lkml.org 
[lkml]   [2023]   [May]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH 0/8] vhost_tasks: Use CLONE_THREAD/SIGHAND
On Thu, May 18, 2023 at 10:25:11AM +0200, Christian Brauner wrote:
> On Wed, May 17, 2023 at 07:09:12PM -0500, Mike Christie wrote:
> > This patch allows the vhost and vhost_task code to use CLONE_THREAD,
> > CLONE_SIGHAND and CLONE_FILES. It's a RFC because I didn't do all the
> > normal testing, haven't coverted vsock and vdpa, and I know you guys
> > will not like the first patch. However, I think it better shows what
>
> Just to summarize the core idea behind my proposal is that no signal
> handling changes are needed unless there's a bug in the current way
> io_uring workers already work. All that should be needed is
> s/PF_IO_WORKER/PF_USER_WORKER/ in signal.c.
>
> If you follow my proposal than vhost and io_uring workers should almost
> collapse into the same concept. Specifically, io_uring workers and vhost
> workers should behave the same when it comes ot handling signals.
>
> See
> https://lore.kernel.org/lkml/20230518-kontakt-geduckt-25bab595f503@brauner
>
>
> > we need from the signal code and how we can support signals in the
> > vhost_task layer.
> >
> > Note that I took the super simple route and kicked off some work to
> > the system workqueue. We can do more invassive approaches:
> > 1. Modify the vhost drivers so they can check for IO completions using
> > a non-blocking interface. We then don't need to run from the system
> > workqueue and can run from the vhost_task.
> >
> > 2. We could drop patch 1 and just say we are doing a polling type
> > of approach. We then modify the vhost layer similar to #1 where we
> > can check for completions using a non-blocking interface and use
> > the vhost_task task.
>
> My preference would be to do whatever is the minimal thing now and has
> the least bug potential and is the easiest to review for us non-vhost
> experts. Then you can take all the time to rework and improve the vhost
> infra based on the possibilities that using user workers offers. Plus,
> that can easily happen in the next kernel cycle.
>
> Remember, that we're trying to fix a regression here. A regression on an
> unreleased kernel but still.

It's a public holiday here today so I'll try to find time to review this
tomorrow.

\
 
 \ /
  Last update: 2023-05-18 10:41    [W:0.268 / U:0.876 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site