On Mon, 2023-07-24 at 17:43 +0800, Qi Zheng wrote: > In preparation for implementing lockless slab shrink, use new APIs 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. > > Acked-by: Chuck Lever <chuck.lever@xxxxxxxxxx> > Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> > --- > fs/nfsd/netns.h | 2 +- > fs/nfsd/nfscache.c | 31 ++++++++++++++++--------------- > 2 files changed, 17 insertions(+), 16 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 6eb3d7bdfaf3..9f0ab65e4125 100644 > --- a/fs/nfsd/nfscache.c > +++ b/fs/nfsd/nfscache.c > @@ -200,26 +200,29 @@ int nfsd_reply_cache_init(struct nfsd_net *nn) > { > unsigned int hashsize; > unsigned int i; > - int status = 0; > > nn->max_drc_entries = nfsd_cache_size_limit(); > atomic_set(&nn->num_drc_entries, 0); > hashsize = nfsd_hashsize(nn->max_drc_entries); > nn->maskbits = ilog2(hashsize); > > - 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) > - return status; > - > nn->drc_hashtbl = kvzalloc(array_size(hashsize, > sizeof(*nn->drc_hashtbl)), GFP_KERNEL); > if (!nn->drc_hashtbl) > + return -ENOMEM; > + > + nn->nfsd_reply_cache_shrinker = shrinker_alloc(0, "nfsd-reply:%s", > + nn->nfsd_name); > + if (!nn->nfsd_reply_cache_shrinker) > goto out_shrinker; > > + 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; > + nn->nfsd_reply_cache_shrinker->private_data = nn; > + > + shrinker_register(nn->nfsd_reply_cache_shrinker); > + > for (i = 0; i < hashsize; i++) { > INIT_LIST_HEAD(&nn->drc_hashtbl[i].lru_head); > spin_lock_init(&nn->drc_hashtbl[i].cache_lock); > @@ -228,7 +231,7 @@ int nfsd_reply_cache_init(struct nfsd_net *nn) > > return 0; > out_shrinker: > - unregister_shrinker(&nn->nfsd_reply_cache_shrinker); > + kvfree(nn->drc_hashtbl); > printk(KERN_ERR "nfsd: failed to allocate reply cache\n"); > return -ENOMEM; > } > @@ -238,7 +241,7 @@ void nfsd_reply_cache_shutdown(struct nfsd_net *nn) > struct nfsd_cacherep *rp; > unsigned int i; > > - unregister_shrinker(&nn->nfsd_reply_cache_shrinker); > + shrinker_unregister(nn->nfsd_reply_cache_shrinker); > > for (i = 0; i < nn->drc_hashsize; i++) { > struct list_head *head = &nn->drc_hashtbl[i].lru_head; > @@ -322,8 +325,7 @@ nfsd_prune_bucket_locked(struct nfsd_net *nn, struct nfsd_drc_bucket *b, > 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); > } > @@ -342,8 +344,7 @@ 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; > unsigned long freed = 0; > LIST_HEAD(dispose); > unsigned int i; Acked-by: Jeff Layton <jlayton@xxxxxxxxxx>