Messages in this thread | | | Date | Wed, 25 Mar 2015 11:40:22 -0400 | From | Vivek Goyal <> | Subject | Re: [PATCHSET 1/3 v2 block/for-4.1/core] writeback: cgroup writeback support |
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On Mon, Mar 23, 2015 at 12:54:11AM -0400, Tejun Heo wrote: > > > How to test > ----------- > > * Boot with kernel option "cgroup__DEVEL__legacy_files_on_dfl". > > * umount /sys/fs/cgroup/memory > umount /sys/fs/cgroup/blkio > mkdir /sys/fs/cgroup/unified > mount -t cgroup -o __DEVEL__sane_behavior cgroup /sys/fs/cgroup/unified > echo +blkio > /sys/fs/cgroup/unified/cgroup.subtree_control > > * Build the cgroup hierarchy (don't forget to enable blkio using > subtree_control) and put processes in cgroups and run tests on ext2 > filesystems and blkio.throttle.* knobs. >
[..] > This patchset is on top of > > block/for-4.1/core bfd343aa1718 ("blk-mq: don't wait in blk_mq_queue_enter() if __GFP_WAIT isn't set") > + [1] [PATCH] writeback: fix possible underflow in write bandwidth calculation > > and available in the following git branch. > > git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-cgroup-writeback-20150322 >
Hi Tejun,
Great Work. I tried to do some basic testing and it seems to work.
I used "review-cgroup-writeback-switch-20150322" branch for my testing.
I have 32G of RAM on my system and I setup a write bandwidth of 1MB/s on the disk and allowed a dd to run. That dd quickly consumed 5G of page cache before it reached to a steady state. Sounds like too much of cache consumption which will be drained at a speed of 1MB/s. Not sure if this is expected or bdi back-pressure is not being applied soon enough.
Thanks Vivek
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