Messages in this thread | | | Date | Thu, 27 Jul 2023 17:15:44 +0800 | Subject | Re: [PATCH v3 29/49] md/raid5: dynamically allocate the md-raid5 shrinker | From | Qi Zheng <> |
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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;
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