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[v3] EXT4: optimizing group search for inode allocation

Message ID 20151226084153.GA4248@server_lokesh.domain.name
State Not Applicable, archived
Headers show

Commit Message

lokesh jaliminche Dec. 26, 2015, 8:41 a.m. UTC 
From 5199982d29ff291b181c25af63a22d6f2d6d3f7b Mon Sep 17 00:00:00 2001
From: Lokesh Nagappa Jaliminche <lokesh.jaliminche@gmail.com>
Date: Sat, 26 Dec 2015 13:19:36 +0530
Subject: [PATCH v3] ext4: optimizing group search for inode allocation

Added a check at the start of group search loop to
avoid looping unecessarily in case of empty group.
This also allow group search to jump directly to
"found_flex_bg" with "stats" and "group" already set,
so there is no need to go through the extra steps of
setting "best_desc" and "best_group" and then break
out of the loop just to set "stats" and "group" again.

Signed-off-by: Lokesh Nagappa Jaliminche <lokesh.jaliminche@gmail.com>
---
 fs/ext4/ialloc.c |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)

                for (i = 0; i < ngroups; i++) {
                        g = (parent_group + i) % ngroups;
                        get_orlov_stats(sb, g, flex_size, &stats);
+                       /* the group can't get any better than empty */
+                       if (inodes_per_flex_group == stats.free_inodes &&
+                               clusters_per_flex_group == stats.free_clusters)
+                               goto found_flex_bg;
                        if (!stats.free_inodes)
                                continue;
                        if (stats.used_dirs >= best_ndir)
diff mbox

Patch

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index 1b8024d..16f94db 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -473,10 +473,14 @@  static int find_group_orlov(struct super_block *sb, struct inode *parent,
        ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);

        if (S_ISDIR(mode) &&
-           ((parent == d_inode(sb->s_root)) ||
-            (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
+               ((parent == d_inode(sb->s_root)) ||
+               (ext4_test_inode_flag(parent, EXT4_INODE_TOPDIR)))) {
+               unsigned int inodes_per_flex_group;
+               unsigned long int clusters_per_flex_group;
                int best_ndir = inodes_per_group;
                int ret = -1;
+               inodes_per_flex_group = inodes_per_group * flex_size;
+               clusters_per_flex_group = sbi->s_clusters_per_group * flex_size;
                if (qstr) {
                        hinfo.hash_version = DX_HASH_HALF_MD4;
@@ -489,6 +493,10 @@  static int find_group_orlov(struct super_block *sb, struct inode *parent,