On Wed, 18 Jun 2008 00:34:16 +0900, KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> wrote:
> > > I got this bug while migrating pages only a few times
> > > via memory_migrate of cpuset.
> > > 
> > > Unfortunately, even if this patch is applied,
> > > I got bad_page problem after hundreds times of page migration
> > > (I'll report it in another mail).
> > > But I believe something like this patch is needed anyway.
> > > 
> > 
> > I got bad_page after hundreds times of page migration.
> > It seems that a locked page is being freed.
> 
> I can't reproduce this bad page.
> I'll try again tomorrow ;)
> 

OK. I'll report on my test more precisely.

- Environment
  HW: 4CPU(x86_64), 2node NUMA
  kernel: 2.6.26-rc5-mm3 + Lee's two fixes about double unlock_page
          + my patch. config is attached.

- mount cpuset and make settings
  # mount -t cgroup -o cpuset cpuset /cgroup/cpuset

  # mkdir /cgroup/cpuset/01
  # echo 0-1 >/cgroup/cpuset/01/cpuset.cpus
  # echo 0 >/cgroup/cpuset/01/cpuset.mems
  # echo 1 >/cgroup/cpuset/01/cpuset.memory_migrate

  # mkdir /cgroup/cpuset/02
  # echo 2-3 >/cgroup/cpuset/02/cpuset.cpus
  # echo 1 >/cgroup/cpuset/02/cpuset.mems
  # echo 1 >/cgroup/cpuset/02/cpuset.memory_migrate

- register processes in cpusets
  # echo $$ >/cgroup/cpuset/01/tasks

  I'm using LTP's page01 test, and running two instances infinitely.
  # while true; do (somewhere)/page01 4194304 1; done &
  # while true; do (somewhere)/page01 4194304 1; done &

  The same thing should be done about 02 directory.

- echo pids to another directory
  Run simple script like below.

---
#!/bin/bash

G1=$1
G2=$2

move_task()
{
        for pid in $1
        do
                echo $pid >$2/tasks 2>/dev/null
        done
}

G1_TASK=`cat ${G1}/tasks`
G2_TASK=`cat ${G2}/tasks`

move_task "${G1_TASK}" ${G2} &
move_task "${G2_TASK}" ${G1} &

wait
---

Please let me know if you need other information.
I'm also digging this problem.


Thanks,
Daisuke Nishimura.