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From: Peter Zijlstra <peterz@infradead.org>
To: Florian Weimer <fweimer@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>,
	mingo@redhat.com, linux-kernel@vger.kernel.org,
	linux-api@vger.kernel.org
Subject: Re: [PATCH] sched/core: expand sched_getaffinity(2) to return number of CPUs
Date: Fri, 5 Apr 2019 13:04:15 +0200	[thread overview]
Message-ID: <20190405110415.GP12232@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <87wok83gfs.fsf@oldenburg2.str.redhat.com>

On Fri, Apr 05, 2019 at 12:16:39PM +0200, Florian Weimer wrote:

> > True; but I suppose glibc already does lots of that anyway, right? It
> > does contain the right information.
> 
> If I recall correctly my last investigation,
> /sys/devices/system/cpu/possible does not reflect the size of the
> affinity mask, either.

Strictly speaking correct; the bitmap can be longer than the highest
possible cpu number, however the remainder would be 0-padding and could
thus be stripped without issue.

So a bitmap sized to fit the max possible cpu number, should for all
practical purposes suffice.



  reply	other threads:[~2019-04-05 11:04 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-03 20:08 [PATCH] sched/core: expand sched_getaffinity(2) to return number of CPUs Alexey Dobriyan
2019-04-04  8:42 ` Peter Zijlstra
2019-04-04 18:02   ` Alexey Dobriyan
2019-04-05  9:26     ` Peter Zijlstra
2019-04-05 10:16   ` Florian Weimer
2019-04-05 11:04     ` Peter Zijlstra [this message]
2019-04-05 11:08       ` Florian Weimer
2019-04-05 11:49         ` Peter Zijlstra
2019-04-06 19:48     ` Alexey Dobriyan
2019-04-08  7:49       ` Florian Weimer

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