diff options
Diffstat (limited to '0002-block-loop-avoiding-too-many-pending-per-work-I-O.patch')
| -rw-r--r-- | 0002-block-loop-avoiding-too-many-pending-per-work-I-O.patch | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/0002-block-loop-avoiding-too-many-pending-per-work-I-O.patch b/0002-block-loop-avoiding-too-many-pending-per-work-I-O.patch new file mode 100644 index 000000000000..c02a0b321641 --- /dev/null +++ b/0002-block-loop-avoiding-too-many-pending-per-work-I-O.patch @@ -0,0 +1,52 @@ +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 + |