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

From: Tejun Heo
Date: Mon Apr 22 2024 - 14:32:48 EST


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@xxxxxxxxxxxxxxx>

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@xxxxxxxxxx>

Thanks.

--
tejun