From df58f470ea4ca0ee9ea2a64cb2b556f7a4176034 Mon Sep 17 00:00:00 2001
From: "Thordur I. Bjornsson" <thib@cvs.openbsd.org>
Date: Mon, 10 Sep 2007 20:59:01 +0000
Subject: When selecting cylinder groups as candidates for new directory
 creation make sure that theres a minimum amount of free blocks in that
 cylinder group by tweaking the minbfree calculation. Without this, cylinder
 groups with no free blocks could be chosen which resaults in expensive
 searches for free blocks each time a new file is created in the directory.

Tweak the calculation of minifree (minimum free inodes) in the same
way. Also decrease the maxcontigdirs as the file system fills up to
lessen the chance of directory clusters overflowing the available
space in the cylinder group.

From FreeBSD (Rev 1.116 of sys/ufs/ffs/ffs_alloc.c);

ok miod@
---
 sys/ufs/ffs/ffs_alloc.c | 27 +++++++++------------------
 1 file changed, 9 insertions(+), 18 deletions(-)

(limited to 'sys/ufs')

diff --git a/sys/ufs/ffs/ffs_alloc.c b/sys/ufs/ffs/ffs_alloc.c
index c0fe153c52b..143a53e0ec1 100644
--- a/sys/ufs/ffs/ffs_alloc.c
+++ b/sys/ufs/ffs/ffs_alloc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ffs_alloc.c,v 1.78 2007/06/22 13:59:12 thib Exp $	*/
+/*	$OpenBSD: ffs_alloc.c,v 1.79 2007/09/10 20:59:00 thib Exp $	*/
 /*	$NetBSD: ffs_alloc.c,v 1.11 1996/05/11 18:27:09 mycroft Exp $	*/
 
 /*
@@ -926,7 +926,6 @@ ffs_dirpref(struct inode *pip)
 	avgifree = fs->fs_cstotal.cs_nifree / fs->fs_ncg;
 	avgbfree = fs->fs_cstotal.cs_nbfree / fs->fs_ncg;
 	avgndir = fs->fs_cstotal.cs_ndir / fs->fs_ncg;
-#if 1
 
 	/*
 	 * Force allocation in another cg if creating a first level dir.
@@ -953,33 +952,25 @@ ffs_dirpref(struct inode *pip)
 		goto end;
 	} else
 		prefcg = ino_to_cg(fs, pip->i_number);
-#else
-	prefcg = ino_to_cg(fs, pip->i_number);
-#endif
 
 	/*
 	 * Count various limits which used for
 	 * optimal allocation of a directory inode.
 	 */
-#if 1
 	maxndir = min(avgndir + fs->fs_ipg / 16, fs->fs_ipg);
-	minifree = avgifree - fs->fs_ipg / 4;
-	if (minifree < 0)
-		minifree = 0;
-	minbfree = avgbfree - fs->fs_fpg / fs->fs_frag / 4;
-	if (minbfree < 0)
-		minbfree = 0;
-#else
-	maxndir = avgndir + (fs->fs_ipg - avgndir) / 16;
-	minifree = avgifree * 3 / 4;
-	minbfree = avgbfree * 3 / 4;
-#endif
+	minifree = avgifree - (avgifree / 4);
+	if (minifree < 1)
+		minifree = 1;
+	minbfree = avgbfree - (avgbfree / 4);
+	if (minbfree < 1)
+		minbfree = 1;
+
 	cgsize = fs->fs_fsize * fs->fs_fpg;
 	dirsize = fs->fs_avgfilesize * fs->fs_avgfpdir;
 	curdirsize = avgndir ? (cgsize - avgbfree * fs->fs_bsize) / avgndir : 0;
 	if (dirsize < curdirsize)
 		dirsize = curdirsize;
-	maxcontigdirs = min(cgsize / dirsize, 255);
+	maxcontigdirs = min(avgbfree * fs->fs_bsize  / dirsize, 255);
 	if (fs->fs_avgfpdir > 0)
 		maxcontigdirs = min(maxcontigdirs,
 				    fs->fs_ipg / fs->fs_avgfpdir);
-- 
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