patch-2.4.25 linux-2.4.25/fs/xfs/xfs_refcache.c

• Lines: 440
• Date: 2004-02-18 05:36:32.000000000 -0800
• Orig file: linux-2.4.24/fs/xfs/xfs_refcache.c
• Orig date: 1969-12-31 16:00:00.000000000 -0800

diff -urN linux-2.4.24/fs/xfs/xfs_refcache.c linux-2.4.25/fs/xfs/xfs_refcache.c
@@ -0,0 +1,439 @@
+/*
+ * Copyright (c) 2000-2003 Silicon Graphics, Inc.  All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of version 2 of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * Further, this software is distributed without any warranty that it is
+ * free of the rightful claim of any third person regarding infringement
+ * or the like.  Any license provided herein, whether implied or
+ * otherwise, applies only to this software file.  Patent licenses, if
+ * any, provided herein do not apply to combinations of this program with
+ * other software, or any other product whatsoever.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ * Contact information: Silicon Graphics, Inc., 1600 Amphitheatre Pkwy,
+ * Mountain View, CA  94043, or:
+ *
+ * http://www.sgi.com
+ *
+ * For further information regarding this notice, see:
+ *
+ * http://oss.sgi.com/projects/GenInfo/SGIGPLNoticeExplan/
+ */
+
+#include "xfs.h"
+#include "xfs_macros.h"
+#include "xfs_types.h"
+#include "xfs_inum.h"
+#include "xfs_log.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_ag.h"
+#include "xfs_dir.h"
+#include "xfs_dir2.h"
+#include "xfs_dmapi.h"
+#include "xfs_mount.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_ialloc_btree.h"
+#include "xfs_itable.h"
+#include "xfs_btree.h"
+#include "xfs_alloc.h"
+#include "xfs_ialloc.h"
+#include "xfs_attr.h"
+#include "xfs_attr_sf.h"
+#include "xfs_dir_sf.h"
+#include "xfs_dir2_sf.h"
+#include "xfs_dinode.h"
+#include "xfs_inode_item.h"
+#include "xfs_inode.h"
+#include "xfs_bmap.h"
+#include "xfs_error.h"
+#include "xfs_buf_item.h"
+#include "xfs_refcache.h"
+
+STATIC spinlock_t	xfs_refcache_lock = SPIN_LOCK_UNLOCKED;
+STATIC xfs_inode_t	**xfs_refcache;
+STATIC int		xfs_refcache_index;
+STATIC int		xfs_refcache_busy;
+STATIC int		xfs_refcache_count;
+
+/*
+ * Insert the given inode into the reference cache.
+ */
+void
+xfs_refcache_insert(
+	xfs_inode_t	*ip)
+{
+	vnode_t		*vp;
+	xfs_inode_t	*release_ip;
+	xfs_inode_t	**refcache;
+
+	ASSERT(ismrlocked(&(ip->i_iolock), MR_UPDATE));
+
+	/*
+	 * If an unmount is busy blowing entries out of the cache,
+	 * then don't bother.
+	 */
+	if (xfs_refcache_busy) {
+		return;
+	}
+
+	/*
+	 * If we tuned the refcache down to zero, don't do anything.
+	 */
+	 if (!xfs_refcache_size) {
+		return;
+	}
+
+	/*
+	 * The inode is already in the refcache, so don't bother
+	 * with it.
+	 */
+	if (ip->i_refcache != NULL) {
+		return;
+	}
+
+	vp = XFS_ITOV(ip);
+	/* ASSERT(vp->v_count > 0); */
+	VN_HOLD(vp);
+
+	/*
+	 * We allocate the reference cache on use so that we don't
+	 * waste the memory on systems not being used as NFS servers.
+	 */
+	if (xfs_refcache == NULL) {
+		refcache = (xfs_inode_t **)kmem_zalloc(XFS_REFCACHE_SIZE_MAX *
+						       sizeof(xfs_inode_t *),
+						       KM_SLEEP);
+	} else {
+		refcache = NULL;
+	}
+
+	spin_lock(&xfs_refcache_lock);
+
+	/*
+	 * If we allocated memory for the refcache above and it still
+	 * needs it, then use the memory we allocated.  Otherwise we'll
+	 * free the memory below.
+	 */
+	if (refcache != NULL) {
+		if (xfs_refcache == NULL) {
+			xfs_refcache = refcache;
+			refcache = NULL;
+		}
+	}
+
+	/*
+	 * If an unmount is busy clearing out the cache, don't add new
+	 * entries to it.
+	 */
+	if (xfs_refcache_busy) {
+		spin_unlock(&xfs_refcache_lock);
+		VN_RELE(vp);
+		/*
+		 * If we allocated memory for the refcache above but someone
+		 * else beat us to using it, then free the memory now.
+		 */
+		if (refcache != NULL) {
+			kmem_free(refcache,
+				  XFS_REFCACHE_SIZE_MAX * sizeof(xfs_inode_t *));
+		}
+		return;
+	}
+	release_ip = xfs_refcache[xfs_refcache_index];
+	if (release_ip != NULL) {
+		release_ip->i_refcache = NULL;
+		xfs_refcache_count--;
+		ASSERT(xfs_refcache_count >= 0);
+	}
+	xfs_refcache[xfs_refcache_index] = ip;
+	ASSERT(ip->i_refcache == NULL);
+	ip->i_refcache = &(xfs_refcache[xfs_refcache_index]);
+	xfs_refcache_count++;
+	ASSERT(xfs_refcache_count <= xfs_refcache_size);
+	xfs_refcache_index++;
+	if (xfs_refcache_index == xfs_refcache_size) {
+		xfs_refcache_index = 0;
+	}
+	spin_unlock(&xfs_refcache_lock);
+
+	/*
+	 * Save the pointer to the inode to be released so that we can
+	 * VN_RELE it once we've dropped our inode locks in xfs_rwunlock().
+	 * The pointer may be NULL, but that's OK.
+	 */
+	ip->i_release = release_ip;
+
+	/*
+	 * If we allocated memory for the refcache above but someone
+	 * else beat us to using it, then free the memory now.
+	 */
+	if (refcache != NULL) {
+		kmem_free(refcache,
+			  XFS_REFCACHE_SIZE_MAX * sizeof(xfs_inode_t *));
+	}
+}
+
+
+/*
+ * If the given inode is in the reference cache, purge its entry and
+ * release the reference on the vnode.
+ */
+void
+xfs_refcache_purge_ip(
+	xfs_inode_t	*ip)
+{
+	vnode_t	*vp;
+	int	error;
+
+	/*
+	 * If we're not pointing to our entry in the cache, then
+	 * we must not be in the cache.
+	 */
+	if (ip->i_refcache == NULL) {
+		return;
+	}
+
+	spin_lock(&xfs_refcache_lock);
+	if (ip->i_refcache == NULL) {
+		spin_unlock(&xfs_refcache_lock);
+		return;
+	}
+
+	/*
+	 * Clear both our pointer to the cache entry and its pointer
+	 * back to us.
+	 */
+	ASSERT(*(ip->i_refcache) == ip);
+	*(ip->i_refcache) = NULL;
+	ip->i_refcache = NULL;
+	xfs_refcache_count--;
+	ASSERT(xfs_refcache_count >= 0);
+	spin_unlock(&xfs_refcache_lock);
+
+	vp = XFS_ITOV(ip);
+	/* ASSERT(vp->v_count > 1); */
+	VOP_RELEASE(vp, error);
+	VN_RELE(vp);
+}
+
+
+/*
+ * This is called from the XFS unmount code to purge all entries for the
+ * given mount from the cache.  It uses the refcache busy counter to
+ * make sure that new entries are not added to the cache as we purge them.
+ */
+void
+xfs_refcache_purge_mp(
+	xfs_mount_t	*mp)
+{
+	vnode_t		*vp;
+	int		error, i;
+	xfs_inode_t	*ip;
+
+	if (xfs_refcache == NULL) {
+		return;
+	}
+
+	spin_lock(&xfs_refcache_lock);
+	/*
+	 * Bumping the busy counter keeps new entries from being added
+	 * to the cache.  We use a counter since multiple unmounts could
+	 * be in here simultaneously.
+	 */
+	xfs_refcache_busy++;
+
+	for (i = 0; i < xfs_refcache_size; i++) {
+		ip = xfs_refcache[i];
+		if ((ip != NULL) && (ip->i_mount == mp)) {
+			xfs_refcache[i] = NULL;
+			ip->i_refcache = NULL;
+			xfs_refcache_count--;
+			ASSERT(xfs_refcache_count >= 0);
+			spin_unlock(&xfs_refcache_lock);
+			vp = XFS_ITOV(ip);
+			VOP_RELEASE(vp, error);
+			VN_RELE(vp);
+			spin_lock(&xfs_refcache_lock);
+		}
+	}
+
+	xfs_refcache_busy--;
+	ASSERT(xfs_refcache_busy >= 0);
+	spin_unlock(&xfs_refcache_lock);
+}
+
+
+/*
+ * This is called from the XFS sync code to ensure that the refcache
+ * is emptied out over time.  We purge a small number of entries with
+ * each call.
+ */
+void
+xfs_refcache_purge_some(xfs_mount_t *mp)
+{
+	int		error, i;
+	xfs_inode_t	*ip;
+	int		iplist_index;
+	xfs_inode_t	**iplist;
+
+	if ((xfs_refcache == NULL) || (xfs_refcache_count == 0)) {
+		return;
+	}
+
+	iplist_index = 0;
+	iplist = (xfs_inode_t **)kmem_zalloc(xfs_refcache_purge_count *
+					  sizeof(xfs_inode_t *), KM_SLEEP);
+
+	spin_lock(&xfs_refcache_lock);
+
+	/*
+	 * Store any inodes we find in the next several entries
+	 * into the iplist array to be released after dropping
+	 * the spinlock.  We always start looking from the currently
+	 * oldest place in the cache.  We move the refcache index
+	 * forward as we go so that we are sure to eventually clear
+	 * out the entire cache when the system goes idle.
+	 */
+	for (i = 0; i < xfs_refcache_purge_count; i++) {
+		ip = xfs_refcache[xfs_refcache_index];
+		if (ip != NULL) {
+			xfs_refcache[xfs_refcache_index] = NULL;
+			ip->i_refcache = NULL;
+			xfs_refcache_count--;
+			ASSERT(xfs_refcache_count >= 0);
+			iplist[iplist_index] = ip;
+			iplist_index++;
+		}
+		xfs_refcache_index++;
+		if (xfs_refcache_index == xfs_refcache_size) {
+			xfs_refcache_index = 0;
+		}
+	}
+
+	spin_unlock(&xfs_refcache_lock);
+
+	/*
+	 * Now drop the inodes we collected.
+	 */
+	for (i = 0; i < iplist_index; i++) {
+		VOP_RELEASE(XFS_ITOV(iplist[i]), error);
+		VN_RELE(XFS_ITOV(iplist[i]));
+	}
+
+	kmem_free(iplist, xfs_refcache_purge_count *
+			  sizeof(xfs_inode_t *));
+}
+
+/*
+ * This is called when the refcache is dynamically resized
+ * via a sysctl.
+ *
+ * If the new size is smaller than the old size, purge all
+ * entries in slots greater than the new size, and move
+ * the index if necessary.
+ *
+ * If the refcache hasn't even been allocated yet, or the
+ * new size is larger than the old size, just set the value
+ * of xfs_refcache_size.
+ */
+
+void
+xfs_refcache_resize(int xfs_refcache_new_size)
+{
+	int		i;
+	xfs_inode_t	*ip;
+	int		iplist_index = 0;
+	xfs_inode_t	**iplist;
+	int		error;
+
+	/*
+	 * If the new size is smaller than the current size,
+	 * purge entries to create smaller cache, and
+	 * reposition index if necessary.
+	 * Don't bother if no refcache yet.
+	 */
+	if (xfs_refcache && (xfs_refcache_new_size < xfs_refcache_size)) {
+
+		iplist = (xfs_inode_t **)kmem_zalloc(XFS_REFCACHE_SIZE_MAX *
+				sizeof(xfs_inode_t *), KM_SLEEP);
+
+		spin_lock(&xfs_refcache_lock);
+
+		for (i = xfs_refcache_new_size; i < xfs_refcache_size; i++) {
+			ip = xfs_refcache[i];
+			if (ip != NULL) {
+				xfs_refcache[i] = NULL;
+				ip->i_refcache = NULL;
+				xfs_refcache_count--;
+				ASSERT(xfs_refcache_count >= 0);
+				iplist[iplist_index] = ip;
+				iplist_index++;
+			}
+		}
+
+		xfs_refcache_size = xfs_refcache_new_size;
+
+		/*
+		 * Move index to beginning of cache if it's now past the end
+		 */
+		if (xfs_refcache_index >= xfs_refcache_new_size)
+			xfs_refcache_index = 0;
+
+		spin_unlock(&xfs_refcache_lock);
+
+		/*
+		 * Now drop the inodes we collected.
+		 */
+		for (i = 0; i < iplist_index; i++) {
+			VOP_RELEASE(XFS_ITOV(iplist[i]), error);
+			VN_RELE(XFS_ITOV(iplist[i]));
+		}
+
+		kmem_free(iplist, XFS_REFCACHE_SIZE_MAX *
+				  sizeof(xfs_inode_t *));
+	} else {
+		spin_lock(&xfs_refcache_lock);
+		xfs_refcache_size = xfs_refcache_new_size;
+		spin_unlock(&xfs_refcache_lock);
+	}
+}
+
+void
+xfs_refcache_iunlock(
+	xfs_inode_t	*ip,
+	uint		lock_flags)
+{
+	xfs_inode_t	*release_ip;
+	int		error;
+
+	release_ip = ip->i_release;
+	ip->i_release = NULL;
+
+	xfs_iunlock(ip, lock_flags);
+
+	if (release_ip != NULL) {
+		VOP_RELEASE(XFS_ITOV(release_ip), error);
+		VN_RELE(XFS_ITOV(release_ip));
+	}
+}
+
+void
+xfs_refcache_destroy(void)
+{
+	if (xfs_refcache) {
+		kmem_free(xfs_refcache,
+			XFS_REFCACHE_SIZE_MAX * sizeof(xfs_inode_t *));
+		xfs_refcache = NULL;
+	}
+}