[PATCH 11/29] virtio_balloon: dynamically allocate the virtio-balloon shrinker
From: Qi Zheng <hidden>
Date: 2023-06-22 08:58:51
Also in:
dm-devel, dri-devel, intel-gfx, linux-arm-msm, linux-bcache, linux-btrfs, linux-ext4, linux-fsdevel, linux-mm, linux-nfs, linux-xfs, lkml
Subsystem:
the rest, virtio balloon, virtio core · Maintainers:
Linus Torvalds, "Michael S. Tsirkin", David Hildenbrand, Jason Wang
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 <redacted> --- 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)
--
2.30.2