Re: [PATCH] BadRAM for 2.5.73-mm2

[Oleg Drokin <green@namesys.com>]

Hello!

On Wed, Jul 02, 2003 at 03:33:26AM +0000, steven.newbury1@ntlworld.com wrote:

> It will probably apply cleanly to 2.5.73 as well but I haven't checked it
> yet...

This

> It is based it on
> http://rick.vanrein.org/linux/badram/software/BadRAM-2.4.20.1.patch

and this patches both have a bug that effectively disables all highmem (if present)
when badram patch is activated. I contacted Rick, but never got any answer back.
(in fact I got an auto reply from some Debian bugtracking system, but that's about it).
Corrected 2.4.21 version of the patch is available at
http://linuxhacker.ru/patches/2.4.21-badram.diff

The arch/i386/mm/init.c part:
> +void __init one_highpage_init(struct page *page, int pfn, int bad_ppro,
> +                               _Bool *bad)
>   {
> +       *bad = 0;
>         if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) {
>                 ClearPageReserved(page);
>                 set_bit(PG_highmem, &page->flags);
>                 set_page_count(page, 1);
> -               __free_page(page);
> +#ifdef CONFIG_BADRAM
> +               if (PageBad(page))
> +                       *bad = 1;
> +               else
> +#else
> +                       __free_page(page);
> +#endif
>                 totalhigh_pages++;

should obviously get "#else" replaced with "#endif" and original "#endif" should be removed
because otherwise all of the highmem pages are either bad or used right from the initialisation.
(Yes, I have highmem (2G RAM) system with 2 bits bad and I am too lazy to to go to the store to
replace the RAM modules, so I given a patch a try and discovered this problem (which is there
for a long time it seems). I suspect that I am the only one who runs this patch on highmem system,
though ;) )

Bye,
    Oleg