[PATCH 16/29] NFSD: dynamically allocate the nfsd-reply shrinker
From: Qi Zheng <hidden>
Date: 2023-06-22 09:01:25
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:
filesystems (vfs and infrastructure), kernel nfsd, sunrpc, and lockd servers, the rest · Maintainers:
Alexander Viro, Christian Brauner, Chuck Lever, Jeff Layton, Linus Torvalds
In preparation for implementing lockless slab shrink, we need to dynamically allocate the nfsd-reply 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 nfsd_net. Signed-off-by: Qi Zheng <redacted> --- fs/nfsd/netns.h | 2 +- fs/nfsd/nfscache.c | 33 +++++++++++++++++++-------------- 2 files changed, 20 insertions(+), 15 deletions(-)
diff --git a/fs/nfsd/netns.h b/fs/nfsd/netns.h
index f669444d5336..ab303a8b77d5 100644
--- a/fs/nfsd/netns.h
+++ b/fs/nfsd/netns.h@@ -177,7 +177,7 @@ struct nfsd_net { /* size of cache when we saw the longest hash chain */ unsigned int longest_chain_cachesize; - struct shrinker nfsd_reply_cache_shrinker; + struct shrinker *nfsd_reply_cache_shrinker; /* tracking server-to-server copy mounts */ spinlock_t nfsd_ssc_lock;
diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index 041faa13b852..ec33de8e418b 100644
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c@@ -173,19 +173,23 @@ int nfsd_reply_cache_init(struct nfsd_net *nn) if (status) goto out_nomem; - nn->nfsd_reply_cache_shrinker.scan_objects = nfsd_reply_cache_scan; - nn->nfsd_reply_cache_shrinker.count_objects = nfsd_reply_cache_count; - nn->nfsd_reply_cache_shrinker.seeks = 1; - status = register_shrinker(&nn->nfsd_reply_cache_shrinker, - "nfsd-reply:%s", nn->nfsd_name); - if (status) - goto out_stats_destroy; - nn->drc_hashtbl = kvzalloc(array_size(hashsize, sizeof(*nn->drc_hashtbl)), GFP_KERNEL); if (!nn->drc_hashtbl) + goto out_stats_destroy; + + nn->nfsd_reply_cache_shrinker = + shrinker_alloc_and_init(nfsd_reply_cache_count, + nfsd_reply_cache_scan, + 0, 1, 0, nn); + if (!nn->nfsd_reply_cache_shrinker) goto out_shrinker; + status = register_shrinker(nn->nfsd_reply_cache_shrinker, + "nfsd-reply:%s", nn->nfsd_name); + if (status) + goto out_register; + for (i = 0; i < hashsize; i++) { INIT_LIST_HEAD(&nn->drc_hashtbl[i].lru_head); spin_lock_init(&nn->drc_hashtbl[i].cache_lock);
@@ -193,8 +197,11 @@ int nfsd_reply_cache_init(struct nfsd_net *nn) nn->drc_hashsize = hashsize; return 0; + +out_register: + shrinker_free(nn->nfsd_reply_cache_shrinker); out_shrinker: - unregister_shrinker(&nn->nfsd_reply_cache_shrinker); + kvfree(nn->drc_hashtbl); out_stats_destroy: nfsd_reply_cache_stats_destroy(nn); out_nomem:
@@ -207,7 +214,7 @@ void nfsd_reply_cache_shutdown(struct nfsd_net *nn) struct svc_cacherep *rp; unsigned int i; - unregister_shrinker(&nn->nfsd_reply_cache_shrinker); + unregister_and_free_shrinker(nn->nfsd_reply_cache_shrinker); for (i = 0; i < nn->drc_hashsize; i++) { struct list_head *head = &nn->drc_hashtbl[i].lru_head;
@@ -297,8 +304,7 @@ prune_cache_entries(struct nfsd_net *nn) static unsigned long nfsd_reply_cache_count(struct shrinker *shrink, struct shrink_control *sc) { - struct nfsd_net *nn = container_of(shrink, - struct nfsd_net, nfsd_reply_cache_shrinker); + struct nfsd_net *nn = shrink->private_data; return atomic_read(&nn->num_drc_entries); }
@@ -306,8 +312,7 @@ nfsd_reply_cache_count(struct shrinker *shrink, struct shrink_control *sc) static unsigned long nfsd_reply_cache_scan(struct shrinker *shrink, struct shrink_control *sc) { - struct nfsd_net *nn = container_of(shrink, - struct nfsd_net, nfsd_reply_cache_shrinker); + struct nfsd_net *nn = shrink->private_data; return prune_cache_entries(nn); }
--
2.30.2