xfs: simplify and remove xfs_ireclaim

xfs_ireclaim has to get and put te pag structure because it is only
called with the inode to reclaim. The one caller of this function
already has a reference on the pag and a pointer to is, so move the
radix tree delete to the caller and remove xfs_ireclaim completely.
This avoids a xfs_perag_get/put on every inode being reclaimed.

The overhead was noticed in a bug report at:

https://bugzilla.kernel.org/show_bug.cgi?id=16348

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

3 files changed, 32 insertions, 54 deletions

diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index 66cefb27438..dfcbd98d159 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -855,7 +855,36 @@ out:
 reclaim:
         xfs_ifunlock(ip);
         xfs_iunlock(ip, XFS_ILOCK_EXCL);
-        xfs_ireclaim(ip);
+
+        XFS_STATS_INC(xs_ig_reclaims);
+        /*
+         * Remove the inode from the per-AG radix tree.
+         *
+         * Because radix_tree_delete won't complain even if the item was never
+         * added to the tree assert that it's been there before to catch
+         * problems with the inode life time early on.
+         */
+        write_lock(&pag->pag_ici_lock);
+        if (!radix_tree_delete(&pag->pag_ici_root,
+                                XFS_INO_TO_AGINO(ip->i_mount, ip->i_ino)))
+                ASSERT(0);
+        write_unlock(&pag->pag_ici_lock);
+
+        /*
+         * Here we do an (almost) spurious inode lock in order to coordinate
+         * with inode cache radix tree lookups.  This is because the lookup
+         * can reference the inodes in the cache without taking references.
+         *
+         * We make that OK here by ensuring that we wait until the inode is
+         * unlocked after the lookup before we go ahead and free it.  We get
+         * both the ilock and the iolock because the code may need to drop the
+         * ilock one but will still hold the iolock.
+         */
+        xfs_ilock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
+        xfs_qm_dqdetach(ip);
+        xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
+
+        xfs_inode_free(ip);
         return error;
 
 }
diff --git a/fs/xfs/xfs_iget.c b/fs/xfs/xfs_iget.c
index 9e86f2116aa..eba5ae61d36 100644
--- a/fs/xfs/xfs_iget.c
+++ b/fs/xfs/xfs_iget.c
@@ -91,7 +91,7 @@ xfs_inode_alloc(
         return ip;
 }
 
-STATIC void
+void
 xfs_inode_free(
         struct xfs_inode        *ip)
 {
@@ -418,57 +418,6 @@ out_error_or_again:
 }
 
 /*
- * This is called free all the memory associated with an inode.
- * It must free the inode itself and any buffers allocated for
- * if_extents/if_data and if_broot.  It must also free the lock
- * associated with the inode.
- *
- * Note: because we don't initialise everything on reallocation out
- * of the zone, we must ensure we nullify everything correctly before
- * freeing the structure.
- */
-void
-xfs_ireclaim(
-        struct xfs_inode        *ip)
-{
-        struct xfs_mount        *mp = ip->i_mount;
-        struct xfs_perag        *pag;
-        xfs_agino_t             agino = XFS_INO_TO_AGINO(mp, ip->i_ino);
-
-        XFS_STATS_INC(xs_ig_reclaims);
-
-        /*
-         * Remove the inode from the per-AG radix tree.
-         *
-         * Because radix_tree_delete won't complain even if the item was never
-         * added to the tree assert that it's been there before to catch
-         * problems with the inode life time early on.
-         */
-        pag = xfs_perag_get(mp, XFS_INO_TO_AGNO(mp, ip->i_ino));
-        write_lock(&pag->pag_ici_lock);
-        if (!radix_tree_delete(&pag->pag_ici_root, agino))
-                ASSERT(0);
-        write_unlock(&pag->pag_ici_lock);
-        xfs_perag_put(pag);
-
-        /*
-         * Here we do an (almost) spurious inode lock in order to coordinate
-         * with inode cache radix tree lookups.  This is because the lookup
-         * can reference the inodes in the cache without taking references.
-         *
-         * We make that OK here by ensuring that we wait until the inode is
-         * unlocked after the lookup before we go ahead and free it.  We get
-         * both the ilock and the iolock because the code may need to drop the
-         * ilock one but will still hold the iolock.
-         */
-        xfs_ilock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
-        xfs_qm_dqdetach(ip);
-        xfs_iunlock(ip, XFS_ILOCK_EXCL | XFS_IOLOCK_EXCL);
-
-        xfs_inode_free(ip);
-}
-
-/*
  * This is a wrapper routine around the xfs_ilock() routine
  * used to centralize some grungy code.  It is used in places
  * that wish to lock the inode solely for reading the extents.
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index eb41559ea8c..0898c5417d1 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -450,7 +450,7 @@ void		xfs_ilock_demote(xfs_inode_t *, uint);
 int             xfs_isilocked(xfs_inode_t *, uint);
 uint            xfs_ilock_map_shared(xfs_inode_t *);
 void            xfs_iunlock_map_shared(xfs_inode_t *, uint);
-void            xfs_ireclaim(xfs_inode_t *);
+void            xfs_inode_free(struct xfs_inode *ip);
 
 /*
  * xfs_inode.c prototypes.