Re: A mainline question about cgroup writeback

[zhong jiang]

On 2016/4/21 5:22, Tejun Heo wrote:
> On Tue, Apr 19, 2016 at 03:19:59PM +0800, zhong jiang wrote:
>> cgroup writeback support the filesystem both ext4 and ext2.
>> but,  it appears to be not work when I test the function in the ext4.
>> The example is as follows:
>> echo "8:0 1048576" > blkio.throttle.write_bps_device
>> echo $$ > cgroup.procs
>> dd if=/dev/zero of=/test.c bs=1M count=10240
>> 10240+0 records in
>> 10240+0 records out
>> 10737418240 bytes (11 GB) copied, 49.8796 s, 215 MB/s
> How much memory does the cgroup have available to it?  It's buffered
> write.  It might not get throttled if there are enough pages to dirty.
>
> Thanks.
>
  Maybe it's my fault.  I just limit two fields in dirty_background_bytes and dirty_bytes , 
  and I don't consider about  the available memory in the cgroup.


 Thanks
 zhongjiang