Re: [PATCH v4 2/4] writeback: support retrieving per group debug writeback stats of bdi

[Kemeng Shi <shikemeng@huaweicloud.com>]

on 4/23/2024 2:32 AM, Tejun Heo wrote:
> Hello,
> 
> On Tue, Apr 23, 2024 at 12:48:06AM +0800, Kemeng Shi wrote:
>> Add /sys/kernel/debug/bdi/xxx/wb_stats to show per group writeback stats
>> of bdi.
>>
>> Following domain hierarchy is tested:
>>                 global domain (320G)
>>                 /                 \
>>         cgroup domain1(10G)     cgroup domain2(10G)
>>                 |                 |
>> bdi            wb1               wb2
>>
>> /* per wb writeback info of bdi is collected */
>> cat /sys/kernel/debug/bdi/252:16/wb_stats
>> WbCgIno:                    1
>> WbWriteback:                0 kB
>> WbReclaimable:              0 kB
>> WbDirtyThresh:              0 kB
>> WbDirtied:                  0 kB
>> WbWritten:                  0 kB
>> WbWriteBandwidth:      102400 kBps
>> b_dirty:                    0
>> b_io:                       0
>> b_more_io:                  0
>> b_dirty_time:               0
>> state:                      1
>> WbCgIno:                 4094
>> WbWriteback:            54432 kB
>> WbReclaimable:         766080 kB
>> WbDirtyThresh:        3094760 kB
>> WbDirtied:            1656480 kB
>> WbWritten:             837088 kB
>> WbWriteBandwidth:      132772 kBps
>> b_dirty:                    1
>> b_io:                       1
>> b_more_io:                  0
>> b_dirty_time:               0
>> state:                      7
>> WbCgIno:                 4135
>> WbWriteback:            15232 kB
>> WbReclaimable:         786688 kB
>> WbDirtyThresh:        2909984 kB
>> WbDirtied:            1482656 kB
>> WbWritten:             681408 kB
>> WbWriteBandwidth:      124848 kBps
>> b_dirty:                    0
>> b_io:                       1
>> b_more_io:                  0
>> b_dirty_time:               0
>> state:                      7
>>
>> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
> 
> Maybe it'd be useful to delineate each wb better in the output? It's a bit
> difficult to parse visually. Other than that,
Sorry for this. A blank line was added at end of each wb in this patch but I
forgot to update the changelog.
As there is some kunit build problem reported, I will correct changelog with
the fix to build problem.
Thanks a lot for review.

Kemeng
> 
> Acked-by: Tejun Heo <tj@kernel.org>
> 
> Thanks.
>