From: Jan Kara <jack@suse.cz>
To: Ted Tso <tytso@mit.edu>
Cc: <linux-ext4@vger.kernel.org>,
Thorsten Leemhuis <regressions@leemhuis.info>,
Ojaswin Mujoo <ojaswin@linux.ibm.com>,
Stefan Wahren <stefan.wahren@i2se.com>,
Harshad Shirwadkar <harshadshirwadkar@gmail.com>,
Jan Kara <jack@suse.cz>,
stable@vger.kernel.org, Ritesh Harjani <ritesh.list@gmail.com>
Subject: [PATCH 1/5] ext4: Make mballoc try target group first even with mb_optimize_scan
Date: Thu, 8 Sep 2022 11:21:24 +0200 [thread overview]
Message-ID: <20220908092136.11770-1-jack@suse.cz> (raw)
In-Reply-To: <20220908091301.147-1-jack@suse.cz>
One of the side-effects of mb_optimize_scan was that the optimized
functions to select next group to try were called even before we tried
the goal group. As a result we no longer allocate files close to
corresponding inodes as well as we don't try to expand currently
allocated extent in the same group. This results in reaim regression
with workfile.disk workload of upto 8% with many clients on my test
machine:
baseline mb_optimize_scan
Hmean disk-1 2114.16 ( 0.00%) 2099.37 ( -0.70%)
Hmean disk-41 87794.43 ( 0.00%) 83787.47 * -4.56%*
Hmean disk-81 148170.73 ( 0.00%) 135527.05 * -8.53%*
Hmean disk-121 177506.11 ( 0.00%) 166284.93 * -6.32%*
Hmean disk-161 220951.51 ( 0.00%) 207563.39 * -6.06%*
Hmean disk-201 208722.74 ( 0.00%) 203235.59 ( -2.63%)
Hmean disk-241 222051.60 ( 0.00%) 217705.51 ( -1.96%)
Hmean disk-281 252244.17 ( 0.00%) 241132.72 * -4.41%*
Hmean disk-321 255844.84 ( 0.00%) 245412.84 * -4.08%*
Also this is causing huge regression (time increased by a factor of 5 or
so) when untarring archive with lots of small files on some eMMC storage
cards.
Fix the problem by making sure we try goal group first.
Fixes: 196e402adf2e ("ext4: improve cr 0 / cr 1 group scanning")
CC: stable@vger.kernel.org
Reported-and-tested-by: Stefan Wahren <stefan.wahren@i2se.com>
Tested-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Link: https://lore.kernel.org/all/20220727105123.ckwrhbilzrxqpt24@quack3/
Link: https://lore.kernel.org/all/0d81a7c2-46b7-6010-62a4-3e6cfc1628d6@i2se.com/
Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/ext4/mballoc.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index bd8f8b5c3d30..41e1cfecac3b 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1049,8 +1049,10 @@ static void ext4_mb_choose_next_group(struct ext4_allocation_context *ac,
{
*new_cr = ac->ac_criteria;
- if (!should_optimize_scan(ac) || ac->ac_groups_linear_remaining)
+ if (!should_optimize_scan(ac) || ac->ac_groups_linear_remaining) {
+ *group = next_linear_group(ac, *group, ngroups);
return;
+ }
if (*new_cr == 0) {
ext4_mb_choose_next_group_cr0(ac, new_cr, group, ngroups);
@@ -2636,7 +2638,7 @@ static noinline_for_stack int
ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
{
ext4_group_t prefetch_grp = 0, ngroups, group, i;
- int cr = -1;
+ int cr = -1, new_cr;
int err = 0, first_err = 0;
unsigned int nr = 0, prefetch_ios = 0;
struct ext4_sb_info *sbi;
@@ -2711,13 +2713,11 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
ac->ac_groups_linear_remaining = sbi->s_mb_max_linear_groups;
prefetch_grp = group;
- for (i = 0; i < ngroups; group = next_linear_group(ac, group, ngroups),
- i++) {
- int ret = 0, new_cr;
+ for (i = 0, new_cr = cr; i < ngroups; i++,
+ ext4_mb_choose_next_group(ac, &new_cr, &group, ngroups)) {
+ int ret = 0;
cond_resched();
-
- ext4_mb_choose_next_group(ac, &new_cr, &group, ngroups);
if (new_cr != cr) {
cr = new_cr;
goto repeat;
--
2.35.3
next prev parent reply other threads:[~2022-09-08 9:23 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-08 9:21 [PATCH 0/5 v3] ext4: Fix performance regression with mballoc Jan Kara
2022-09-08 9:21 ` Jan Kara [this message]
2022-09-22 2:52 ` [PATCH 1/5] ext4: Make mballoc try target group first even with mb_optimize_scan Theodore Ts'o
2022-09-22 9:15 ` Jan Kara
2022-09-26 9:11 ` Jan Kara
2022-09-26 17:32 ` Theodore Ts'o
2022-09-08 9:21 ` [PATCH 2/5] ext4: Avoid unnecessary spreading of allocations among groups Jan Kara
2022-09-08 9:21 ` [PATCH 3/5] ext4: Make directory inode spreading reflect flexbg size Jan Kara
2022-09-08 9:21 ` [PATCH 4/5] ext4: Use locality group preallocation for small closed files Jan Kara
2022-09-08 9:21 ` [PATCH 5/5] ext4: Use buckets for cr 1 block scan instead of rbtree Jan Kara
2022-09-09 6:12 ` Ritesh Harjani (IBM)
2022-09-08 10:36 ` [PATCH 0/5 v3] ext4: Fix performance regression with mballoc Stefan Wahren
2022-09-09 10:40 ` Jan Kara
2022-09-11 12:32 ` Stefan Wahren
-- strict thread matches above, loose matches on Subject: below --
2022-09-06 15:29 [PATCH 0/5 v2] " Jan Kara
2022-09-06 15:29 ` [PATCH 1/5] ext4: Make mballoc try target group first even with mb_optimize_scan Jan Kara
2022-09-07 17:43 ` Ritesh Harjani (IBM)
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220908092136.11770-1-jack@suse.cz \
--to=jack@suse.cz \
--cc=harshadshirwadkar@gmail.com \
--cc=linux-ext4@vger.kernel.org \
--cc=ojaswin@linux.ibm.com \
--cc=regressions@leemhuis.info \
--cc=ritesh.list@gmail.com \
--cc=stable@vger.kernel.org \
--cc=stefan.wahren@i2se.com \
--cc=tytso@mit.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.