Commit 82749dd4 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Reduce lock contention in nfs_page_find_head_request() 



Add a lockless check for whether or not the page might be carrying
an existing writeback before we grab the inode->i_lock.

Reported-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 6d17d653

fs/nfs/write.c

+5 −3
Original line number Diff line number Diff line
@@ -190,9 +190,11 @@ static struct nfs_page *nfs_page_find_head_request(struct page *page) 
	struct inode *inode = page_file_mapping(page)->host;

	struct nfs_page *req = NULL;



	if (PagePrivate(page) || PageSwapCache(page)) {

		spin_lock(&inode->i_lock);

		req = nfs_page_find_head_request_locked(NFS_I(inode), page);

		spin_unlock(&inode->i_lock);

	}

	return req;

}

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