Re: [patch] VM accounting change

From: Terence Ripperda
Date: Thu Nov 11 2004 - 19:31:46 EST

On Thu, Nov 11, 2004 at 03:07:10PM -0800, akpm@xxxxxxxx wrote:
> VM_LOCKED|VM_IO doesn't seem to be a sane combination. VM_LOCKED means
> "don't page it out" and VM_IO means "an IO region". The kernel never even
> attempts to page out IO regions because they don't have reverse mappings.
> Heck, they don't even have pageframes.
> How about you drop the VM_LOCKED?

sounds good, I can do that.

on a related note, there are a couple of flags that I'm not 100% clear
on the difference between, mainly:


everything I've seen in the past has suggested that drivers set the
PG_reserved flag for memory allocations intended to be locked down in
memory for extensive dma (the bttv driver had always been pointed to
as an example of that).

I'm not clear how that differs from PG_locked and VM_LOCKED. is
PG_reserved still the suggested way to properly lock memory down, or
is there a more generally accepted method?


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