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

[Tejun Heo <tj@kernel.org>]

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,

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

Thanks.

-- 
tejun