| Message ID | 20230727080502.77895-30-zhengqi.arch@bytedance.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | use refcount+RCU method to implement lockless slab shrink | expand |
On 2023/7/27 16:04, Qi Zheng wrote: > In preparation for implementing lockless slab shrink, use new APIs 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@bytedance.com> > Reviewed-by: Muchun Song <songmuchun@bytedance.com> > --- > drivers/md/raid5.c | 25 ++++++++++++++----------- > drivers/md/raid5.h | 2 +- > 2 files changed, 15 insertions(+), 12 deletions(-) > > diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c > index 85b3004594e0..fbb4e6f5ff43 100644 > --- a/drivers/md/raid5.c > +++ b/drivers/md/raid5.c > @@ -7414,7 +7414,7 @@ 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); > @@ -7462,7 +7462,7 @@ 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)) { > @@ -7483,7 +7483,7 @@ 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 */ > @@ -7718,18 +7718,21 @@ 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)); > - 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) { Here should set ret to -ENOMEM, will fix. > + 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;
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 85b3004594e0..fbb4e6f5ff43 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -7414,7 +7414,7 @@ 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); @@ -7462,7 +7462,7 @@ 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)) { @@ -7483,7 +7483,7 @@ 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 */ @@ -7718,18 +7718,21 @@ 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)); - 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) { + 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;