Hi all,
On Mon, 17 Jun 2019 16:06:35 +1000 Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> wrote:
>
> Today's linux-next merge of the cgroup tree got a conflict in:
>
> Documentation/cgroup-v1/blkio-controller.rst
>
> between commit:
>
> fb5772cbfe48 ("blkio-controller.txt: Remove references to CFQ")
>
> from Linus' tree and commit:
>
> 99c8b231ae6c ("docs: cgroup-v1: convert docs to ReST and rename to *.rst")
>
> from the cgroup tree.
>
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging. You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
>
> --
> Cheers,
> Stephen Rothwell
>
> diff --cc Documentation/cgroup-v1/blkio-controller.rst
> index d1a1b7bdd03a,2c1b907afc14..000000000000
> --- a/Documentation/cgroup-v1/blkio-controller.rst
> +++ b/Documentation/cgroup-v1/blkio-controller.rst
> @@@ -15,15 -19,71 +17,18 @@@ level logical devices like device mappe
>
> HOWTO
> =====
> -Proportional Weight division of bandwidth
> ------------------------------------------
> -You can do a very simple testing of running two dd threads in two different
> -cgroups. Here is what you can do.
> -
> -- Enable Block IO controller::
> -
> - CONFIG_BLK_CGROUP=y
> -
> -- Enable group scheduling in CFQ:
> -
> -
> - CONFIG_CFQ_GROUP_IOSCHED=y
> -
> -- Compile and boot into kernel and mount IO controller (blkio); see
> - cgroups.txt, Why are cgroups needed?.
> -
> - ::
> -
> - mount -t tmpfs cgroup_root /sys/fs/cgroup
> - mkdir /sys/fs/cgroup/blkio
> - mount -t cgroup -o blkio none /sys/fs/cgroup/blkio
> -
> -- Create two cgroups::
> -
> - mkdir -p /sys/fs/cgroup/blkio/test1/ /sys/fs/cgroup/blkio/test2
> -
> -- Set weights of group test1 and test2::
> -
> - echo 1000 > /sys/fs/cgroup/blkio/test1/blkio.weight
> - echo 500 > /sys/fs/cgroup/blkio/test2/blkio.weight
> -
> -- Create two same size files (say 512MB each) on same disk (file1, file2) and
> - launch two dd threads in different cgroup to read those files::
> -
> - sync
> - echo 3 > /proc/sys/vm/drop_caches
> -
> - dd if=/mnt/sdb/zerofile1 of=/dev/null &
> - echo $! > /sys/fs/cgroup/blkio/test1/tasks
> - cat /sys/fs/cgroup/blkio/test1/tasks
> -
> - dd if=/mnt/sdb/zerofile2 of=/dev/null &
> - echo $! > /sys/fs/cgroup/blkio/test2/tasks
> - cat /sys/fs/cgroup/blkio/test2/tasks
> -
> -- At macro level, first dd should finish first. To get more precise data, keep
> - on looking at (with the help of script), at blkio.disk_time and
> - blkio.disk_sectors files of both test1 and test2 groups. This will tell how
> - much disk time (in milliseconds), each group got and how many sectors each
> - group dispatched to the disk. We provide fairness in terms of disk time, so
> - ideally io.disk_time of cgroups should be in proportion to the weight.
> -
> Throttling/Upper Limit policy
> -----------------------------
> - - Enable Block IO controller
> + - Enable Block IO controller::
> +
> CONFIG_BLK_CGROUP=y
>
> - - Enable throttling in block layer
> + - Enable throttling in block layer::
> +
> CONFIG_BLK_DEV_THROTTLING=y
>
> - - Mount blkio controller (see cgroups.txt, Why are cgroups needed?)
> + - Mount blkio controller (see cgroups.txt, Why are cgroups needed?)::
> +
> mount -t cgroup -o blkio none /sys/fs/cgroup/blkio
>
> - Specify a bandwidth rate on particular device for root group. The format
I am still getting this conflict (the commit ids may have changed).
Just a reminder in case you think Linus may need to know.
--
Cheers,
Stephen Rothwell
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