Date: Tue, 8 Sep 2009 15:19:41 -0400
From: Vivek Goyal <vgoyal@redhat.com>
To: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Cc: linux-kernel@vger.kernel.org, jens.axboe@oracle.com,
       containers@lists.linux-foundation.org, dm-devel@redhat.com,
       nauman@google.com, dpshah@google.com, lizf@cn.fujitsu.com,
       mikew@google.com, fchecconi@gmail.com, paolo.valente@unimore.it,
       ryov@valinux.co.jp, fernando@oss.ntt.co.jp, s-uchida@ap.jp.nec.com,
       taka@valinux.co.jp, jmoyer@redhat.com, dhaval@linux.vnet.ibm.com,
       balbir@linux.vnet.ibm.com, righi.andrea@gmail.com,
       m-ikeda@ds.jp.nec.com, agk@redhat.com, akpm@linux-foundation.org,
       peterz@infradead.org, jmarchan@redhat.com,
       torvalds@linux-foundation.org, mingo@elte.hu, riel@redhat.com
Subject: Re: [RFC] IO scheduler based IO controller V9
Message-ID: <20090908191941.GF15974@redhat.com>
References: <1251495072-7780-1-git-send-email-vgoyal@redhat.com> <4AA4B905.8010801@cn.fujitsu.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <4AA4B905.8010801@cn.fujitsu.com>
User-Agent: Mutt/1.5.18 (2008-05-17)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 2620
Lines: 103

On Mon, Sep 07, 2009 at 03:40:53PM +0800, Gui Jianfeng wrote:
> Hi Vivek,
> 
> I happened to encount a bug when i test IO Controller V9.
> When there are three tasks to run concurrently in three group,
> that is, one is parent group, and other two tasks are running 
> in two different child groups respectively to read or write 
> files in some disk, say disk "hdb", The task may hang up, and 
> other tasks which access into "hdb" will also hang up.
> 
> The bug only happens when using AS io scheduler.
> The following scirpt can reproduce this bug in my box.
> 

Hi Gui,

I tried reproducing this on my system and can't reproduce it. All the
three processes get killed and system does not hang.

Can you please dig deeper a bit into it. 

- If whole system hangs or it is just IO to disk seems to be hung.
- Does io scheduler switch on the device work
- If the system is not hung, can you capture the blktrace on the device.
  Trace might give some idea, what's happening.

Thanks
Vivek
 
> ===========
> #!/bin/sh
> 
> mkdir /cgroup
> mount -t cgroup -o io,blkio io  /cgroup
> 
> echo anticipatory > /sys/block/hdb/queue/scheduler
> 
> mkdir /cgroup/test1
> echo 100 > /cgroup/test1/io.weight
> 
> mkdir /cgroup/test2
> echo 400 > /cgroup/test2/io.weight
> 
> mkdir /cgroup/test2/test3
> echo 400 > /cgroup/test2/test3/io.weight
> 
> mkdir /cgroup/test2/test4
> echo 400 > /cgroup/test2/test4/io.weight
> 
> #./rwio -r -f /hdb2/2000M.3 &
> dd if=/hdb2/2000M.3 of=/dev/null &
> pid4=$!
> echo $pid4 > /cgroup/test2/test3/tasks
> echo "pid4: $pid4"
> 
> #./rwio -r -f /hdb2/2000M.1 &
> dd if=/hdb2/2000M.1 of=/dev/null &
> pid1=$!
> echo $pid1 > /cgroup/test1/tasks
> echo "pid1 $pid1"
> 
> #./rwio -r -f /hdb2/2000M.2 &
> dd if=/hdb2/2000M.2 of=/dev/null &
> pid2=$!
> echo $pid2 > /cgroup/test2/test4/tasks
> echo "pid2 $pid2"
> 
> sleep 20
> 
> for ((;1;))
> {
>         ps -p $pid1 > /dev/null 2>&1
>         if [ $? -ne 0 ]; then
>                 break
>         fi
> 
>         kill -9 $pid1 > /dev/null 2>&1
> }
> for ((;1;))
> {
>         ps -p $pid2 > /dev/null 2>&1
>         if [ $? -ne 0 ]; then
>                 break
>         fi
> 
>         kill -9 $pid2 > /dev/null 2>&1
> }
> 
> 
> kill -9 $pid4 > /dev/null 2>&1
> 
> rmdir /cgroup/test2/test3
> rmdir /cgroup/test2/test4
> rmdir /cgroup/test2
> rmdir /cgroup/test1
> 
> umount /cgroup
> rmdir /cgroup
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/