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Commit 71bce256 authored by Nathan Scott's avatar Nathan Scott Committed by Christoph Hellwig
Browse files

[XFS] Move the XFS inode to the front of its hash list on a cache hit 



SGI Modid: xfs-linux:xfs-kern:21915a

Signed-off-by: default avatarNathan Scott <nathans@sgi.com>
Signed-off-by: default avatarChristoph Hellwig <hch@sgi.com>
parent bfd4bda0

fs/xfs/xfs_iget.c

+50 −1
Original line number Diff line number Diff line
@@ -135,6 +135,40 @@ xfs_chash_free(xfs_mount_t *mp) 
	mp->m_chash = NULL;

}



/*

 * Try to move an inode to the front of its hash list if possible

 * (and if its not there already).  Called right after obtaining

 * the list version number and then dropping the read_lock on the

 * hash list in question (which is done right after looking up the

 * inode in question...).

 */

STATIC void

xfs_ihash_promote(

	xfs_ihash_t	*ih,

	xfs_inode_t	*ip,

	ulong		version)

{

	xfs_inode_t	*iq;



	if ((ip->i_prevp != &ih->ih_next) && write_trylock(&ih->ih_lock)) {

		if (likely(version == ih->ih_version)) {

			/* remove from list */

			if ((iq = ip->i_next)) {

				iq->i_prevp = ip->i_prevp;

			}

			*ip->i_prevp = iq;



			/* insert at list head */

			iq = ih->ih_next;

			iq->i_prevp = &ip->i_next;

			ip->i_next = iq;

			ip->i_prevp = &ih->ih_next;

			ih->ih_next = ip;

		}

		write_unlock(&ih->ih_lock);

	}

}



/*

 * Look up an inode by number in the given file system.

 * The inode is looked up in the hash table for the file system
@@ -229,7 +263,9 @@ xfs_iget_core( 
				XFS_STATS_INC(xs_ig_found);



				ip->i_flags &= ~XFS_IRECLAIMABLE;

				version = ih->ih_version;

				read_unlock(&ih->ih_lock);

				xfs_ihash_promote(ih, ip, version);



				XFS_MOUNT_ILOCK(mp);

				list_del_init(&ip->i_reclaim);
@@ -259,8 +295,15 @@ xfs_iget_core( 
						inode_vp, vp);

			}



			/*

			 * Inode cache hit: if ip is not at the front of

			 * its hash chain, move it there now.

			 * Do this with the lock held for update, but

			 * do statistics after releasing the lock.

			 */

			version = ih->ih_version;

			read_unlock(&ih->ih_lock);



			xfs_ihash_promote(ih, ip, version);

			XFS_STATS_INC(xs_ig_found);



finish_inode:
@@ -547,6 +590,7 @@ xfs_inode_incore(xfs_mount_t *mp, 
{

	xfs_ihash_t	*ih;

	xfs_inode_t	*ip;

	ulong		version;



	ih = XFS_IHASH(mp, ino);

	read_lock(&ih->ih_lock);
@@ -554,11 +598,15 @@ xfs_inode_incore(xfs_mount_t *mp, 
		if (ip->i_ino == ino) {

			/*

			 * If we find it and tp matches, return it.

			 * Also move it to the front of the hash list

			 * if we find it and it is not already there.

			 * Otherwise break from the loop and return

			 * NULL.

			 */

			if (ip->i_transp == tp) {

				version = ih->ih_version;

				read_unlock(&ih->ih_lock);

				xfs_ihash_promote(ih, ip, version);

				return (ip);

			}

			break;
@@ -685,6 +733,7 @@ xfs_iextract( 
		iq->i_prevp = ip->i_prevp;

	}

	*ip->i_prevp = iq;

	ih->ih_version++;

	write_unlock(&ih->ih_lock);



	/*