[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <200711080220.59086.ak@suse.de>
Date: Thu, 8 Nov 2007 02:20:58 +0100
From: Andi Kleen <ak@...e.de>
To: Matt Mackall <mpm@...enic.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
Marin Mitov <mitov@...p.bas.bg>, linux-kernel@...r.kernel.org,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...e.hu>
Subject: Re: is minimum udelay() not respected in preemptible SMP kernel-2.6.23?
> But I think we'd be best off stashing a single bit somewhere and
> checking it at migrate time (relatively infrequent) rather than
> copying and zeroing out a potentially enormous affinity mask every
> time we disable migration (often, and in fast paths). Perhaps adding
> TASK_PINNED to the task state flags would do it?
It would need to be a count to be able to nest it.
> > get_cpu() etc. could be changed to use this then too.
>
> Some users of get_cpu might be relying on it to avoid actual
> preemption. In other words, we should have introduced a
> migrate_disable() when we first discovered the preempt/per_cpu
> conflict.
Ok perhaps it would make sense to migrate it step by step :-
define a replacement for get_cpu and migrate over as users are getting
audited and eventually deprecate old one.
-Andi
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists