From: Peter Zijlstra <peterz@infradead.org>
To: Josh Don <joshdon@google.com>
Cc: Ankit Jain <ankitja@vmware.com>,
yury.norov@gmail.com, andriy.shevchenko@linux.intel.com,
linux@rasmusvillemoes.dk, qyousef@layalina.io, pjt@google.com,
bristot@redhat.com, vschneid@redhat.com,
linux-kernel@vger.kernel.org, namit@vmware.com,
amakhalov@vmware.com, srinidhir@vmware.com,
vsirnapalli@vmware.com, vbrahmajosyula@vmware.com,
akaher@vmware.com, srivatsa@csail.mit.edu
Subject: Re: [PATCH RFC] cpumask: Randomly distribute the tasks within affinity mask
Date: Thu, 12 Oct 2023 10:05:46 +0200 [thread overview]
Message-ID: <20231012080546.GI6307@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <CABk29NvHx2saNLdYmQgt31R8W28p7=GUtXiiupgE5czXRBAx5g@mail.gmail.com>
On Wed, Oct 11, 2023 at 04:55:35PM -0700, Josh Don wrote:
> Hey Peter,
>
> > +static struct cpumask *root_domain_allowed(struct cpumask *newmask,
> > + struct cpumask *scratch,
> > + struct cpumask *valid)
> > +{
> > + struct root_domain *rd;
> > + struct cpumask *mask;
> > + struct rq *rq;
> > +
> > + int first = cpumask_first_and(newmask, valid);
> > + if (first >= nr_cpu_ids)
> > + return NULL;
>
> This picks the first arbitrarily, but isn't it possible for the mask
> to span both isolated and non-isolated cpus? In which case, the rest
> of this just boils down to chance (ie. whatever the span happens to be
> for the first cpu here)?
Yes, but it matches historical behaviour :/
Like I said, ideally we'd flat out reject masks like this, but...
next prev parent reply other threads:[~2023-10-12 8:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-11 7:19 Ankit Jain
2023-10-11 10:39 ` Andy Shevchenko
2023-10-11 10:53 ` Peter Zijlstra
2023-10-11 11:46 ` Peter Zijlstra
2023-10-11 13:52 ` Peter Zijlstra
2023-10-11 23:55 ` Josh Don
2023-10-12 8:05 ` Peter Zijlstra [this message]
2023-10-12 15:43 ` Ankit Jain
2023-10-12 0:16 ` Yury Norov
2023-10-12 15:52 ` Ankit Jain
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20231012080546.GI6307@noisy.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=akaher@vmware.com \
--cc=amakhalov@vmware.com \
--cc=andriy.shevchenko@linux.intel.com \
--cc=ankitja@vmware.com \
--cc=bristot@redhat.com \
--cc=joshdon@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux@rasmusvillemoes.dk \
--cc=namit@vmware.com \
--cc=pjt@google.com \
--cc=qyousef@layalina.io \
--cc=srinidhir@vmware.com \
--cc=srivatsa@csail.mit.edu \
--cc=vbrahmajosyula@vmware.com \
--cc=vschneid@redhat.com \
--cc=vsirnapalli@vmware.com \
--cc=yury.norov@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Powered by JetHome