This commit is contained in:
Dan Ziemba 2015-07-02 23:40:34 -04:00
parent 8ba39a7187
commit e2d4c7a106
3 changed files with 195 additions and 1 deletions

View File

@ -0,0 +1,133 @@
From ebcacf05168d9791d39c5434164c64b9ef937171 Mon Sep 17 00:00:00 2001
From: Ming Lei <ming.lei@canonical.com>
Date: Tue, 5 May 2015 19:49:54 +0800
Subject: [PATCH 1/2] block: loop: convert to per-device workqueue
Documentation/workqueue.txt:
If there is dependency among multiple work items used
during memory reclaim, they should be queued to separate
wq each with WQ_MEM_RECLAIM.
Loop devices can be stacked, so we have to convert to per-device
workqueue. One example is Fedora live CD.
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 | 30 ++++++++++++++----------------
drivers/block/loop.h | 1 +
2 files changed, 15 insertions(+), 16 deletions(-)
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index d1f168b..fec06d5 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -85,8 +85,6 @@ static DEFINE_MUTEX(loop_index_mutex);
static int max_part;
static int part_shift;
-static struct workqueue_struct *loop_wq;
-
/*
* Transfer functions
*/
@@ -777,6 +775,12 @@ static int loop_set_fd(struct loop_device *lo, fmode_t mode,
size = get_loop_size(lo, file);
if ((loff_t)(sector_t)size != size)
goto out_putf;
+ error = -ENOMEM;
+ lo->wq = alloc_workqueue("kloopd%d",
+ WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_UNBOUND, 0,
+ lo->lo_number);
+ if (!lo->wq)
+ goto out_putf;
error = 0;
@@ -924,6 +928,8 @@ static int loop_clr_fd(struct loop_device *lo)
lo->lo_flags = 0;
if (!part_shift)
lo->lo_disk->flags |= GENHD_FL_NO_PART_SCAN;
+ destroy_workqueue(lo->wq);
+ lo->wq = NULL;
mutex_unlock(&lo->lo_ctl_mutex);
/*
* Need not hold lo_ctl_mutex to fput backing file.
@@ -1477,9 +1483,13 @@ static int loop_queue_rq(struct blk_mq_hw_ctx *hctx,
const struct blk_mq_queue_data *bd)
{
struct loop_cmd *cmd = blk_mq_rq_to_pdu(bd->rq);
+ struct loop_device *lo = cmd->rq->q->queuedata;
blk_mq_start_request(bd->rq);
+ if (lo->lo_state != Lo_bound)
+ return -EIO;
+
if (cmd->rq->cmd_flags & REQ_WRITE) {
struct loop_device *lo = cmd->rq->q->queuedata;
bool need_sched = true;
@@ -1493,9 +1503,9 @@ static int loop_queue_rq(struct blk_mq_hw_ctx *hctx,
spin_unlock_irq(&lo->lo_lock);
if (need_sched)
- queue_work(loop_wq, &lo->write_work);
+ queue_work(lo->wq, &lo->write_work);
} else {
- queue_work(loop_wq, &cmd->read_work);
+ queue_work(lo->wq, &cmd->read_work);
}
return BLK_MQ_RQ_QUEUE_OK;
@@ -1507,9 +1517,6 @@ static void loop_handle_cmd(struct loop_cmd *cmd)
struct loop_device *lo = cmd->rq->q->queuedata;
int ret = -EIO;
- if (lo->lo_state != Lo_bound)
- goto failed;
-
if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY))
goto failed;
@@ -1858,13 +1865,6 @@ static int __init loop_init(void)
goto misc_out;
}
- loop_wq = alloc_workqueue("kloopd",
- WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_UNBOUND, 0);
- if (!loop_wq) {
- err = -ENOMEM;
- goto misc_out;
- }
-
blk_register_region(MKDEV(LOOP_MAJOR, 0), range,
THIS_MODULE, loop_probe, NULL, NULL);
@@ -1902,8 +1902,6 @@ static void __exit loop_exit(void)
blk_unregister_region(MKDEV(LOOP_MAJOR, 0), range);
unregister_blkdev(LOOP_MAJOR, "loop");
- destroy_workqueue(loop_wq);
-
misc_deregister(&loop_misc);
}
diff --git a/drivers/block/loop.h b/drivers/block/loop.h
index 301c27f..49564ed 100644
--- a/drivers/block/loop.h
+++ b/drivers/block/loop.h
@@ -54,6 +54,7 @@ struct loop_device {
gfp_t old_gfp_mask;
spinlock_t lo_lock;
+ struct workqueue_struct *wq;
struct list_head write_cmd_head;
struct work_struct write_work;
bool write_started;
--
2.4.5

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@ -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

View File

@ -3,7 +3,7 @@
pkgbase=linux-vfio
_srcname=linux-4.0
pkgver=4.0.7
pkgrel=1
pkgrel=2
arch=('i686' 'x86_64')
url="http://www.kernel.org/"
license=('GPL2')
@ -17,6 +17,8 @@ source=("https://www.kernel.org/pub/linux/kernel/v4.x/${_srcname}.tar.xz"
'config' 'config.x86_64'
# standard config files for mkinitcpio ramdisk
'linux.preset'
'0001-block-loop-convert-to-per-device-workqueue.patch'
'0002-block-loop-avoiding-too-many-pending-per-work-I-O.patch'
'change-default-console-loglevel.patch'
'override_for_missing_acs_capabilities.patch'
'i915_317.patch'
@ -28,6 +30,8 @@ sha256sums=('0f2f7d44979bc8f71c4fc5d3308c03499c26a824dd311fdf6eef4dee0d7d5991'
'e8d639582697f22333a96aa1614bcf5d9bcf2e6683a3d5296f9cfc64843606f1'
'5dadd75693e512b77f87f5620e470405b943373613eaf4df561037e9296453be'
'f0d90e756f14533ee67afda280500511a62465b4f76adcc5effa95a40045179c'
'0682df710e8d23f0d420b3b01fbfe409b3911940b1a379b78d9f4a5ac8590386'
'af42b1456caee0b0db8f3cc770c78083b40159260b99db4930e503ac7824eacc'
'1256b241cd477b265a3c2d64bdc19ffe3c9bbcee82ea3994c590c2c76e767d99'
'975f79348119bfba8dd972a9fbfe6b38484c45bfd228f2f6d48a0c02426ba149'
'f86ce528b63f198b84c4d8d92d35329aa4000d462217dc2db03bac5eb693cf19')
@ -49,6 +53,11 @@ prepare() {
# add latest fixes from stable queue, if needed
# http://git.kernel.org/?p=linux/kernel/git/stable/stable-queue.git
# Fix deadlock with stacked loop devices (FS#45129)
# http://marc.info/?l=linux-kernel&m=143280649731902&w=2
patch -Np1 -i ../0001-block-loop-convert-to-per-device-workqueue.patch
patch -Np1 -i ../0002-block-loop-avoiding-too-many-pending-per-work-I-O.patch
# set DEFAULT_CONSOLE_LOGLEVEL to 4 (same value as the 'quiet' kernel param)
# remove this when a Kconfig knob is made available by upstream
# (relevant patch sent upstream: https://lkml.org/lkml/2011/7/26/227)