diff --git a/kernel/power/power.h b/kernel/power/power.h
index c81f0ed3eeba753dd918dc964adbc51cc314210d..98c41423f3b1013fd889c5b059056abc0ff5850a 100644
--- a/kernel/power/power.h
+++ b/kernel/power/power.h
@@ -55,7 +55,7 @@ struct snapshot_handle {
unsigned int page;
unsigned int page_offset;
unsigned int prev;
- struct pbe *pbe;
+ struct pbe *pbe, *last_pbe;
void *buffer;
unsigned int buf_offset;
};
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 513eef3391a0c9fe88960d64690a74351b31c797..3d9284100b22105e5323adf37c3ab4aff46e4391 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -401,62 +401,29 @@ static inline void create_pbe_list(struct pbe *pblist, unsigned int nr_pages)
}
}
-/**
- * On resume it is necessary to trace and eventually free the unsafe
- * pages that have been allocated, because they are needed for I/O
- * (on x86-64 we likely will "eat" these pages once again while
- * creating the temporary page translation tables)
- */
-
-struct eaten_page {
- struct eaten_page *next;
- char padding[PAGE_SIZE - sizeof(void *)];
-};
-
-static struct eaten_page *eaten_pages = NULL;
-
-static void release_eaten_pages(void)
-{
- struct eaten_page *p, *q;
-
- p = eaten_pages;
- while (p) {
- q = p->next;
- /* We don't want swsusp_free() to free this page again */
- ClearPageNosave(virt_to_page(p));
- free_page((unsigned long)p);
- p = q;
- }
- eaten_pages = NULL;
-}
+static unsigned int unsafe_pages;
/**
* @safe_needed - on resume, for storing the PBE list and the image,
* we can only use memory pages that do not conflict with the pages
- * which had been used before suspend.
+ * used before suspend.
*
* The unsafe pages are marked with the PG_nosave_free flag
- *
- * Allocated but unusable (ie eaten) memory pages should be marked
- * so that swsusp_free() can release them
+ * and we count them using unsafe_pages
*/
static inline void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
{
void *res;
+ res = (void *)get_zeroed_page(gfp_mask);
if (safe_needed)
- do {
+ while (res && PageNosaveFree(virt_to_page(res))) {
+ /* The page is unsafe, mark it for swsusp_free() */
+ SetPageNosave(virt_to_page(res));
+ unsafe_pages++;
res = (void *)get_zeroed_page(gfp_mask);
- if (res && PageNosaveFree(virt_to_page(res))) {
- /* This is for swsusp_free() */
- SetPageNosave(virt_to_page(res));
- ((struct eaten_page *)res)->next = eaten_pages;
- eaten_pages = res;
- }
- } while (res && PageNosaveFree(virt_to_page(res)));
- else
- res = (void *)get_zeroed_page(gfp_mask);
+ }
if (res) {
SetPageNosave(virt_to_page(res));
SetPageNosaveFree(virt_to_page(res));
@@ -751,6 +718,8 @@ static int mark_unsafe_pages(struct pbe *pblist)
return -EFAULT;
}
+ unsafe_pages = 0;
+
return 0;
}
@@ -828,42 +797,99 @@ static inline struct pbe *unpack_orig_addresses(unsigned long *buf,
}
/**
- * create_image - use metadata contained in the PBE list
+ * prepare_image - use metadata contained in the PBE list
* pointed to by pagedir_nosave to mark the pages that will
* be overwritten in the process of restoring the system
- * memory state from the image and allocate memory for
- * the image avoiding these pages
+ * memory state from the image ("unsafe" pages) and allocate
+ * memory for the image
+ *
+ * The idea is to allocate the PBE list first and then
+ * allocate as many pages as it's needed for the image data,
+ * but not to assign these pages to the PBEs initially.
+ * Instead, we just mark them as allocated and create a list
+ * of "safe" which will be used later
*/
-static int create_image(struct snapshot_handle *handle)
+struct safe_page {
+ struct safe_page *next;
+ char padding[PAGE_SIZE - sizeof(void *)];
+};
+
+static struct safe_page *safe_pages;
+
+static int prepare_image(struct snapshot_handle *handle)
{
int error = 0;
- struct pbe *p, *pblist;
+ unsigned int nr_pages = nr_copy_pages;
+ struct pbe *p, *pblist = NULL;
p = pagedir_nosave;
error = mark_unsafe_pages(p);
if (!error) {
- pblist = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 1);
+ pblist = alloc_pagedir(nr_pages, GFP_ATOMIC, 1);
if (pblist)
copy_page_backup_list(pblist, p);
free_pagedir(p, 0);
if (!pblist)
error = -ENOMEM;
}
- if (!error)
- error = alloc_data_pages(pblist, GFP_ATOMIC, 1);
+ safe_pages = NULL;
+ if (!error && nr_pages > unsafe_pages) {
+ nr_pages -= unsafe_pages;
+ while (nr_pages--) {
+ struct safe_page *ptr;
+
+ ptr = (struct safe_page *)get_zeroed_page(GFP_ATOMIC);
+ if (!ptr) {
+ error = -ENOMEM;
+ break;
+ }
+ if (!PageNosaveFree(virt_to_page(ptr))) {
+ /* The page is "safe", add it to the list */
+ ptr->next = safe_pages;
+ safe_pages = ptr;
+ }
+ /* Mark the page as allocated */
+ SetPageNosave(virt_to_page(ptr));
+ SetPageNosaveFree(virt_to_page(ptr));
+ }
+ }
if (!error) {
- release_eaten_pages();
pagedir_nosave = pblist;
} else {
- pagedir_nosave = NULL;
handle->pbe = NULL;
- nr_copy_pages = 0;
- nr_meta_pages = 0;
+ swsusp_free();
}
return error;
}
+static void *get_buffer(struct snapshot_handle *handle)
+{
+ struct pbe *pbe = handle->pbe, *last = handle->last_pbe;
+ struct page *page = virt_to_page(pbe->orig_address);
+
+ if (PageNosave(page) && PageNosaveFree(page)) {
+ /*
+ * We have allocated the "original" page frame and we can
+ * use it directly to store the read page
+ */
+ pbe->address = 0;
+ if (last && last->next)
+ last->next = NULL;
+ return (void *)pbe->orig_address;
+ }
+ /*
+ * The "original" page frame has not been allocated and we have to
+ * use a "safe" page frame to store the read page
+ */
+ pbe->address = (unsigned long)safe_pages;
+ safe_pages = safe_pages->next;
+ if (last)
+ last->next = pbe;
+ handle->last_pbe = pbe;
+ return (void *)pbe->address;
+}
+
/**
* snapshot_write_next - used for writing the system memory snapshot.
*
@@ -908,15 +934,16 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count)
} else if (handle->prev <= nr_meta_pages) {
handle->pbe = unpack_orig_addresses(buffer, handle->pbe);
if (!handle->pbe) {
- error = create_image(handle);
+ error = prepare_image(handle);
if (error)
return error;
handle->pbe = pagedir_nosave;
- handle->buffer = (void *)handle->pbe->address;
+ handle->last_pbe = NULL;
+ handle->buffer = get_buffer(handle);
}
} else {
handle->pbe = handle->pbe->next;
- handle->buffer = (void *)handle->pbe->address;
+ handle->buffer = get_buffer(handle);
}
handle->prev = handle->page;
}