Re: [patch] max-sectors-2.6.9-rc1-bk14-A0
From: Jens Axboe (axboe_at_suse.de)
Date: 09/08/04
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- In reply to: Ingo Molnar: "Re: [patch] max-sectors-2.6.9-rc1-bk14-A0"
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Date: Wed, 8 Sep 2004 13:05:44 +0200 To: Ingo Molnar <mingo@elte.hu>
On Wed, Sep 08 2004, Ingo Molnar wrote:
>
> * Jens Axboe <axboe@suse.de> wrote:
>
> > Wasn't the move of the ide_lock grabbing enough to solve this problem
> > by itself?
>
> yes and no. It does solve it for the specific case of the
> voluntary-preemption patches: there hardirqs can run in separate kernel
> threads which are preemptable (no HARDIRQ_OFFSET). In stock Linux
> hardirqs are not preemptable so the earlier dropping of ide_lock doesnt
> solve the latency.
>
> so in the upstream kernel the only solution is to reduce the size of IO.
> (I'll push the hardirq patches later on too but their acceptance should
> not hinder people in achieving good latencies.) It can be useful for
> other reasons too to reduce IO, so why not? The patch certainly causes
> no overhead anywhere in the block layer and people are happy with it.
I'm not particularly against it, I was just curious. The splitting of
max_sectors into a max_hw_sectors is something we need to do anyways, so
I'm quite fine with the patch. You can add my signed-off-by too.
-- Jens Axboe - 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/
- Previous message: Helge Hafting: "Re: New proposed DRM interface design"
- In reply to: Ingo Molnar: "Re: [patch] max-sectors-2.6.9-rc1-bk14-A0"
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