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authorChristoph Hellwig <hch@lst.de>2016-09-19 11:09:48 +1000
committerDave Chinner <david@fromorbit.com>2016-09-19 11:09:48 +1000
commit85a6e764ff5485dfe1edf5e47290e4d32ea866d5 (patch)
tree904f32368131bdff904563606ac31952ddc08d1a
parentf8e3a8257538af8dbdd15d098c0cfba6ccbabe7a (diff)
downloadlinux-85a6e764ff5485dfe1edf5e47290e4d32ea866d5.tar.gz
xfs: make xfs_inode_set_eofblocks_tag cheaper for the common case
For long growing file writes we will usually already have the
eofblocks tag set when adding more speculative preallocations.  Add
a flag in the inode to allow us to skip the the fairly expensive
AG-wide spinlocks and multiple radix tree operations in that case.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>


-rw-r--r--fs/xfs/xfs_icache.c14
-rw-r--r--fs/xfs/xfs_inode.h1
2 files changed, 15 insertions, 0 deletions
diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index fb39a66914dd..65b2e3f85f52 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -1414,6 +1414,16 @@ xfs_inode_set_eofblocks_tag(
 	struct xfs_perag *pag;
 	int tagged;
 
+	/*
+	 * Don't bother locking the AG and looking up in the radix trees
+	 * if we already know that we have the tag set.
+	 */
+	if (ip->i_flags & XFS_IEOFBLOCKS)
+		return;
+	spin_lock(&ip->i_flags_lock);
+	ip->i_flags |= XFS_IEOFBLOCKS;
+	spin_unlock(&ip->i_flags_lock);
+
 	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
 	spin_lock(&pag->pag_ici_lock);
 	trace_xfs_inode_set_eofblocks_tag(ip);
@@ -1449,6 +1459,10 @@ xfs_inode_clear_eofblocks_tag(
 	struct xfs_mount *mp = ip->i_mount;
 	struct xfs_perag *pag;
 
+	spin_lock(&ip->i_flags_lock);
+	ip->i_flags &= ~XFS_IEOFBLOCKS;
+	spin_unlock(&ip->i_flags_lock);
+
 	pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
 	spin_lock(&pag->pag_ici_lock);
 	trace_xfs_inode_clear_eofblocks_tag(ip);
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index e1a411e08f00..8f30d2533b48 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -216,6 +216,7 @@ xfs_get_initial_prid(struct xfs_inode *dp)
 #define __XFS_IPINNED_BIT	8	 /* wakeup key for zero pin count */
 #define XFS_IPINNED		(1 << __XFS_IPINNED_BIT)
 #define XFS_IDONTCACHE		(1 << 9) /* don't cache the inode long term */
+#define XFS_IEOFBLOCKS		(1 << 10)/* has the preallocblocks tag set */
 
 /*
  * Per-lifetime flags need to be reset when re-using a reclaimable inode during