From: Trond Myklebust <trondmy@gmail.com>
To: linux-nfs@vger.kernel.org
Subject: [PATCH 3/7] NFS: Convert lookups of the lock context to RCU
Date: Wed, 5 Sep 2018 15:23:56 -0400 [thread overview]
Message-ID: <20180905192400.107485-4-trond.myklebust@hammerspace.com> (raw)
In-Reply-To: <20180905192400.107485-3-trond.myklebust@hammerspace.com>
Speed up lookups of an existing lock context by avoiding the inode->i_lock,
and using RCU instead.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
fs/nfs/inode.c | 25 ++++++++++++-------------
include/linux/nfs_fs.h | 1 +
2 files changed, 13 insertions(+), 13 deletions(-)
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index b65aee481d13..09b3b7146ff4 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -857,15 +857,14 @@ static void nfs_init_lock_context(struct nfs_lock_context *l_ctx)
static struct nfs_lock_context *__nfs_find_lock_context(struct nfs_open_context *ctx)
{
- struct nfs_lock_context *head = &ctx->lock_context;
- struct nfs_lock_context *pos = head;
+ struct nfs_lock_context *pos;
- do {
+ list_for_each_entry_rcu(pos, &ctx->lock_context.list, list) {
if (pos->lockowner != current->files)
continue;
- refcount_inc(&pos->count);
- return pos;
- } while ((pos = list_entry(pos->list.next, typeof(*pos), list)) != head);
+ if (refcount_inc_not_zero(&pos->count))
+ return pos;
+ }
return NULL;
}
@@ -874,10 +873,10 @@ struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx)
struct nfs_lock_context *res, *new = NULL;
struct inode *inode = d_inode(ctx->dentry);
- spin_lock(&inode->i_lock);
+ rcu_read_lock();
res = __nfs_find_lock_context(ctx);
+ rcu_read_unlock();
if (res == NULL) {
- spin_unlock(&inode->i_lock);
new = kmalloc(sizeof(*new), GFP_KERNEL);
if (new == NULL)
return ERR_PTR(-ENOMEM);
@@ -885,14 +884,14 @@ struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx)
spin_lock(&inode->i_lock);
res = __nfs_find_lock_context(ctx);
if (res == NULL) {
- list_add_tail(&new->list, &ctx->lock_context.list);
+ list_add_tail_rcu(&new->list, &ctx->lock_context.list);
new->open_context = ctx;
res = new;
new = NULL;
}
+ spin_unlock(&inode->i_lock);
+ kfree(new);
}
- spin_unlock(&inode->i_lock);
- kfree(new);
return res;
}
EXPORT_SYMBOL_GPL(nfs_get_lock_context);
@@ -904,9 +903,9 @@ void nfs_put_lock_context(struct nfs_lock_context *l_ctx)
if (!refcount_dec_and_lock(&l_ctx->count, &inode->i_lock))
return;
- list_del(&l_ctx->list);
+ list_del_rcu(&l_ctx->list);
spin_unlock(&inode->i_lock);
- kfree(l_ctx);
+ kfree_rcu(l_ctx, rcu_head);
}
EXPORT_SYMBOL_GPL(nfs_put_lock_context);
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index a0831e9d19c9..d2f4f88a0e66 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -62,6 +62,7 @@ struct nfs_lock_context {
struct nfs_open_context *open_context;
fl_owner_t lockowner;
atomic_t io_count;
+ struct rcu_head rcu_head;
};
struct nfs4_state;
--
2.17.1
next prev parent reply other threads:[~2018-09-05 23:56 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-05 19:23 [PATCH 0/7] Misc NFS + pNFS performance enhancements Trond Myklebust
2018-09-05 19:23 ` [PATCH 1/7] pNFS: Don't zero out the array in nfs4_alloc_pages() Trond Myklebust
2018-09-05 19:23 ` [PATCH 2/7] pNFS: Don't allocate more pages than we need to fit a layoutget response Trond Myklebust
2018-09-05 19:23 ` Trond Myklebust [this message]
2018-09-05 19:23 ` [PATCH 4/7] NFS: Simplify internal check for whether file is open for write Trond Myklebust
2018-09-05 19:23 ` [PATCH 5/7] NFS: Convert lookups of the open context to RCU Trond Myklebust
2018-09-05 19:23 ` [PATCH 6/7] NFSv4: Convert open state lookup to use RCU Trond Myklebust
2018-09-05 19:24 ` [PATCH 7/7] NFSv4: Convert struct nfs4_state to use refcount_t Trond Myklebust
2018-09-28 16:34 ` [PATCH 5/7] NFS: Convert lookups of the open context to RCU Olga Kornievskaia
2018-09-28 16:54 ` Olga Kornievskaia
2018-09-28 17:49 ` Trond Myklebust
2018-09-28 18:31 ` Olga Kornievskaia
2018-09-28 18:53 ` Trond Myklebust
2018-09-28 19:10 ` Olga Kornievskaia
2018-09-28 19:55 ` Olga Kornievskaia
2018-09-28 20:07 ` Trond Myklebust
2018-09-28 20:19 ` Olga Kornievskaia
2018-09-28 20:38 ` Trond Myklebust
2018-10-03 18:38 ` Olga Kornievskaia
2018-10-04 15:22 ` Trond Myklebust
2018-10-04 15:49 ` Olga Kornievskaia
2018-10-04 16:13 ` Trond Myklebust
2018-10-04 16:31 ` Olga Kornievskaia
2018-10-04 16:42 ` Trond Myklebust
2018-10-04 18:51 ` Olga Kornievskaia
2018-10-03 22:05 ` [PATCH 2/7] pNFS: Don't allocate more pages than we need to fit a layoutget response NeilBrown
2018-09-05 19:33 ` [PATCH 0/7] Misc NFS + pNFS performance enhancements Chuck Lever
2018-09-05 20:36 ` Trond Myklebust
2018-09-07 15:44 ` Chuck Lever
2018-09-10 1:35 ` Trond Myklebust
2018-09-10 16:14 ` Chuck Lever
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