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From: Qi Zheng To: akpm@linux-foundation.org, david@fromorbit.com, tkhai@ya.ru, vbabka@suse.cz, roman.gushchin@linux.dev, djwong@kernel.org, brauner@kernel.org, paulmck@kernel.org, tytso@mit.edu Date: Thu, 22 Jun 2023 08:39:14 +0000 Message-Id: <20230622083932.4090339-12-qi.zheng@linux.dev> In-Reply-To: <20230622083932.4090339-1-qi.zheng@linux.dev> References: <20230622083932.4090339-1-qi.zheng@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 X-Mailman-Approved-At: Fri, 23 Jun 2023 05:25:40 +0000 Subject: [dm-devel] [PATCH 11/29] virtio_balloon: dynamically allocate the virtio-balloon shrinker X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-bcache@vger.kernel.org, linux-xfs@vger.kernel.org, linux-nfs@vger.kernel.org, linux-arm-msm@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, virtualization@lists.linux-foundation.org, linux-raid@vger.kernel.org, linux-mm@kvack.org, dm-devel@redhat.com, Qi Zheng , linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, freedreno@lists.freedesktop.org, linux-btrfs@vger.kernel.org Errors-To: dm-devel-bounces@redhat.com Sender: "dm-devel" X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: linux.dev From: Qi Zheng In preparation for implementing lockless slab shrink, we need to dynamically allocate the virtio-balloon 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 virtio_balloon. Signed-off-by: Qi Zheng --- drivers/virtio/virtio_balloon.c | 26 ++++++++++++++++---------- 1 file changed, 16 insertions(+), 10 deletions(-) diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 5b15936a5214..fa051bff8d90 100644 --- a/drivers/virtio/virtio_balloon.c +++ b/drivers/virtio/virtio_balloon.c @@ -111,7 +111,7 @@ struct virtio_balloon { struct virtio_balloon_stat stats[VIRTIO_BALLOON_S_NR]; /* Shrinker to return free pages - VIRTIO_BALLOON_F_FREE_PAGE_HINT */ - struct shrinker shrinker; + struct shrinker *shrinker; /* OOM notifier to deflate on OOM - VIRTIO_BALLOON_F_DEFLATE_ON_OOM */ struct notifier_block oom_nb; @@ -816,8 +816,7 @@ static unsigned long shrink_free_pages(struct virtio_balloon *vb, static unsigned long virtio_balloon_shrinker_scan(struct shrinker *shrinker, struct shrink_control *sc) { - struct virtio_balloon *vb = container_of(shrinker, - struct virtio_balloon, shrinker); + struct virtio_balloon *vb = shrinker->private_data; return shrink_free_pages(vb, sc->nr_to_scan); } @@ -825,8 +824,7 @@ static unsigned long virtio_balloon_shrinker_scan(struct shrinker *shrinker, static unsigned long virtio_balloon_shrinker_count(struct shrinker *shrinker, struct shrink_control *sc) { - struct virtio_balloon *vb = container_of(shrinker, - struct virtio_balloon, shrinker); + struct virtio_balloon *vb = shrinker->private_data; return vb->num_free_page_blocks * VIRTIO_BALLOON_HINT_BLOCK_PAGES; } @@ -847,16 +845,24 @@ static int virtio_balloon_oom_notify(struct notifier_block *nb, static void virtio_balloon_unregister_shrinker(struct virtio_balloon *vb) { - unregister_shrinker(&vb->shrinker); + unregister_and_free_shrinker(vb->shrinker); } static int virtio_balloon_register_shrinker(struct virtio_balloon *vb) { - vb->shrinker.scan_objects = virtio_balloon_shrinker_scan; - vb->shrinker.count_objects = virtio_balloon_shrinker_count; - vb->shrinker.seeks = DEFAULT_SEEKS; + int ret; + + vb->shrinker = shrinker_alloc_and_init(virtio_balloon_shrinker_count, + virtio_balloon_shrinker_scan, + 0, DEFAULT_SEEKS, 0, vb); + if (!vb->shrinker) + return -ENOMEM; + + ret = register_shrinker(vb->shrinker, "virtio-balloon"); + if (ret) + shrinker_free(vb->shrinker); - return register_shrinker(&vb->shrinker, "virtio-balloon"); + return ret; } static int virtballoon_probe(struct virtio_device *vdev)