[RFC][PATCH 1/3] swsusp: Do not use page flags directly

Rafael J. Wysocki
2007-03-04T14:07:44Z

Make swsusp stop using SetPageNosave(), SetPageNosaveFree() and friends
directly.

This way the amount of changes made in the next patch is smaller.

---
include/linux/suspend.h | 33 +++++++++++++++++++++++++++++++++
kernel/power/snapshot.c | 48 +++++++++++++++++++++++++-----------------------
mm/page_alloc.c | 6 +++---
3 files changed, 61 insertions(+), 26 deletions(-)

Index: linux-2.6.21-rc2/include/linux/suspend.h
===================================================================
--- linux-2.6.21-rc2.orig/include/linux/suspend.h 2007-03-02 09:05:53.000000000 +0100
+++ linux-2.6.21-rc2/include/linux/suspend.h 2007-03-02 09:24:02.000000000 +0100
@@ -8,6 +8,7 @@
#include <linux/notifier.h>
#include <linux/init.h>
#include <linux/pm.h>
+#include <linux/mm.h>

/* struct pbe is used for creating lists of pages that should be restored
* atomically during the resume from disk, because the page frames they have
@@ -49,6 +50,38 @@ void __save_processor_state(struct saved
void __restore_processor_state(struct saved_context *ctxt);
unsigned long get_safe_page(gfp_t gfp_mask);

+/* Page management functions for the software suspend (swsusp) */
+
+static inline void swsusp_set_page_forbidden(struct page *page)
+{
+ SetPageNosave(page);
+}
+
+static inline int swsusp_page_is_forbidden(struct page *page)
+{
+ return PageNosave(page);
+}
+
+static inline void swsusp_unset_page_forbidden(struct page *page)
+{
+ ClearPageNosave(page);
+}
+
+static inline void swsusp_set_page_free(struct page *page)
+{
+ SetPageNosaveFree(page);
+}
+
+static inline int swsusp_page_is_free(struct page *page)
+{
+ return PageNosaveFree(page);
+}
+
+static inline void swsusp_unset_page_free(struct page *page)
+{
+ ClearPageNosaveFree(page);
+}
+
/*
* XXX: We try to keep some more pages free so that I/O operations succeed
* without paging. Might this be more?
Index: linux-2.6.21-rc2/kernel/power/snapshot.c
===================================================================
--- linux-2.6.21-rc2.orig/kernel/power/snapshot.c 2007-03-02 09:05:53.000000000 +0100
+++ linux-2.6.21-rc2/kernel/power/snapshot.c 2007-03-02 09:27:06.000000000 +0100
@@ -67,15 +67,15 @@ static void *get_image_page(gfp_t gfp_ma

res = (void *)get_zeroed_page(gfp_mask);
if (safe_needed)
- while (res && PageNosaveFree(virt_to_page(res))) {
+ while (res && swsusp_page_is_free(virt_to_page(res))) {
/* The page is unsafe, mark it for swsusp_free() */
- SetPageNosave(virt_to_page(res));
+ swsusp_set_page_forbidden(virt_to_page(res));
allocated_unsafe_pages++;
res = (void *)get_zeroed_page(gfp_mask);
}
if (res) {
- SetPageNosave(virt_to_page(res));
- SetPageNosaveFree(virt_to_page(res));
+ swsusp_set_page_forbidden(virt_to_page(res));
+ swsusp_set_page_free(virt_to_page(res));
}
return res;
}
@@ -91,8 +91,8 @@ static struct page *alloc_image_page(gfp

page = alloc_page(gfp_mask);
if (page) {
- SetPageNosave(page);
- SetPageNosaveFree(page);
+ swsusp_set_page_forbidden(page);
+ swsusp_set_page_free(page);
}
return page;
}
@@ -110,9 +110,9 @@ static inline void free_image_page(void

page = virt_to_page(addr);

- ClearPageNosave(page);
+ swsusp_unset_page_forbidden(page);
if (clear_nosave_free)
- ClearPageNosaveFree(page);
+ swsusp_unset_page_free(page);

__free_page(page);
}
@@ -615,7 +615,8 @@ static struct page *saveable_highmem_pag

BUG_ON(!PageHighMem(page));

- if (PageNosave(page) || PageReserved(page) || PageNosaveFree(page))
+ if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page) ||
+ PageReserved(page))
return NULL;

return page;
@@ -681,7 +682,7 @@ static struct page *saveable_page(unsign

BUG_ON(PageHighMem(page));

- if (PageNosave(page) || PageNosaveFree(page))
+ if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
return NULL;

if (PageReserved(page) && pfn_is_nosave(pfn))
@@ -821,9 +822,10 @@ void swsusp_free(void)
if (pfn_valid(pfn)) {
struct page *page = pfn_to_page(pfn);

- if (PageNosave(page) && PageNosaveFree(page)) {
- ClearPageNosave(page);
- ClearPageNosaveFree(page);
+ if (swsusp_page_is_forbidden(page) &&
+ swsusp_page_is_free(page)) {
+ swsusp_unset_page_forbidden(page);
+ swsusp_unset_page_free(page);
__free_page(page);
}
}
@@ -1146,7 +1148,7 @@ static int mark_unsafe_pages(struct memo
max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
if (pfn_valid(pfn))
- ClearPageNosaveFree(pfn_to_page(pfn));
+ swsusp_unset_page_free(pfn_to_page(pfn));
}

/* Mark pages that correspond to the "original" pfns as "unsafe" */
@@ -1155,7 +1157,7 @@ static int mark_unsafe_pages(struct memo
pfn = memory_bm_next_pfn(bm);
if (likely(pfn != BM_END_OF_MAP)) {
if (likely(pfn_valid(pfn)))
- SetPageNosaveFree(pfn_to_page(pfn));
+ swsusp_set_page_free(pfn_to_page(pfn));
else
return -EFAULT;
}
@@ -1321,14 +1323,14 @@ prepare_highmem_image(struct memory_bitm
struct page *page;

page = alloc_page(__GFP_HIGHMEM);
- if (!PageNosaveFree(page)) {
+ if (!swsusp_page_is_free(page)) {
/* The page is "safe", set its bit the bitmap */
memory_bm_set_bit(bm, page_to_pfn(page));
safe_highmem_pages++;
}
/* Mark the page as allocated */
- SetPageNosave(page);
- SetPageNosaveFree(page);
+ swsusp_set_page_forbidden(page);
+ swsusp_set_page_free(page);
}
memory_bm_position_reset(bm);
safe_highmem_bm = bm;
@@ -1360,7 +1362,7 @@ get_highmem_page_buffer(struct page *pag
struct highmem_pbe *pbe;
void *kaddr;

- if (PageNosave(page) && PageNosaveFree(page)) {
+ if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {
/* We have allocated the "original" page frame and we can
* use it directly to store the loaded page.
*/
@@ -1522,14 +1524,14 @@ prepare_image(struct memory_bitmap *new_
error = -ENOMEM;
goto Free;
}
- if (!PageNosaveFree(virt_to_page(lp))) {
+ if (!swsusp_page_is_free(virt_to_page(lp))) {
/* The page is "safe", add it to the list */
lp->next = safe_pages_list;
safe_pages_list = lp;
}
/* Mark the page as allocated */
- SetPageNosave(virt_to_page(lp));
- SetPageNosaveFree(virt_to_page(lp));
+ swsusp_set_page_forbidden(virt_to_page(lp));
+ swsusp_set_page_free(virt_to_page(lp));
nr_pages--;
}
/* Free the reserved safe pages so that chain_alloc() can use them */
@@ -1558,7 +1560,7 @@ static void *get_buffer(struct memory_bi
if (PageHighMem(page))
return get_highmem_page_buffer(page, ca);

- if (PageNosave(page) && PageNosaveFree(page))
+ if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page))
/* We have allocated the "original" page frame and we can
* use it directly to store the loaded page.
*/
Index: linux-2.6.21-rc2/mm/page_alloc.c
===================================================================
--- linux-2.6.21-rc2.orig/mm/page_alloc.c 2007-03-02 09:03:43.000000000 +0100
+++ linux-2.6.21-rc2/mm/page_alloc.c 2007-03-02 09:11:54.000000000 +0100
@@ -770,8 +770,8 @@ void mark_free_pages(struct zone *zone)
if (pfn_valid(pfn)) {
struct page *page = pfn_to_page(pfn);

- if (!PageNosave(page))
- ClearPageNosaveFree(page);
+ if (!swsusp_page_is_forbidden(page))
+ swsusp_unset_page_free(page);
}

for (order = MAX_ORDER - 1; order >= 0; --order)
@@ -780,7 +780,7 @@ void mark_free_pages(struct zone *zone)

pfn = page_to_pfn(list_entry(curr, struct page, lru));
for (i = 0; i < (1UL << order); i++)
- SetPageNosaveFree(pfn_to_page(pfn + i));
+ swsusp_set_page_free(pfn_to_page(pfn + i));
}

spin_unlock_irqrestore(&zone->lock, flags);