[PATCH] swsusp: rework memory freeing on resume
The following patch makes swsusp use the PG_nosave and PG_nosave_free flags to
mark pages that should be freed in case of an error during resume.
This allows us to simplify the code and to use swsusp_free() in all of the
swsusp's resume error paths, which makes them actually work.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index f6abfdb..50667f4 100644
--- a/kernel/power/swsusp.c
+++ b/kernel/power/swsusp.c
@@ -629,6 +629,11 @@
* execution continues at place where swsusp_arch_suspend was called
*/
BUG_ON(!error);
+ /* The only reason why swsusp_arch_resume() can fail is memory being
+ * very tight, so we have to free it as soon as we can to avoid
+ * subsequent failures
+ */
+ swsusp_free();
restore_processor_state();
restore_highmem();
touch_softlockup_watchdog();
@@ -644,54 +649,28 @@
*
* We don't know which pages are usable until we allocate them.
*
- * Allocated but unusable (ie eaten) memory pages are linked together
- * to create a list, so that we can free them easily
- *
- * We could have used a type other than (void *)
- * for this purpose, but ...
+ * Allocated but unusable (ie eaten) memory pages are marked so that
+ * swsusp_free() can release them
*/
-static void **eaten_memory = NULL;
-static inline void eat_page(void *page)
-{
- void **c;
-
- c = eaten_memory;
- eaten_memory = page;
- *eaten_memory = c;
-}
-
-unsigned long get_usable_page(gfp_t gfp_mask)
+unsigned long get_safe_page(gfp_t gfp_mask)
{
unsigned long m;
- m = get_zeroed_page(gfp_mask);
- while (!PageNosaveFree(virt_to_page(m))) {
- eat_page((void *)m);
+ do {
m = get_zeroed_page(gfp_mask);
- if (!m)
- break;
+ if (m && PageNosaveFree(virt_to_page(m)))
+ /* This is for swsusp_free() */
+ SetPageNosave(virt_to_page(m));
+ } while (m && PageNosaveFree(virt_to_page(m)));
+ if (m) {
+ /* This is for swsusp_free() */
+ SetPageNosave(virt_to_page(m));
+ SetPageNosaveFree(virt_to_page(m));
}
return m;
}
-void free_eaten_memory(void)
-{
- unsigned long m;
- void **c;
- int i = 0;
-
- c = eaten_memory;
- while (c) {
- m = (unsigned long)c;
- c = *c;
- free_page(m);
- i++;
- }
- eaten_memory = NULL;
- pr_debug("swsusp: %d unused pages freed\n", i);
-}
-
/**
* check_pagedir - We ensure here that pages that the PBEs point to
* won't collide with pages where we're going to restore from the loaded
@@ -709,7 +688,7 @@
p->address = 0UL;
for_each_pbe (p, pblist) {
- p->address = get_usable_page(GFP_ATOMIC);
+ p->address = get_safe_page(GFP_ATOMIC);
if (!p->address)
return -ENOMEM;
}
@@ -728,7 +707,7 @@
unsigned long zone_pfn;
struct pbe *pbpage, *tail, *p;
void *m;
- int rel = 0, error = 0;
+ int rel = 0;
if (!pblist) /* a sanity check */
return NULL;
@@ -736,41 +715,37 @@
pr_debug("swsusp: Relocating pagedir (%lu pages to check)\n",
swsusp_info.pagedir_pages);
- /* Set page flags */
+ /* Clear page flags */
for_each_zone (zone) {
for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
- SetPageNosaveFree(pfn_to_page(zone_pfn +
+ if (pfn_valid(zone_pfn + zone->zone_start_pfn))
+ ClearPageNosaveFree(pfn_to_page(zone_pfn +
zone->zone_start_pfn));
}
- /* Clear orig addresses */
+ /* Mark orig addresses */
for_each_pbe (p, pblist)
- ClearPageNosaveFree(virt_to_page(p->orig_address));
+ SetPageNosaveFree(virt_to_page(p->orig_address));
tail = pblist + PB_PAGE_SKIP;
/* Relocate colliding pages */
for_each_pb_page (pbpage, pblist) {
- if (!PageNosaveFree(virt_to_page((unsigned long)pbpage))) {
- m = (void *)get_usable_page(GFP_ATOMIC | __GFP_COLD);
- if (!m) {
- error = -ENOMEM;
- break;
- }
+ if (PageNosaveFree(virt_to_page((unsigned long)pbpage))) {
+ m = (void *)get_safe_page(GFP_ATOMIC | __GFP_COLD);
+ if (!m)
+ return NULL;
memcpy(m, (void *)pbpage, PAGE_SIZE);
if (pbpage == pblist)
pblist = (struct pbe *)m;
else
tail->next = (struct pbe *)m;
-
- eat_page((void *)pbpage);
pbpage = (struct pbe *)m;
/* We have to link the PBEs again */
-
for (p = pbpage; p < pbpage + PB_PAGE_SKIP; p++)
if (p->next) /* needed to save the end */
p->next = p + 1;
@@ -780,15 +755,13 @@
tail = pbpage + PB_PAGE_SKIP;
}
- if (error) {
- printk("\nswsusp: Out of memory\n\n");
- free_pagedir(pblist);
- free_eaten_memory();
- pblist = NULL;
- /* Is this even worth handling? It should never ever happen, and we
- have just lost user's state, anyway... */
- } else
- printk("swsusp: Relocated %d pages\n", rel);
+ /* This is for swsusp_free() */
+ for_each_pb_page (pbpage, pblist) {
+ SetPageNosave(virt_to_page(pbpage));
+ SetPageNosaveFree(virt_to_page(pbpage));
+ }
+
+ printk("swsusp: Relocated %d pages\n", rel);
return pblist;
}
@@ -1006,9 +979,7 @@
break;
}
- if (error)
- free_pagedir(pblist);
- else
+ if (!error)
BUG_ON(i != swsusp_info.pagedir_pages);
return error;
@@ -1051,15 +1022,6 @@
if (!error)
error = data_read(pagedir_nosave);
- if (error) { /* We fail cleanly */
- free_eaten_memory();
- for_each_pbe (p, pagedir_nosave)
- if (p->address) {
- free_page(p->address);
- p->address = 0UL;
- }
- free_pagedir(pagedir_nosave);
- }
return error;
}