Messages in this thread | | | Date | Thu, 10 Aug 2006 21:49:50 +0900 | From | KAMEZAWA Hiroyuki <> | Subject | Re: Re : sparsemem usage |
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On Thu, 10 Aug 2006 14:40:52 +0200 (CEST) moreau francis <francis_moreau2000@yahoo.fr> wrote: > > BTW, ioresouce information (see kernel/resouce.c) > > > > [kamezawa@aworks Development]$ cat /proc/iomem | grep RAM > > 00000000-0009fbff : System RAM > > 000a0000-000bffff : Video RAM area > > 00100000-2dfeffff : System RAM > > > > is not enough ? > > > > well actually you show that to get a really simple information, ie does > a page exist ?, we need to parse some kernel data structures like > ioresource (which is, IMHO, hackish) or duplicate in each architecture > some data to keep track of existing pages. >
becasue memory map from e820(x86) or efi(ia64) are registered to iomem_resource, we should avoid duplicates that information. kdump and memory hotplug uses this information. (memory hotplug updates this iomem_resource.)
Implementing "page_is_exist" function based on ioresouce is one of generic and rubust way to go, I think. (if performance of list walking is problem, enhancing ioresouce code is better.)
-Kame
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