Re: [PATCH -next v2 0/7] limit the number of plugged bio

From: Yu Kuai
Date: Fri May 12 2023 - 22:04:10 EST


在 2023/05/13 8:50, Song Liu 写道:
On Fri, May 12, 2023 at 2:43 AM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:


在 2023/04/26 16:20, Yu Kuai 写道:
From: Yu Kuai <yukuai3@xxxxxxxxxx>

Changes in v2:
- remove the patch to rename raid1-10.c

This patchset tries to limit the number of plugged bio for raid1 and
raid10, which is done in the last patch, other patches are some refactor
and optimizations.

This patchset is tested with a new test [1], this test triggers dirty
pages writeback for 10s, and in the meantime checks disk inflight.

Before this patchset, test will fail because inflight exceed threshold
(threshold is set to 4096 in the test, in theory this can be mutch
greater as long as there are enough dirty pages and memory).

After this patchset, inflight is within 96 (MAX_PLUG_BIO * copies).


Friendly ping...

I am sorry for the delay.

The set looks good overall, but I will need some more time to take a closer
look. A few comments/questions:

1. For functions in raid1-10.c, let's prefix them with raid1_ instead of md_*.
Ok, I'll change that in v3.

2. Do we need unplug_wq to be per-bitmap? Would a shared queue work?

I think this can work, the limitation is that global workqueue can
support 256 queued work at a time, but this should be enough.