From: Frederic Weisbecker <fweisbec@gmail.com>
To: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Alexey Dobriyan <adobriyan@gmail.com>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Christoph Lameter <cl@linux.com>
Subject: Re: 4.2.2: NR_CPUS effectively being 1 bug
Date: Sat, 3 Oct 2015 14:31:17 +0200 [thread overview]
Message-ID: <20151003123115.GA6389@lerouge> (raw)
In-Reply-To: <1443873884.3215.2.camel@gmail.com>
On Sat, Oct 03, 2015 at 02:04:44PM +0200, Mike Galbraith wrote:
> On Sat, 2015-10-03 at 10:52 +0200, Ingo Molnar wrote:
> > Ok, looks like a patch with good intentions but bad effects. Mind sending a revert
> > patch, changelogged, signed off?
>
> No. They know.
The reason for this patch is that NO_HZ_FULL is only useful on a CPU if no task
other than the desired one can be scheduled on it. Hence the cpu_isolated_map.
Only those who enable NO_HZ_FULL_ALL by accident do complain, not those who
really use it so far. At least it makes people realize their mistake.
That said I never liked that cpu_isolated_map. And some regular non-isolation
work may be needed to be done even on NO_HZ_FULL_ALL machines and it that
case we get screwed.
So I should revert that and defer that isolation work to explicit affinity
setting or cpusets.
next prev parent reply other threads:[~2015-10-03 12:31 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-02 20:46 4.2.2: NR_CPUS effectively being 1 bug Alexey Dobriyan
2015-10-02 21:00 ` Andrew Morton
2015-10-03 6:53 ` Peter Zijlstra
2015-10-03 7:38 ` Ingo Molnar
2015-10-03 8:15 ` Mike Galbraith
2015-10-03 8:18 ` Ingo Molnar
2015-10-03 8:24 ` Mike Galbraith
2015-10-03 8:52 ` Ingo Molnar
2015-10-03 12:04 ` Mike Galbraith
2015-10-03 12:31 ` Frederic Weisbecker [this message]
2015-10-03 12:49 ` Mike Galbraith
2015-10-03 12:14 ` Alexey Dobriyan
2015-10-03 12:19 ` Mike Galbraith
2015-10-03 6:50 ` Afzal Mohammed
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=20151003123115.GA6389@lerouge \
--to=fweisbec@gmail.com \
--cc=adobriyan@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=cl@linux.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=umgwanakikbuti@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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.