Re: [PATCH][mm][Fix] swsusp: fix counting of highmem pages

From: Pavel Machek
Date: Sat Dec 03 2005 - 16:39:52 EST


Hi!

> The following patch fixes a problem with swsusp that causes suspend to
> fail on systems with the highmem zone, if many highmem pages are in use.
>
> It makes swsusp count the non-free highmem pages in a correct way
> and, consequently, release a sufficient amount of memory before suspend.
>
> Please apply (Pavel, please ack if you think the patch is ok).

Please don't, it's way too complex in my eyes. Sorry, result of
misscomunication between me and Rafael.

> +static inline unsigned int get_kmalloc_size(void)
> +{
> +#define CACHE(x) \
> + if (sizeof(struct highmem_page) <= x) \
> + return x;
> +#include <linux/kmalloc_sizes.h>
> +#undef CACHE
> + return sizeof(struct highmem_page);
> +}
> +

Can we get rid of this uglyness...

> @@ -437,8 +446,14 @@
>
> static int enough_free_mem(unsigned int nr_pages)
> {
> - pr_debug("swsusp: available memory: %u pages\n", nr_free_pages());
> - return nr_free_pages() > (nr_pages + PAGES_FOR_IO +
> + struct zone *zone;
> + unsigned int n = 0;
> +
> + for_each_zone (zone)
> + if (!is_highmem(zone))
> + n += zone->free_pages;
> + pr_debug("swsusp: available memory: %u pages\n", n);
> + return n > (nr_pages + PAGES_FOR_IO +
> (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
> }
>

And just use 2% approximation here, too?

> Index: linux-2.6.15-rc3-mm1/kernel/power/swsusp.c
> ===================================================================
> --- linux-2.6.15-rc3-mm1.orig/kernel/power/swsusp.c 2005-12-03 00:14:49.000000000 +0100
> +++ linux-2.6.15-rc3-mm1/kernel/power/swsusp.c 2005-12-03 21:25:07.000000000 +0100
> @@ -635,7 +635,8 @@
> printk("Shrinking memory... ");
> do {
> #ifdef FAST_FREE
> - tmp = count_data_pages() + count_highmem_pages();
> + tmp = 2 * count_highmem_pages();
> + tmp += tmp / 50 + count_data_pages();
> tmp += (tmp + PBES_PER_PAGE - 1) / PBES_PER_PAGE +
> PAGES_FOR_IO;
> for_each_zone (zone)

This part is okay. Just make enough_free_mem use similar code. (If
possible, share the code, it is really computing the same thing).

Pavel
--
Thanks, Sharp!
-
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