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From: Rusty Russell <rusty@rustcorp.com.au>
To: npollitt@engr.sgi.com
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Process pinning
Date: Wed, 11 Apr 2001 21:05:47 +1000	[thread overview]
Message-ID: <m14nIRX-001RovC@mozart> (raw)
In-Reply-To: Your message of "Mon, 09 Apr 2001 17:08:23 MST." <20010409170823.C2316@engr.sgi.com>

In message <20010409170823.C2316@engr.sgi.com> you write:
> Changes to array.c expose cpus_allowed in proc/pid/stat.  

Call me old fashioned, but I prefer my bitmasks in hex.

Please also consider changing:

still_running:
	c = goodness(prev, this_cpu, prev->active_mm);
	next = prev;

to:

still_running:
	if (prev & (1 << this_cpu)) {
		c = goodness(prev, this_cpu, prev->active_mm);
		next = prev;
	}

Otherwise, you will keep scheduling a RT process forever on a
disallowed CPU on which it is already running.  And even a non-RT
process will stick on its disallowed CPU as long as nothing else runs
there.

Learnt this the hard way from the hotplug CPU patch...
Rusty.
--
Premature optmztion is rt of all evl. --DK

  reply	other threads:[~2001-04-17 10:23 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-04-10  0:08 [PATCH] Process pinning Nick Pollitt
2001-04-11 11:05 ` Rusty Russell [this message]
2001-04-17 16:17   ` Tim Hockin
2001-04-17 19:25     ` Andrew Morton
2001-04-18  1:24 ` Albert D. Cahalan

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