Re: [PATCH] Hibernate: save e820 table to snapshot header for comparison

Pavel Machek
2014-08-12T09:41:36Z

Hi!

> [ 7.374714] e820: Check memory region: [mem 0x0000000100000000-0x000000187fffffff] usable
> [ 7.378041] PM: Image mismatch: memory map changed
> [ 7.381314] PM: Read 2398272 kbytes in 0.27 seconds (8882.48 MB/s)
> [ 7.385476] PM: Error -1 resuming
> [ 7.388730] PM: Failed to load hibernation image, recovering.
> [ 7.688989] PM: Basic memory bitmaps freed

Nice!

> +int save_mem_chk_map(struct mementry *mem_chk_map)

I'd prefer _chk_ -> _check_

> +{
> + int i;
> +
> + for (i = 0; i < e820.nr_map; i++) {
> + struct e820entry *ei = &e820.map[i];
> +
> + if (i > MEMCHKMAX)
> + break;

MEMCHKMAX -> MEM_CHECK_MAX?

What happens when there are more entries?

> +bool check_mem_map(int mem_chk_entries, struct mementry *mem_chk_map)
> +{
> + int i;
> + bool ret = true;
> +
> + if (mem_chk_entries != e820.nr_map) {
> + pr_err("PM: memory check entry number %d:%d\n",
> + mem_chk_entries, e820.nr_map);
> + ret = false;
> + goto Print_map;
> + }

I'd change name to something like mem_map_matches() or mem_map_ok(),
so that it is clear what true/false means.

Can you reduce ammount of gotos?

> + for (i = 0; i < mem_chk_entries; i++) {
> + struct e820entry *ei = &e820.map[i];
> +
> + if (i > MEMCHKMAX)
> + break;
> +
> + /* check regions not E820_RAM or E820_RESERVED_KERN */
> + if (ei->type != E820_RAM && ei->type != E820_RESERVED_KERN) {
> + if (mem_chk_map[i].addr != ei->addr ||
> + mem_chk_map[i].size != ei->size ||
> + mem_chk_map[i].type != ei->type) {
> + ret = false;
> + goto Print_map;
> + }
> + }

Why don't you check RAM and RESERVED_KERN, too? If those changed, we
don't want to resume, either, right?

(Plus, you only check ei->type; you should check mem_chk_map[].type,
too AFAICT).

Thanks,
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html