Re: BUG: Unable to handle kernel paging request for data at address __percpu_counter_add

From: Raghavendra K T
Date: Mon Nov 30 2015 - 02:13:36 EST


On 11/24/2015 02:43 AM, Tejun Heo wrote:
Hello,

On Thu, Nov 19, 2015 at 03:54:35PM +0530, Raghavendra K T wrote:
While I was creating thousands of docker container on a power8 baremetal
(config: 4.3.0 kernel 1TB RAM, 20core (=160 cpu) system. After creating
around 5600 container
I have hit below problem.
[This is looking similar to
https://bugzilla.kernel.org/show_bug.cgi?id=101011, but
kernel had Revert "ext4: remove block_device_ejected" (bdfe0cbd746aa9) since
it is 4.3.0 tagged kernel]

Any hints on how to go about the fix. Please let me know if you think any
more information needed.

docker daemon is device mapper based. (and it took a day to recreate the
problem)

[ by disabling CONFIG_BLK_CGROUP and CONFIG_CGROUP_WRITEBACK I am able to
create 10k containers without any problem]

Could be the same problem that Ilya is trying to fix. ie. blkdev i_wb
pointing to a stale wb. Can you please see whether the following
patch resolves the issue?

http://lkml.kernel.org/g/1448054554-24138-1-git-send-email-idryomov@xxxxxxxxx


Hi Tejun,

Thanks again for the pointer. I was now able to create more than 10k
containers without any problem with CGROUP_WRITEBACK on whereas
earlier I had hit this problem few times around 5k+ containers itself.
(Also Replying to Ilya's thread).

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