| Message ID | 20230727080502.77895-28-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 dm-bufio 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 dm_bufio_client. > > Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> > Reviewed-by: Muchun Song <songmuchun@bytedance.com> > --- > drivers/md/dm-bufio.c | 26 +++++++++++++++----------- > 1 file changed, 15 insertions(+), 11 deletions(-) > > diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c > index bc309e41d074..5a9124b83d53 100644 > --- a/drivers/md/dm-bufio.c > +++ b/drivers/md/dm-bufio.c > @@ -963,7 +963,7 @@ struct dm_bufio_client { > > sector_t start; > > - struct shrinker shrinker; > + struct shrinker *shrinker; > struct work_struct shrink_work; > atomic_long_t need_shrink; > > @@ -2368,7 +2368,7 @@ static unsigned long dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink > { > struct dm_bufio_client *c; > > - c = container_of(shrink, struct dm_bufio_client, shrinker); > + c = shrink->private_data; > atomic_long_add(sc->nr_to_scan, &c->need_shrink); > queue_work(dm_bufio_wq, &c->shrink_work); > > @@ -2377,7 +2377,7 @@ static unsigned long dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink > > static unsigned long dm_bufio_shrink_count(struct shrinker *shrink, struct shrink_control *sc) > { > - struct dm_bufio_client *c = container_of(shrink, struct dm_bufio_client, shrinker); > + struct dm_bufio_client *c = shrink->private_data; > unsigned long count = cache_total(&c->cache); > unsigned long retain_target = get_retain_buffers(c); > unsigned long queued_for_cleanup = atomic_long_read(&c->need_shrink); > @@ -2490,15 +2490,19 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign > INIT_WORK(&c->shrink_work, shrink_work); > atomic_long_set(&c->need_shrink, 0); > > - c->shrinker.count_objects = dm_bufio_shrink_count; > - c->shrinker.scan_objects = dm_bufio_shrink_scan; > - c->shrinker.seeks = 1; > - c->shrinker.batch = 0; > - r = register_shrinker(&c->shrinker, "dm-bufio:(%u:%u)", > - MAJOR(bdev->bd_dev), MINOR(bdev->bd_dev)); > - if (r) > + c->shrinker = shrinker_alloc(0, "dm-bufio:(%u:%u)", > + MAJOR(bdev->bd_dev), MINOR(bdev->bd_dev)); > + if (!c->shrinker) Here should set r to -ENOMEM, will fix. > goto bad; > > + c->shrinker->count_objects = dm_bufio_shrink_count; > + c->shrinker->scan_objects = dm_bufio_shrink_scan; > + c->shrinker->seeks = 1; > + c->shrinker->batch = 0; > + c->shrinker->private_data = c; > + > + shrinker_register(c->shrinker); > + > mutex_lock(&dm_bufio_clients_lock); > dm_bufio_client_count++; > list_add(&c->client_list, &dm_bufio_all_clients); > @@ -2537,7 +2541,7 @@ void dm_bufio_client_destroy(struct dm_bufio_client *c) > > drop_buffers(c); > > - unregister_shrinker(&c->shrinker); > + shrinker_free(c->shrinker); > flush_work(&c->shrink_work); > > mutex_lock(&dm_bufio_clients_lock);
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c index bc309e41d074..5a9124b83d53 100644 --- a/drivers/md/dm-bufio.c +++ b/drivers/md/dm-bufio.c @@ -963,7 +963,7 @@ struct dm_bufio_client { sector_t start; - struct shrinker shrinker; + struct shrinker *shrinker; struct work_struct shrink_work; atomic_long_t need_shrink; @@ -2368,7 +2368,7 @@ static unsigned long dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink { struct dm_bufio_client *c; - c = container_of(shrink, struct dm_bufio_client, shrinker); + c = shrink->private_data; atomic_long_add(sc->nr_to_scan, &c->need_shrink); queue_work(dm_bufio_wq, &c->shrink_work); @@ -2377,7 +2377,7 @@ static unsigned long dm_bufio_shrink_scan(struct shrinker *shrink, struct shrink static unsigned long dm_bufio_shrink_count(struct shrinker *shrink, struct shrink_control *sc) { - struct dm_bufio_client *c = container_of(shrink, struct dm_bufio_client, shrinker); + struct dm_bufio_client *c = shrink->private_data; unsigned long count = cache_total(&c->cache); unsigned long retain_target = get_retain_buffers(c); unsigned long queued_for_cleanup = atomic_long_read(&c->need_shrink); @@ -2490,15 +2490,19 @@ struct dm_bufio_client *dm_bufio_client_create(struct block_device *bdev, unsign INIT_WORK(&c->shrink_work, shrink_work); atomic_long_set(&c->need_shrink, 0); - c->shrinker.count_objects = dm_bufio_shrink_count; - c->shrinker.scan_objects = dm_bufio_shrink_scan; - c->shrinker.seeks = 1; - c->shrinker.batch = 0; - r = register_shrinker(&c->shrinker, "dm-bufio:(%u:%u)", - MAJOR(bdev->bd_dev), MINOR(bdev->bd_dev)); - if (r) + c->shrinker = shrinker_alloc(0, "dm-bufio:(%u:%u)", + MAJOR(bdev->bd_dev), MINOR(bdev->bd_dev)); + if (!c->shrinker) goto bad; + c->shrinker->count_objects = dm_bufio_shrink_count; + c->shrinker->scan_objects = dm_bufio_shrink_scan; + c->shrinker->seeks = 1; + c->shrinker->batch = 0; + c->shrinker->private_data = c; + + shrinker_register(c->shrinker); + mutex_lock(&dm_bufio_clients_lock); dm_bufio_client_count++; list_add(&c->client_list, &dm_bufio_all_clients); @@ -2537,7 +2541,7 @@ void dm_bufio_client_destroy(struct dm_bufio_client *c) drop_buffers(c); - unregister_shrinker(&c->shrinker); + shrinker_free(c->shrinker); flush_work(&c->shrink_work); mutex_lock(&dm_bufio_clients_lock);