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Message-ID: <20151226084153.GA4248@server_lokesh.domain.name>
Date: Sat, 26 Dec 2015 14:11:53 +0530
From: Lokesh Jaliminche <lokesh.jaliminche@...il.com>
To: Andreas Dilger <adilger@...ger.ca>, tytso@....edu
Cc: linux-ext4@...r.kernel.org
Subject: Re: [PATCH v3] EXT4: optimizing group search for inode allocation
>From 5199982d29ff291b181c25af63a22d6f2d6d3f7b Mon Sep 17 00:00:00 2001
From: Lokesh Nagappa Jaliminche <lokesh.jaliminche@...il.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@...il.com>
---
fs/ext4/ialloc.c | 12 ++++++++++--
1 files changed, 10 insertions(+), 2 deletions(-)
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,
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)
--
1.7.1
On Mon, Dec 21, 2015 at 10:27:37AM -0700, Andreas Dilger wrote:
> On Dec 18, 2015, at 4:32 PM, lokesh jaliminche <lokesh.jaliminche@...il.com> wrote:
> >
> > From 9e09fef78b2fa552c883bf8124af873abfde0805 Mon Sep 17 00:00:00 2001
> > From: Lokesh Nagappa Jaliminche <lokesh.jaliminche@...gate.com>
>
> In the patch summary there is a typo - s/serch/search/
>
> Also, it appears your email client has mangled the whitespace in the
> patch. Please use "git send-email" to send your patch to the list:
>
> git send-email --to tytso@....edu --cc linux-ext4@...r.kernel.org HEAD~1
>
> so that it arrives intact. You probably need to set it up in ~/.gitconfig:
>
> [sendemail]
> confirm = compose
> smtpdomain = {your client hostname}
> smtpserver = {your SMTP server hostname}
>
> Cheers, Andreas
>
> > 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 N Jaliminche <lokesh.jaliminche@...il.com>
> > ---
> > fs/ext4/ialloc.c | 8 ++++++++
> > 1 files changed, 8 insertions(+), 0 deletions(-)
> >
> > diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
> > index 1b8024d..588bf8e 100644
> > --- a/fs/ext4/ialloc.c
> > +++ b/fs/ext4/ialloc.c
> > @@ -446,6 +446,8 @@ static int find_group_orlov(struct super_block
> > *sb, struct inode *parent,
> > struct ext4_sb_info *sbi = EXT4_SB(sb);
> > ext4_group_t real_ngroups = ext4_get_groups_count(sb);
> > int inodes_per_group = EXT4_INODES_PER_GROUP(sb);
> > + unsigned int inodes_per_flex_group;
> > + long unsigned int blocks_per_clustre;
> > unsigned int freei, avefreei, grp_free;
> > ext4_fsblk_t freeb, avefreec;
> > unsigned int ndirs;
> > @@ -470,6 +472,8 @@ static int find_group_orlov(struct super_block
> > *sb, struct inode *parent,
> > percpu_counter_read_positive(&sbi->s_freeclusters_counter));
> > avefreec = freeb;
> > do_div(avefreec, ngroups);
> > + inodes_per_flex_group = inodes_per_group * flex_size;
> > + blocks_per_clustre = sbi->s_blocks_per_group * flex_size;
> > ndirs = percpu_counter_read_positive(&sbi->s_dirs_counter);
> >
> > if (S_ISDIR(mode) &&
> > @@ -489,6 +493,10 @@ static int find_group_orlov(struct super_block
> > *sb, struct inode *parent,
> > 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 &&
> > + blocks_per_clustre == stats.free_clusters)
> > + goto found_flex_bg;
> > if (!stats.free_inodes)
> > continue;
> > if (stats.used_dirs >= best_ndir)
> > --
> > 1.7.1
> > <0001-EXT4-optimizing-group-serch-for-inode-allocation.patch>
>
>
> Cheers, Andreas
>
>
>
>
>
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