[lkml]   [2005]   [Aug]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC][patch 0/2] mm: remove PageReserved
--Russell King <> wrote (on Tuesday, August 09, 2005 08:08:53 +0100):

> On Tue, Aug 09, 2005 at 02:59:53PM +1000, Nick Piggin wrote:
>> That would work for swsusp, but there are other users that want to
>> know if a struct page is valid ram (eg. ioremap), so in that case
>> swsusp would not be able to mess with the flag.
> The usage of "valid ram" here is confusing - that's not what PageReserved
> is all about. It's about valid RAM which is managed by method other
> than the usual page counting. Non-reserved RAM is also valid RAM, but
> is managed by the kernel in the usual way.
> The former is available for remap_pfn_range and ioremap, the latter is
> not.
> On the other hand, the validity of an apparant RAM address can only be
> tested using its pfn with pfn_valid().
> Can we straighten out the terminology so it's less confusing please?

pfn_valid() doesn't tell you it's RAM or not - it tells you whether you
have a backing struct page for that address. Could be an IO mapped device,
a small memory hole, whatever.


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-08-09 16:41    [W:0.118 / U:4.988 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site