[XFS] Increase the size of the buffer holding the local inode cluster
list, to increase our potential readahead window and in turn improve
bulkstat performance.
SGI-PV: 944409
SGI-Modid: xfs-linux-melb:xfs-kern:26607a
Signed-off-by: Nathan Scott <nathans@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>
diff --git a/fs/xfs/xfs_itable.c b/fs/xfs/xfs_itable.c
index e6dbe6b..315c9bc 100644
--- a/fs/xfs/xfs_itable.c
+++ b/fs/xfs/xfs_itable.c
@@ -324,6 +324,8 @@
xfs_agino_t gino; /* current btree rec's start inode */
int i; /* loop index */
int icount; /* count of inodes good in irbuf */
+ int irbsize; /* size of irec buffer in bytes */
+ unsigned int kmflags; /* flags for allocating irec buffer */
xfs_ino_t ino; /* inode number (filesystem) */
xfs_inobt_rec_incore_t *irbp; /* current irec buffer pointer */
xfs_inobt_rec_incore_t *irbuf; /* start of irec buffer */
@@ -369,12 +371,20 @@
nimask = ~(nicluster - 1);
nbcluster = nicluster >> mp->m_sb.sb_inopblog;
/*
- * Allocate a page-sized buffer for inode btree records.
- * We could try allocating something smaller, but for normal
- * calls we'll always (potentially) need the whole page.
+ * Allocate a local buffer for inode cluster btree records.
+ * This caps our maximum readahead window (so don't be stingy)
+ * but we must handle the case where we can't get a contiguous
+ * multi-page buffer, so we drop back toward pagesize; the end
+ * case we ensure succeeds, via appropriate allocation flags.
*/
- irbuf = kmem_alloc(NBPC, KM_SLEEP);
- nirbuf = NBPC / sizeof(*irbuf);
+ irbsize = NBPP * 4;
+ kmflags = KM_SLEEP | KM_MAYFAIL;
+ while (!(irbuf = kmem_alloc(irbsize, kmflags))) {
+ if ((irbsize >>= 1) <= NBPP)
+ kmflags = KM_SLEEP;
+ }
+ nirbuf = irbsize / sizeof(*irbuf);
+
/*
* Loop over the allocation groups, starting from the last
* inode returned; 0 means start of the allocation group.
@@ -672,7 +682,7 @@
/*
* Done, we're either out of filesystem or space to put the data.
*/
- kmem_free(irbuf, NBPC);
+ kmem_free(irbuf, irbsize);
*ubcountp = ubelem;
if (agno >= mp->m_sb.sb_agcount) {
/*