From 0fbb99698b165444e3cf5421f96de01d9d56baf4 Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Mon, 11 Sep 2023 17:44:27 +0800 Subject: virtio_balloon: dynamically allocate the virtio-balloon shrinker In preparation for implementing lockless slab shrink, use new APIs to dynamically allocate the virtio-balloon shrinker, so that it can be freed asynchronously via RCU. Then it doesn't need to wait for RCU read-side critical section when releasing the struct virtio_balloon. Link: https://lkml.kernel.org/r/20230911094444.68966-29-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Reviewed-by: Muchun Song Cc: "Michael S. Tsirkin" Cc: David Hildenbrand Cc: Jason Wang Cc: Xuan Zhuo Cc: Abhinav Kumar Cc: Alasdair Kergon Cc: Alexander Viro Cc: Alyssa Rosenzweig Cc: Andreas Dilger Cc: Andreas Gruenbacher Cc: Anna Schumaker Cc: Arnd Bergmann Cc: Bob Peterson Cc: Borislav Petkov Cc: Carlos Llamas Cc: Chandan Babu R Cc: Chao Yu Cc: Chris Mason Cc: Christian Brauner Cc: Christian Koenig Cc: Chuck Lever Cc: Coly Li Cc: Dai Ngo Cc: Daniel Vetter Cc: Daniel Vetter Cc: "Darrick J. Wong" Cc: Dave Chinner Cc: Dave Hansen Cc: David Airlie Cc: David Sterba Cc: Dmitry Baryshkov Cc: Gao Xiang Cc: Greg Kroah-Hartman Cc: Huang Rui Cc: Ingo Molnar Cc: Jaegeuk Kim Cc: Jani Nikula Cc: Jan Kara Cc: Jeff Layton Cc: Jeffle Xu Cc: Joel Fernandes (Google) Cc: Joonas Lahtinen Cc: Josef Bacik Cc: Juergen Gross Cc: Kent Overstreet Cc: Kirill Tkhai Cc: Marijn Suijten Cc: Mike Snitzer Cc: Minchan Kim Cc: Muchun Song Cc: Nadav Amit Cc: Neil Brown Cc: Oleksandr Tyshchenko Cc: Olga Kornievskaia Cc: Paul E. McKenney Cc: Richard Weinberger Cc: Rob Clark Cc: Rob Herring Cc: Rodrigo Vivi Cc: Roman Gushchin Cc: Sean Paul Cc: Sergey Senozhatsky Cc: Song Liu Cc: Stefano Stabellini Cc: Steven Price Cc: "Theodore Ts'o" Cc: Thomas Gleixner Cc: Tomeu Vizoso Cc: Tom Talpey Cc: Trond Myklebust Cc: Tvrtko Ursulin Cc: Vlastimil Babka Cc: Yue Hu Signed-off-by: Andrew Morton --- drivers/virtio/virtio_balloon.c | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) (limited to 'drivers/virtio/virtio_balloon.c') diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c index 5b15936a5214..5cdc7b081baa 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 +845,22 @@ static int virtio_balloon_oom_notify(struct notifier_block *nb, static void virtio_balloon_unregister_shrinker(struct virtio_balloon *vb) { - unregister_shrinker(&vb->shrinker); + shrinker_free(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; + vb->shrinker = shrinker_alloc(0, "virtio-balloon"); + if (!vb->shrinker) + return -ENOMEM; - return register_shrinker(&vb->shrinker, "virtio-balloon"); + vb->shrinker->scan_objects = virtio_balloon_shrinker_scan; + vb->shrinker->count_objects = virtio_balloon_shrinker_count; + vb->shrinker->private_data = vb; + + shrinker_register(vb->shrinker); + + return 0; } static int virtballoon_probe(struct virtio_device *vdev) -- cgit