From: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> In preparation for implementing lockless slab shrink, we need to dynamically allocate the md-raid5 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 r5conf. Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> --- drivers/md/raid5.c | 28 +++++++++++++++++----------- drivers/md/raid5.h | 2 +- 2 files changed, 18 insertions(+), 12 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index f4eea1bbbeaf..4866cad1ad62 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -7391,7 +7391,7 @@ static void free_conf(struct r5conf *conf) log_exit(conf); - unregister_shrinker(&conf->shrinker); + unregister_and_free_shrinker(conf->shrinker); free_thread_groups(conf); shrink_stripes(conf); raid5_free_percpu(conf); @@ -7439,7 +7439,7 @@ 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)) { @@ -7460,7 +7460,7 @@ 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 */ @@ -7695,16 +7695,21 @@ 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)); + conf->shrinker = shrinker_alloc_and_init(raid5_cache_count, + raid5_cache_scan, 128, + DEFAULT_SEEKS * conf->raid_disks * 4, + 0, conf); + if (!conf->shrinker) { + pr_warn("md/raid:%s: couldn't allocate shrinker.\n", + mdname(mddev)); + goto abort; + } + + ret = register_shrinker(conf->shrinker, "md-raid5:%s", mdname(mddev)); if (ret) { pr_warn("md/raid:%s: couldn't register shrinker.\n", mdname(mddev)); - goto abort; + goto abort_shrinker; } sprintf(pers_name, "raid%d", mddev->new_level); @@ -7717,7 +7722,8 @@ static struct r5conf *setup_conf(struct mddev *mddev) } return conf; - +abort_shrinker: + shrinker_free(conf->shrinker); abort: if (conf) free_conf(conf); diff --git a/drivers/md/raid5.h b/drivers/md/raid5.h index 6a92fafb0748..806f84681599 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