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

[Yu Kuai]

Hi,

在 2023/05/13 8:50, Song Liu 写道:
> On Fri, May 12, 2023 at 2:43 AM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:
> > Hi,
> >
> > 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).
> > >
> > > [1] https://lore.kernel.org/linux-raid/20230426073447.1294916-1-yukuai1@xxxxxxxxxxxxxxx/
> >
> > 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.

Thanks,
Kuai
> Thanks,
> Song
> .