From af21ca8ed50f01c5278c5ded6dad6f05e8a5d2e4 Mon Sep 17 00:00:00 2001 From: Bob Peterson Date: Tue, 14 May 2013 13:04:29 -0400 Subject: [PATCH] GFS2: Use single-block reservations for directories This patch changes the multi-block allocation code, such that directory inodes only get a single block reserved in the bitmap. That way, the bitmaps are more tightly packed together, and there are fewer spans of free blocks for in-use block reservations. This means it takes less time to find a free span of blocks in the bitmap, which speeds things up. This increases the performance of some workloads by almost 2X. In Nate's mockup.py script (which does (1) create dir, (2) create dir in dir, (3) create file in that dir) the test executes in 23 steps rather than 43 steps, a 47% performance improvement. Signed-off-by: Bob Peterson Signed-off-by: Steven Whitehouse --- fs/gfs2/rgrp.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c index 0c5a575b513e..5232525934ae 100644 --- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -1401,9 +1401,14 @@ static void rg_mblk_search(struct gfs2_rgrpd *rgd, struct gfs2_inode *ip, u32 extlen; u32 free_blocks = rgd->rd_free_clone - rgd->rd_reserved; int ret; + struct inode *inode = &ip->i_inode; - extlen = max_t(u32, atomic_read(&rs->rs_sizehint), requested); - extlen = clamp(extlen, RGRP_RSRV_MINBLKS, free_blocks); + if (S_ISDIR(inode->i_mode)) + extlen = 1; + else { + extlen = max_t(u32, atomic_read(&rs->rs_sizehint), requested); + extlen = clamp(extlen, RGRP_RSRV_MINBLKS, free_blocks); + } if ((rgd->rd_free_clone < rgd->rd_reserved) || (free_blocks < extlen)) return; -- 2.20.1