On Tue, Apr 21, 2009 at 8:04 PM, Gui Jianfeng <guijianfeng@xxxxxxxxxxxxxx> wrote: > Vivek Goyal wrote: >> On Fri, Apr 10, 2009 at 05:33:10PM +0800, Gui Jianfeng wrote: >>> Vivek Goyal wrote: >>>> Hi All, >>>> >>>> Here is another posting for IO controller patches. Last time I had posted >>>> RFC patches for an IO controller which did bio control per cgroup. >>> Hi Vivek, >>> >>> I got the following OOPS when testing, can't reproduce again :( >>> >> >> Hi Gui, >> >> Thanks for the report. Will look into it and see if I can reproduce it. > > Hi Vivek, > > The following script can reproduce the bug in my box. > > #!/bin/sh > > mkdir /cgroup > mount -t cgroup -o io io /cgroup > mkdir /cgroup/test1 > mkdir /cgroup/test2 > > echo cfq > /sys/block/sda/queue/scheduler > echo 7 > /cgroup/test1/io.ioprio > echo 1 > /cgroup/test2/io.ioprio > echo 1 > /proc/sys/vm/drop_caches > dd if=1000M.1 of=/dev/null & > pid1=$! > echo $pid1 > echo $pid1 > /cgroup/test1/tasks > dd if=1000M.2 of=/dev/null > pid2=$! > echo $pid2 > echo $pid2 > /cgroup/test2/tasks > > > rmdir /cgroup/test1 > rmdir /cgroup/test2 > umount /cgroup > rmdir /cgroup Yes, this bug happens when we move a task from a cgroup to another one, and delete the cgroup. Since the actual move to the new cgroup is performed in a delayed fashion, if the cgroup is removed before another request from the task is seen (and the actual move is performed) , it results in a hit on BUG_ON. I am working on a patch that will solve this problem and a few others; basically it would do ref counting for io_group structure. I am having a few problems with it at the moment; will post the patch as soon as I can get it to work. > > -- > Regards > Gui Jianfeng > > > > _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
