c608ee19..c8d2c6e50aa1 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c@@ -7401,7 +7401,7 @@ static void free_conf(struct r5conf *conf) log_exit(conf); - unregister_shrinker(&conf->shrinker); + shrinker_free(conf->shrinker); free_thread_groups(conf); shrink_stripes(conf); raid5_free_percpu(conf);
@@ -7449,7 +7449,7 @@ static int raid5_alloc_percpu(struct r5conf *conf) static unsigned long raid5_cache_scan(struct shrinker *shrink, struct shrink_control *sc) { - struct r5conf *conf = container_of(shrink, struct r5conf, shrinker); + struct r5conf *conf = shrink->private_data; unsigned long ret = SHRINK_STOP; if (mutex_trylock(&conf->cache_size_mutex)) {
@@ -7470,7 +7470,7 @@ static unsigned long raid5_cache_scan(struct shrinker *shrink, static unsigned long raid5_cache_count(struct shrinker *shrink, struct shrink_control *sc) { - struct r5conf *conf = container_of(shrink, struct r5conf, shrinker); + struct r5conf *conf = shrink->private_data; if (conf->max_nr_stripes < conf->min_nr_stripes) /* unlikely, but not impossible */
@@ -7705,18 +7705,22 @@ static struct r5conf *setup_conf(struct mddev *mddev) * it reduces the queue depth and so can hurt throughput. * So set it rather large, scaled by number of devices. */ - conf->shrinker.seeks = DEFAULT_SEEKS * conf->raid_disks * 4; - conf->shrinker.scan_objects = raid5_cache_scan; - conf->shrinker.count_objects = raid5_cache_count; - conf->shrinker.batch = 128; - conf->shrinker.flags = 0; - ret = register_shrinker(&conf->shrinker, "md-raid5:%s", mdname(mddev)); - if (ret) { - pr_warn("md/raid:%s: couldn't register shrinker.\n", + conf->shrinker = shrinker_alloc(0, "md-raid5:%s", mdname(mddev)); + if (!conf->shrinker) { + ret = -ENOMEM; + pr_warn("md/raid:%s: couldn't allocate shrinker.\n", mdname(mddev)); goto abort; } + conf->shrinker->seeks = DEFAULT_SEEKS * conf->raid_disks * 4; + conf->shrinker->scan_objects = raid5_cache_scan; + conf->shrinker->count_objects = raid5_cache_count; + conf->shrinker->batch = 128; + conf->shrinker->private_data = conf; + + shrinker_register(conf->shrinker); + sprintf(pers_name, "raid%d", mddev->new_level); rcu_assign_pointer(conf->thread, md_register_thread(raid5d, mddev, pers_name));
diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h
index 97a795979a35..22bea20eccbd 100644
--- a/drivers/md/raid5.h
+++ b/drivers/md/raid5.h@@ -670,7 +670,7 @@ struct r5conf { wait_queue_head_t wait_for_stripe; wait_queue_head_t wait_for_overlap; unsigned long cache_state; - struct shrinker shrinker; + struct shrinker *shrinker; int pool_size; /* number of disks in stripeheads in pool */ spinlock_t device_lock; struct disk_info *disks;
--
2.30.2