Re: [PATCH] pipe_read: don't wake up the writer if the pipe is still full

[K Prateek Nayak]

Hello Mateusz,

On 3/4/2025 12:02 AM, K Prateek Nayak wrote:
> Hello Mateusz,
>
> On 3/3/2025 11:24 PM, Mateusz Guzik wrote:
> > Can you guys try out the patch below?
> >
> > It changes things up so that there is no need to read 2 different vars.
> >
> > It is not the final version and I don't claim to be able to fully
> > justify the thing at the moment either, but I would like to know if it
> > fixes the problem.
>
> Happy to help! We've queued the below patch for an overnight run, will
> report back once it is done.

Hackbench has been running for a few thousand iteration now without
experiencing any hangs yet with your changes.

> Full disclaimer: We're testing on top of commit aaec5a95d596
> ("pipe_read: don't wake up the writer if the pipe is still full") where the
> issue is more reproducible. I've replaced the VFS_BUG_ON() with a plain
> BUG_ON() based on [1] since v6.14-rc1 did not include the CONFIG_DEBUG_VFS
> bits. Hope that is alright.
>
> [1] https://lore.kernel.org/lkml/20250209185523.745956-2-mjguzik@xxxxxxxxx/
>
> /off to get some shut eyes/

--
Thanks and Regards,
Prateek