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From: Manfred Spraul <manfred@colorfullife.com>
To: Jens Axboe <axboe@suse.de>
Cc: linux-kernel@vger.kernel.org, Andre Hedrick <andre@linuxdiskcert.org>
Subject: Re: BIO Usage Error or Conflicting Designs
Date: Sun, 13 Jan 2002 22:09:06 +0100	[thread overview]
Message-ID: <3C41F772.543C2F85@colorfullife.com> (raw)

 
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> 
> Is this with the highmem debug stuff enabled? That's the only way I can
> see this BUG triggering, otherwise q->bounce_pfn _cannot_ be smaller
> than the max_pfn.
> 
Have you tested that?

Unless I misread arch/i386/kernel/setup.c, line 740 to 760, max_pfn is
the upper end of the highmem area, if highmem is configured.
For non-highmem setup, it's set to min(system_memory, 4 GB).
It was a local variable within setup_arch, and someone made it a global
variable.

I.e. max_pfn is 1 GB with Andre's setup.

His patch doesn't touch the bounce limit, the default limit from
blk_queue_make_request() is used: BLK_BOUNCE_HIGH, which is max_low_pfn.

max_low_pfn is 896 MB.

--> BUG in create_bounce(), because a request comes in with a bounce
limit less than the total system memory, and no highmem configured.

--
	Manfred

             reply	other threads:[~2002-01-13 21:09 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-01-13 21:09 Manfred Spraul [this message]
2002-01-14  7:23 ` BIO Usage Error or Conflicting Designs Jens Axboe
  -- strict thread matches above, loose matches on Subject: below --
2002-01-12 18:28 [PATCH] 1-2-3 GB Albert D. Cahalan
2002-01-12 19:07 ` BIO Usage Error or Conflicting Designs Andre Hedrick
2002-01-12 20:05   ` Jens Axboe
2002-01-13  1:15     ` Andre Hedrick
2002-01-13 12:59       ` Jens Axboe
2002-01-13 19:59         ` Andre Hedrick
2002-01-14  6:42           ` Jens Axboe

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