Re: [PATCH 2/3] swsusp: move snapshot-handling functions to snapshot.c
From: Rafael J. Wysocki
Date: Mon Oct 31 2005 - 14:36:14 EST
Hi,
On Sunday, 30 of October 2005 20:52, Pavel Machek wrote:
> Hi!
>
> > This patch moves the snapshot-handling functions remaining in swsusp.c
> > to snapshot.c (ie. it moves the code without changing the functionality).
> >
>
> I'm sorry, but I acked this one too quickly. I'd prefer to keep "relocate" code where
> it is, and define "must not collide" as a part of interface. That will keep snapshot.c
> smaller/simpler,
Speaking of simplifications and having seen your code I hope you will agree with
the appended patch against vanilla 2.6.14-git3 (it reduces the duplication of code,
and replaces swsusp_pagedir_relocate with a simpler mechanism).
Greetings,
Rafael
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
kernel/power/power.h | 6 +-
kernel/power/snapshot.c | 121 +++++++++++++++++++++++++++++++++--------
kernel/power/swsusp.c | 139 ++----------------------------------------------
3 files changed, 109 insertions(+), 157 deletions(-)
Index: linux-2.6.14-git3/kernel/power/power.h
===================================================================
--- linux-2.6.14-git3.orig/kernel/power/power.h 2005-10-31 20:27:30.000000000 +0100
+++ linux-2.6.14-git3/kernel/power/power.h 2005-10-31 20:29:31.000000000 +0100
@@ -66,7 +66,11 @@
extern asmlinkage int swsusp_arch_resume(void);
extern int restore_highmem(void);
-extern struct pbe * alloc_pagedir(unsigned nr_pages);
+extern void free_pagedir(struct pbe *pblist);
+extern struct pbe *alloc_pagedir(unsigned nr_pages, int need_safe);
extern void create_pbe_list(struct pbe *pblist, unsigned nr_pages);
+extern int alloc_data_pages(struct pbe *pblist, int need_safe);
extern void swsusp_free(void);
extern int enough_swap(unsigned nr_pages);
+extern void mark_unsafe_pages(struct pbe *pblist);
+extern void copy_page_backup_list(struct pbe *dst, struct pbe *src);
Index: linux-2.6.14-git3/kernel/power/snapshot.c
===================================================================
--- linux-2.6.14-git3.orig/kernel/power/snapshot.c 2005-10-31 20:27:30.000000000 +0100
+++ linux-2.6.14-git3/kernel/power/snapshot.c 2005-10-31 20:29:31.000000000 +0100
@@ -212,12 +212,44 @@
BUG_ON(pbe);
}
+/**
+ * @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.
+ *
+ * The unsafe pages are marked with the help of SetPageNosaveFree()
+ * in mark_unsafe_pages()
+ *
+ * Allocated but unusable (ie eaten) memory pages should be marked
+ * so that swsusp_free() can release them
+ */
+
+static inline unsigned long snapshot_get_page(gfp_t gfp_mask, int safe_needed)
+{
+ unsigned long m;
+
+ if (safe_needed)
+ do {
+ m = get_zeroed_page(gfp_mask);
+ if (m && PageNosaveFree(virt_to_page(m)))
+ /* This is for swsusp_free() */
+ SetPageNosave(virt_to_page(m));
+ } while (m && PageNosaveFree(virt_to_page(m)));
+ else
+ m = get_zeroed_page(gfp_mask);
+ if (m) {
+ /* This is for swsusp_free() */
+ SetPageNosave(virt_to_page(m));
+ SetPageNosaveFree(virt_to_page(m));
+ }
+ return m;
+}
/**
* free_pagedir - free pages allocated with alloc_pagedir()
*/
-static void free_pagedir(struct pbe *pblist)
+void free_pagedir(struct pbe *pblist)
{
struct pbe *pbe;
@@ -270,22 +302,14 @@
pr_debug("create_pbe_list(): initialized %d PBEs\n", num);
}
-static void *alloc_image_page(void)
+static inline void *alloc_image_page(int safe_needed)
{
- void *res = (void *)get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
- if (res) {
- SetPageNosave(virt_to_page(res));
- SetPageNosaveFree(virt_to_page(res));
- }
- return res;
+ return (void *)snapshot_get_page(GFP_ATOMIC | __GFP_COLD, safe_needed);
}
/**
* alloc_pagedir - Allocate the page directory.
*
- * First, determine exactly how many pages we need and
- * allocate them.
- *
* We arrange the pages in a chain: each page is an array of PBES_PER_PAGE
* struct pbe elements (pbes) and the last element in the page points
* to the next page.
@@ -293,7 +317,7 @@
* On each page we set up a list of struct_pbe elements.
*/
-struct pbe *alloc_pagedir(unsigned nr_pages)
+struct pbe *alloc_pagedir(unsigned nr_pages, int safe_needed)
{
unsigned num;
struct pbe *pblist, *pbe;
@@ -302,12 +326,12 @@
return NULL;
pr_debug("alloc_pagedir(): nr_pages = %d\n", nr_pages);
- pblist = alloc_image_page();
+ pblist = alloc_image_page(safe_needed);
/* FIXME: rewrite this ugly loop */
for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
pbe = pbe->next, num += PBES_PER_PAGE) {
pbe += PB_PAGE_SKIP;
- pbe->next = alloc_image_page();
+ pbe->next = alloc_image_page(safe_needed);
}
if (!pbe) { /* get_zeroed_page() failed */
free_pagedir(pblist);
@@ -316,6 +340,18 @@
return pblist;
}
+int alloc_data_pages(struct pbe *pblist, int safe_needed)
+{
+ struct pbe *p;
+
+ for_each_pbe (p, pblist) {
+ p->address = (unsigned long)alloc_image_page(safe_needed);
+ if (!p->address)
+ return -ENOMEM;
+ }
+ return 0;
+}
+
/**
* Free pages we allocated for suspend. Suspend pages are alocated
* before atomic copy, so we need to free them after resume.
@@ -355,24 +391,20 @@
(nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
}
-
static struct pbe *swsusp_alloc(unsigned nr_pages)
{
- struct pbe *pblist, *p;
+ struct pbe *pblist;
- if (!(pblist = alloc_pagedir(nr_pages))) {
+ if (!(pblist = alloc_pagedir(nr_pages, 0))) {
printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
return NULL;
}
create_pbe_list(pblist, nr_pages);
- for_each_pbe (p, pblist) {
- p->address = (unsigned long)alloc_image_page();
- if (!p->address) {
- printk(KERN_ERR "suspend: Allocating image pages failed.\n");
- swsusp_free();
- return NULL;
- }
+ if (alloc_data_pages(pblist, 0)) {
+ printk(KERN_ERR "suspend: Allocating image pages failed.\n");
+ swsusp_free();
+ return NULL;
}
return pblist;
@@ -433,3 +465,44 @@
printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages);
return 0;
}
+
+/* Resume-related functions */
+
+void mark_unsafe_pages(struct pbe *pblist)
+{
+ struct zone *zone;
+ unsigned long zone_pfn;
+ struct pbe *p;
+
+ if (!pblist) /* a sanity check */
+ return;
+
+ /* Clear page flags */
+ for_each_zone (zone) {
+ for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
+ if (pfn_valid(zone_pfn + zone->zone_start_pfn))
+ ClearPageNosaveFree(pfn_to_page(zone_pfn +
+ zone->zone_start_pfn));
+ }
+
+ /* Mark orig addresses */
+ for_each_pbe (p, pblist)
+ SetPageNosaveFree(virt_to_page(p->orig_address));
+
+}
+
+void copy_page_backup_list(struct pbe *dst, struct pbe *src)
+{
+ /* We assume both lists contain the same number of elements */
+ while (src) {
+ dst->orig_address = src->orig_address;
+ dst->swap_address = src->swap_address;
+ dst = dst->next;
+ src = src->next;
+ }
+}
+
+unsigned long get_safe_page(gfp_t gfp_mask)
+{
+ return (unsigned long)snapshot_get_page(gfp_mask, 1);
+}
Index: linux-2.6.14-git3/kernel/power/swsusp.c
===================================================================
--- linux-2.6.14-git3.orig/kernel/power/swsusp.c 2005-10-31 20:27:30.000000000 +0100
+++ linux-2.6.14-git3/kernel/power/swsusp.c 2005-10-31 20:29:31.000000000 +0100
@@ -635,130 +635,6 @@
return error;
}
-/**
- * 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.
- *
- * We don't know which pages are usable until we allocate them.
- *
- * Allocated but unusable (ie eaten) memory pages are marked so that
- * swsusp_free() can release them
- */
-
-unsigned long get_safe_page(gfp_t gfp_mask)
-{
- unsigned long m;
-
- do {
- m = get_zeroed_page(gfp_mask);
- 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;
-}
-
-/**
- * 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
- * pages later
- */
-
-static int check_pagedir(struct pbe *pblist)
-{
- struct pbe *p;
-
- /* This is necessary, so that we can free allocated pages
- * in case of failure
- */
- for_each_pbe (p, pblist)
- p->address = 0UL;
-
- for_each_pbe (p, pblist) {
- p->address = get_safe_page(GFP_ATOMIC);
- if (!p->address)
- return -ENOMEM;
- }
- return 0;
-}
-
-/**
- * swsusp_pagedir_relocate - It is possible, that some memory pages
- * occupied by the list of PBEs collide with pages where we're going to
- * restore from the loaded pages later. We relocate them here.
- */
-
-static struct pbe * swsusp_pagedir_relocate(struct pbe *pblist)
-{
- struct zone *zone;
- unsigned long zone_pfn;
- struct pbe *pbpage, *tail, *p;
- void *m;
- int rel = 0;
-
- if (!pblist) /* a sanity check */
- return NULL;
-
- pr_debug("swsusp: Relocating pagedir (%lu pages to check)\n",
- swsusp_info.pagedir_pages);
-
- /* Clear page flags */
-
- for_each_zone (zone) {
- for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
- if (pfn_valid(zone_pfn + zone->zone_start_pfn))
- ClearPageNosaveFree(pfn_to_page(zone_pfn +
- zone->zone_start_pfn));
- }
-
- /* Mark orig addresses */
-
- for_each_pbe (p, pblist)
- 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_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;
- 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;
-
- rel++;
- }
- tail = pbpage + PB_PAGE_SKIP;
- }
-
- /* 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;
-}
-
/*
* Using bio to read from swap.
* This code requires a bit more work than just using buffer heads
@@ -905,9 +781,6 @@
/**
* data_read - Read image pages from swap.
- *
- * You do not need to check for overlaps, check_pagedir()
- * already did that.
*/
static int data_read(struct pbe *pblist)
@@ -997,20 +870,22 @@
int error = 0;
struct pbe *p;
- if (!(p = alloc_pagedir(nr_copy_pages)))
+ if (!(p = alloc_pagedir(nr_copy_pages, 0)))
return -ENOMEM;
if ((error = read_pagedir(p)))
return error;
-
create_pbe_list(p, nr_copy_pages);
-
- if (!(pagedir_nosave = swsusp_pagedir_relocate(p)))
+ mark_unsafe_pages(p);
+ if (!(pagedir_nosave = alloc_pagedir(nr_copy_pages, 1)))
return -ENOMEM;
+ create_pbe_list(pagedir_nosave, nr_copy_pages);
+ copy_page_backup_list(pagedir_nosave, p);
+ free_pagedir(p);
/* Allocate memory for the image and read the data from swap */
- error = check_pagedir(pagedir_nosave);
+ error = alloc_data_pages(pagedir_nosave, 1);
if (!error)
error = data_read(pagedir_nosave);
-
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