53 lines
1.8 KiB
Diff
53 lines
1.8 KiB
Diff
|
From 02a6b08b2706501fb0fe6ff2df2f7d8377f2f69b Mon Sep 17 00:00:00 2001
|
||
|
|
From: Ming Lei <ming.lei@canonical.com>
|
||
|
|
Date: Tue, 5 May 2015 19:49:55 +0800
|
||
|
|
Subject: [PATCH 2/2] block: loop: avoiding too many pending per work I/O
|
||
|
|
|
||
|
|
If there are too many pending per work I/O, too many
|
||
|
|
high priority work thread can be generated so that
|
||
|
|
system performance can be effected.
|
||
|
|
|
||
|
|
This patch limits the max_active parameter of workqueue as 16.
|
||
|
|
|
||
|
|
This patch fixes Fedora 22 live booting performance
|
||
|
|
regression when it is booted from squashfs over dm
|
||
|
|
based on loop, and looks the following reasons are
|
||
|
|
related with the problem:
|
||
|
|
|
||
|
|
- not like other filesyststems(such as ext4), squashfs
|
||
|
|
is a bit special, and I observed that increasing I/O jobs
|
||
|
|
to access file in squashfs only improve I/O performance a
|
||
|
|
little, but it can make big difference for ext4
|
||
|
|
|
||
|
|
- nested loop: both squashfs.img and ext3fs.img are mounted
|
||
|
|
as loop block, and ext3fs.img is inside the squashfs
|
||
|
|
|
||
|
|
- during booting, lots of tasks may run concurrently
|
||
|
|
|
||
|
|
Fixes: b5dd2f6047ca108001328aac0e8588edd15f1778
|
||
|
|
Cc: stable@vger.kernel.org (v4.0)
|
||
|
|
Cc: Justin M. Forbes <jforbes@fedoraproject.org>
|
||
|
|
Signed-off-by: Ming Lei <ming.lei@canonical.com>
|
||
|
|
Acked-by: Tejun Heo <tj@kernel.org>
|
||
|
|
Signed-off-by: Jens Axboe <axboe@fb.com>
|
||
|
|
---
|
||
|
|
drivers/block/loop.c | 2 +-
|
||
|
|
1 file changed, 1 insertion(+), 1 deletion(-)
|
||
|
|
|
||
|
|
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
|
||
|
|
index fec06d5..daaaf70 100644
|
||
|
|
--- a/drivers/block/loop.c
|
||
|
|
+++ b/drivers/block/loop.c
|
||
|
|
@@ -777,7 +777,7 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
|
||
|
|
goto out_putf;
|
||
|
|
error = -ENOMEM;
|
||
|
|
lo->wq = alloc_workqueue("kloopd%d",
|
||
|
|
- WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_UNBOUND, 0,
|
||
|
|
+ WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_UNBOUND, 16,
|
||
|
|
lo->lo_number);
|
||
|
|
if (!lo->wq)
|
||
|
|
goto out_putf;
|
||
|
|
--
|
||
|
|
2.4.5
|
||
|
|
|