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c=relaxed/simple; d=kernel.org; s=k20201202; t=1690201076; bh=SgqvEHTSsoLx88OM4JQmZh6whPE6BGZ/uEOL9QxuZhc=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=HeauOjdE48WDStWMcmbZe0QJCu1PZbrw2jnOfPPp5Y0n0Q1TK60SYgINluh0tVUHu HMa9pGy9YrA2Xid5ZQCkD41aahatrfHq9vVHLjbuzLzQBP/bIUW5s/kQBvStLkPbEr 52wVvvm4TuW1EIIyQppWxFYEv7SoUq895jOWh1zWA+5Bhuu0CwPKUfnKQ6aPaR+FNu w4bgci3LfqcgT2vztkyr4DzF2/4Hyf1LGlp6Z0shJe1d8GJLzPQbDhc3dh09sCIq3l N9zzfqaN5HsWy8Vmt4P1E7EQFqQrkFrxcJ7/1W6yEYc3GiEERam+zZN0XSQm/ELIIc 3urjqaifuO8iw== Message-ID: Subject: Re: [PATCH v2 35/47] nfsd: dynamically allocate the nfsd-reply shrinker From: Jeff Layton To: Qi Zheng , 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, steven.price@arm.com, cel@kernel.org, senozhatsky@chromium.org, yujie.liu@intel.com, gregkh@linuxfoundation.org, muchun.song@linux.dev Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, linux-erofs@lists.ozlabs.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-nfs@vger.kernel.org, linux-mtd@lists.infradead.org, rcu@vger.kernel.org, netdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-bcache@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org, linux-btrfs@vger.kernel.org, Chuck Lever Date: Mon, 24 Jul 2023 08:17:52 -0400 In-Reply-To: <20230724094354.90817-36-zhengqi.arch@bytedance.com> References: <20230724094354.90817-1-zhengqi.arch@bytedance.com> <20230724094354.90817-36-zhengqi.arch@bytedance.com> Content-Type: text/plain; charset="ISO-8859-15" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.48.4 (3.48.4-1.fc38) MIME-Version: 1.0 X-Rspamd-Queue-Id: 2F1AD4000C X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: 7t9ky3hjtxp6azjf9ecprt1yzxuscoy9 X-HE-Tag: 1690201077-355871 X-HE-Meta: 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 gdSAHWds 9MJrrdUlxSmaoDW3GxsaGNtKE7MRG9hkpg6rwGtZoq3e6SwkhhoCCWmsZnRdq1Ry4Sa1EDzejLtD6con/FUxF+eurgWBsrrylrAIvmtKtGr0Dj4vmClWKZtoGHxfdSK0N38nRW9WlUwR1wLaPzj4Rx0mF6FuC6XFXwnaiG1bWwjzoeniYT9dN2PLTyrmq+Xxv4qbRC730QHVzGmjUveGiYDwtIAKciVWdqS5uoLULA5jpwIBiIa2ITzLOjTayBs1DyXaTUGdmpnRT5pzXH91gs4CqGmCyXHzpTIxGRpxXgC13RBl24JO8dyX9cuiRL700dbtsUB2rV9KUDqdkaHG/0Qwqaez7OqSs6MIKvjPJLUt39yMIbtY9aG3DpdiuKgscGvyc4fr2nuZ7c2qZEsUOeFSVe48HuL/HzL/mik95SN6q4PcZKEQqjd2r3w== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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. >=20 > Acked-by: Chuck Lever > Signed-off-by: Qi Zheng > --- > fs/nfsd/netns.h | 2 +- > fs/nfsd/nfscache.c | 31 ++++++++++++++++--------------- > 2 files changed, 17 insertions(+), 16 deletions(-) >=20 > 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; > =20 > - struct shrinker nfsd_reply_cache_shrinker; > + struct shrinker *nfsd_reply_cache_shrinker; > =20 > /* 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 =3D 0; > =20 > nn->max_drc_entries =3D nfsd_cache_size_limit(); > atomic_set(&nn->num_drc_entries, 0); > hashsize =3D nfsd_hashsize(nn->max_drc_entries); > nn->maskbits =3D ilog2(hashsize); > =20 > - nn->nfsd_reply_cache_shrinker.scan_objects =3D nfsd_reply_cache_scan; > - nn->nfsd_reply_cache_shrinker.count_objects =3D nfsd_reply_cache_count; > - nn->nfsd_reply_cache_shrinker.seeks =3D 1; > - status =3D register_shrinker(&nn->nfsd_reply_cache_shrinker, > - "nfsd-reply:%s", nn->nfsd_name); > - if (status) > - return status; > - > nn->drc_hashtbl =3D kvzalloc(array_size(hashsize, > sizeof(*nn->drc_hashtbl)), GFP_KERNEL); > if (!nn->drc_hashtbl) > + return -ENOMEM; > + > + nn->nfsd_reply_cache_shrinker =3D shrinker_alloc(0, "nfsd-reply:%s", > + nn->nfsd_name); > + if (!nn->nfsd_reply_cache_shrinker) > goto out_shrinker; > =20 > + nn->nfsd_reply_cache_shrinker->scan_objects =3D nfsd_reply_cache_scan; > + nn->nfsd_reply_cache_shrinker->count_objects =3D nfsd_reply_cache_count= ; > + nn->nfsd_reply_cache_shrinker->seeks =3D 1; > + nn->nfsd_reply_cache_shrinker->private_data =3D nn; > + > + shrinker_register(nn->nfsd_reply_cache_shrinker); > + > for (i =3D 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) > =20 > 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; > =20 > - unregister_shrinker(&nn->nfsd_reply_cache_shrinker); > + shrinker_unregister(nn->nfsd_reply_cache_shrinker); > =20 > for (i =3D 0; i < nn->drc_hashsize; i++) { > struct list_head *head =3D &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 *s= c) > { > - struct nfsd_net *nn =3D container_of(shrink, > - struct nfsd_net, nfsd_reply_cache_shrinker); > + struct nfsd_net *nn =3D shrink->private_data; > =20 > return atomic_read(&nn->num_drc_entries); > } > @@ -342,8 +344,7 @@ nfsd_reply_cache_count(struct shrinker *shrink, struc= t shrink_control *sc) > static unsigned long > nfsd_reply_cache_scan(struct shrinker *shrink, struct shrink_control *sc= ) > { > - struct nfsd_net *nn =3D container_of(shrink, > - struct nfsd_net, nfsd_reply_cache_shrinker); > + struct nfsd_net *nn =3D shrink->private_data; > unsigned long freed =3D 0; > LIST_HEAD(dispose); > unsigned int i; Acked-by: Jeff Layton