kern/120515: [acpi] [patch] acpi_alloc_wakeup_handler: can't alloc wake memory

[Arthur Hartwig]

The following reply was made to PR kern/120515; it has been noted by GNATS.

From: Arthur Hartwig <Arthur.Hartwig at nokia.com>
To: ext Dan Lukes <dan at obluda.cz>
Cc: bug-followup at 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