Messages in this thread | | | Date | Tue, 13 Jul 2004 11:48:29 -0700 | From | Andrew Morton <> | Subject | Re: [linux-audio-dev] Re: [announce] [patch] Voluntary Kernel Preemption Patch |
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Andrea Arcangeli <andrea@suse.de> wrote: > > On Mon, Jul 12, 2004 at 05:08:44PM -0700, Andrew Morton wrote: > > of code then it's pretty obvious what's happening. If the trace is due to > > a long irq-off time then it will point up into the offending > > local_irq_enable(). > > schedule should be called with irq enabled, and I noticed here it's not > (jnz work_resched is executed with irq off so there is a window for > schedule to be called with irq off): > > Index: linux-2.5/arch/i386/kernel/entry.S > =================================================================== > RCS file: /home/andrea/crypto/cvs/linux-2.5/arch/i386/kernel/entry.S,v > retrieving revision 1.86 > diff -u -p -r1.86 entry.S > --- linux-2.5/arch/i386/kernel/entry.S 23 May 2004 05:03:15 -0000 1.86 > +++ linux-2.5/arch/i386/kernel/entry.S 13 Jul 2004 04:21:55 -0000 > @@ -302,6 +310,7 @@ work_pending: > testb $_TIF_NEED_RESCHED, %cl > jz work_notifysig > work_resched: > + sti > call schedule > cli # make sure we don't miss an interrupt > # setting need_resched or sigpending
sys_sched_yield() also calls schedule() with local interrupts disabled. It's a bit grubby, but saves a few cycles. Nick and Ingo prefer it that way. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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