Date: Wed, 13 Feb 2008 07:30:04 GMT From: Arthur Hartwig <Arthur.Hartwig@nokia.com> To: freebsd-acpi@FreeBSD.org Subject: Re: kern/120515: [acpi] [patch] acpi_alloc_wakeup_handler: can't alloc wake memory Message-ID: <200802130730.m1D7U4Ow030463@freefall.freebsd.org>
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The following reply was made to PR kern/120515; it has been noted by GNATS.
From: Arthur Hartwig <Arthur.Hartwig@nokia.com>
To: ext Dan Lukes <dan@obluda.cz>
Cc: bug-followup@FreeBSD.org
Subject: Re: kern/120515: [acpi] [patch] acpi_alloc_wakeup_handler: can't
alloc wake memory
Date: Wed, 13 Feb 2008 16:58:47 +1000
ext Dan Lukes wrote:
> Duplicate of kern/119356 but with different fix
G'day Dan,
Thanks for the pointer to the other PR.
Based on the comments preceding the code I suggested be changed, I
suspect the the vm subsystem originally added pages to the head of the
free queues and removed them from the head of the free queues so that
the first pages added to the free queues were the last actually
allocated. Unfortunately this scheme has the undesirable consequence
that once the system is up and running a free page is more likely to be
reused soon thus obliterating information that might be useful to
someone dredging a crash dump for clues why a panic occurred. But I
haven't done the research.
Your proposed change in PR 119356 looks OK to me apart from the
disadvantages you mention AND it doesn't help anything else that might
need to allocate memory at low physical addresses (not that I know of
anything).
Arthur
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