Commit f8806c84 authored Aug 05, 2013 by Trond Myklebust

NFS: Fix writeback performance issue on cache invalidation



If a cache invalidation is triggered, and we happen to have a lot of
writebacks cached at the time, then the call to invalidate_inode_pages2()
will end up calling ->launder_page() on each and every dirty page in order
to sync its contents to disk, thus defeating write coalescing.
The following patch ensures that we try to sync the inode to disk before
calling invalidate_inode_pages2() so that we do the writeback as efficiently
as possible.

Reported-by: William Dauchy <william@gandi.net>
Reported-by: Pascal Bouchareine <pascal@gandi.net>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Tested-by: William Dauchy <william@gandi.net>
Reviewed-by: Jeff Layton <jlayton@redhat.com>

parent 786615bc

fs/nfs/inode.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -963,9 +963,15 @@ EXPORT_SYMBOL_GPL(nfs_revalidate_inode);
		static int nfs_invalidate_mapping(struct inode inode, struct address_space mapping)
		{
		struct nfs_inode *nfsi = NFS_I(inode);
		int ret;

		if (mapping->nrpages != 0) {
		int ret = invalidate_inode_pages2(mapping);
		if (S_ISREG(inode->i_mode)) {
		ret = nfs_sync_mapping(mapping);
		if (ret < 0)
		return ret;
		}
		ret = invalidate_inode_pages2(mapping);
		if (ret < 0)
		return ret;
		}

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