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authorTrond Myklebust <trond.myklebust@primarydata.com>2017-07-17 09:37:12 -0400
committerTrond Myklebust <trond.myklebust@primarydata.com>2017-08-15 11:54:46 -0400
commit1403390d8366c717139cab26b8e94d943915fa12 (patch)
tree4a254482b5f730f0927b88c0fafca3361b7f9235 /fs/nfs
parent82749dd4efcec8e90fa7769eec3dd0afa2e3396a (diff)
NFS: Reduce lock contention in nfs_try_to_update_request()
Micro-optimisation to move the lockless check into the for(;;) loop. Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs/nfs')
-rw-r--r--fs/nfs/write.c8
1 files changed, 3 insertions, 5 deletions
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 06e150c4e315..bb019096c331 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -1097,13 +1097,12 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
unsigned int end;
int error;
- if (!PagePrivate(page))
- return NULL;
-
end = offset + bytes;
- spin_lock(&inode->i_lock);
for (;;) {
+ if (!(PagePrivate(page) || PageSwapCache(page)))
+ return NULL;
+ spin_lock(&inode->i_lock);
req = nfs_page_find_head_request_locked(NFS_I(inode), page);
if (req == NULL)
goto out_unlock;
@@ -1132,7 +1131,6 @@ static struct nfs_page *nfs_try_to_update_request(struct inode *inode,
nfs_release_request(req);
if (error != 0)
goto out_err;
- spin_lock(&inode->i_lock);
}
/* Okay, the request matches. Update the region */