Messages in this thread | | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH][mm][Fix] swsusp: fix counting of highmem pages | Date | Sun, 4 Dec 2005 00:11:29 +0100 |
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Hi,
[dropped Andrew from the CC list]
On Saturday, 3 of December 2005 22:40, Pavel Machek wrote: > 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...
Sure, we can.
> > @@ -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?
Well, I don't think so. It's checking free memory _after_ the highmem pages have been "saved" (ie we are ready to create the image and just check if there are enough non-highmem pages to do this). Here we _know_ exactly how many pages are needed for the image, so we don't need to use any "safety margins".
> > 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).
enough_free_mem() must not take highmem into account, so it has to use different code. IOW, the current implementation is buggy, so I'm trying to change it.
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