Hi,
On Monday, 31 of January 2005 00:19, Rafael J. Wysocki wrote:
> Hi,
>
> The following patch is (yet) an(other) attempt to eliminate the need for
> using higher
> order memory allocations on resume. It accomplishes this by replacing the
> array
> of page backup entries with a list, so it is only necessary to allocate
> individual
> memory pages. This approach makes it possible to avoid relocating many memory
> pages on resume (as a result, much less memory is used) and to simplify
> the assembly code that restores the image.
I have updated the resume patch to apply to the 2.6.11-rc3-mm1 kernel that
contains the suspend part and the x86_64-Speed-up-suspend patch. The patch
is only for x86-64 and i386.
[Note: without this patch the resume process fails on my box ("out of memory")
during every 7th - 8th suspend/resume cycle, on the average.]
I'm going to maintain this patch so that it's available for the next -mm
kernels (it will be available under http://www.sisk.pl/kernel/patches/).
The (updated) patch follows.
Greets,
Rafael
Signed-off-by: Rafael J. Wysocki <[EMAIL PROTECTED]>
diff -Nru linux-2.6.11-rc3-mm1-orig/arch/i386/power/swsusp.S
linux-2.6.11-rc3-mm1/arch/i386/power/swsusp.S
--- linux-2.6.11-rc3-mm1-orig/arch/i386/power/swsusp.S 2004-12-24
22:34:31.000000000 +0100
+++ linux-2.6.11-rc3-mm1/arch/i386/power/swsusp.S 2005-02-05
20:57:03.000000000 +0100
@@ -28,28 +28,28 @@
ret
ENTRY(swsusp_arch_resume)
- movl $swsusp_pg_dir-__PAGE_OFFSET,%ecx
- movl %ecx,%cr3
+ movl $swsusp_pg_dir-__PAGE_OFFSET,%ecx
+ movl %ecx,%cr3
- movl pagedir_nosave, %ebx
- xorl %eax, %eax
- xorl %edx, %edx
+ movl pagedir_nosave, %edx
+ testl %edx, %edx
+ jz done
.p2align 4,,7
copy_loop:
- movl 4(%ebx,%edx),%edi
- movl (%ebx,%edx),%esi
+ movl (%edx), %esi
+ movl 4(%edx), %edi
movl $1024, %ecx
rep
movsl
- incl %eax
- addl $16, %edx
- cmpl nr_copy_pages,%eax
- jb copy_loop
+ movl 12(%edx), %edx
+ testl %edx, %edx
+ jnz copy_loop
.p2align 4,,7
+done:
movl saved_context_esp, %esp
movl saved_context_ebp, %ebp
movl saved_context_ebx, %ebx
diff -Nru linux-2.6.11-rc3-mm1-orig/arch/x86_64/kernel/asm-offsets.c
linux-2.6.11-rc3-mm1/arch/x86_64/kernel/asm-offsets.c
--- linux-2.6.11-rc3-mm1-orig/arch/x86_64/kernel/asm-offsets.c 2005-02-05
20:49:04.000000000 +0100
+++ linux-2.6.11-rc3-mm1/arch/x86_64/kernel/asm-offsets.c 2005-02-05
20:57:03.000000000 +0100
@@ -62,8 +62,8 @@
offsetof (struct rt_sigframe32, uc.uc_mcontext));
BLANK();
#endif
- DEFINE(SIZEOF_PBE, sizeof(struct pbe));
DEFINE(pbe_address, offsetof(struct pbe, address));
DEFINE(pbe_orig_address, offsetof(struct pbe, orig_address));
+ DEFINE(pbe_next, offsetof(struct pbe, next));
return 0;
}
diff -Nru linux-2.6.11-rc3-mm1-orig/arch/x86_64/kernel/suspend_asm.S
linux-2.6.11-rc3-mm1/arch/x86_64/kernel/suspend_asm.S
--- linux-2.6.11-rc3-mm1-orig/arch/x86_64/kernel/suspend_asm.S 2005-02-05
20:49:04.000000000 +0100
+++ linux-2.6.11-rc3-mm1/arch/x86_64/kernel/suspend_asm.S 2005-02-05
20:57:03.000000000 +0100
@@ -54,15 +54,8 @@
movq %rax, %cr4; # turn PGE back on
movq pagedir_nosave(%rip), %rdx
- /* compute the limit */
- movl nr_copy_pages(%rip), %eax
- testl %eax, %eax
+ testq %rdx, %rdx
jz done
- movq %rdx,%r8
- movl $SIZEOF_PBE,%r9d
- mul %r9 # with rax, clobbers rdx
- movq %r8, %rdx
- addq %r8, %rax
loop:
/* get addresses from the pbe and copy the page */
movq pbe_address(%rdx), %rsi
@@ -72,9 +65,9 @@
movsq
/* progress to the next pbe */
- addq $SIZEOF_PBE, %rdx
- cmpq %rax, %rdx
- jb loop
+ movq pbe_next(%rdx), %rdx
+ testq %rdx, %rdx
+ jnz loop
done:
movl $24, %eax
movl %eax, %ds
diff -Nru linux-2.6.11-rc3-mm1-orig/kernel/power/swsusp.c
linux-2.6.11-rc3-mm1/kernel/power/swsusp.c
--- linux-2.6.11-rc3-mm1-orig/kernel/power/swsusp.c 2005-02-05
20:49:33.000000000 +0100
+++ linux-2.6.11-rc3-mm1/kernel/power/swsusp.c 2005-02-05 20:57:03.000000000
+0100
@@ -919,44 +919,96 @@
return 0;
}
-/*
- * We check here that pagedir & pages it points to won't collide with pages
- * where we're going to restore from the loaded pages later
+/**
+ * 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 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 ...
*/
-static int __init check_pagedir(void)
-{
- int i;
+static void **eaten_memory = NULL;
- for(i=0; i < nr_copy_pages; i++) {
- unsigned long addr;
+static unsigned long __init get_usable_page(unsigned gfp_mask) {
+ unsigned long m;
+ void **c = eaten_memory;
+
+ m = get_zeroed_page(gfp_mask);
+ while (does_collide_order(m, 0)) {
+ eaten_memory = (void *)m;
+ *eaten_memory = c;
+ c = eaten_memory;
+ m = get_zeroed_page(gfp_mask);
+ if (!m)
+ break;
+ }
+ return m;
+}
- do {
- addr = get_zeroed_page(GFP_ATOMIC);
- if(!addr)
- return -ENOMEM;
- } while (does_collide_order(addr, 0));
+static void __init free_eaten_memory(void) {
+ unsigned long m;
+ void **c;
+ int i = 0;
- (pagedir_nosave+i)->address = addr;
+ c = eaten_memory;
+ while (c) {
+ m = (unsigned long)c;
+ c = *c;
+ free_page(m);
+ i++;
}
- return 0;
+ eaten_memory = NULL;
+ pr_debug("swsusp: %d unused pages freed\n", i);
}
-static int __init swsusp_pagedir_relocate(void)
+/**
+ * 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 __init check_pagedir(struct pbe *pblist)
{
- /*
- * We have to avoid recursion (not to overflow kernel stack),
- * and that's why code looks pretty cryptic
+ struct pbe *p;
+
+ /* This is necessary, so that we can free allocated pages
+ * in case of failure
*/
- suspend_pagedir_t *old_pagedir = pagedir_nosave;
- void **eaten_memory = NULL;
- void **c = eaten_memory, *m, *f;
- int ret = 0;
+ for_each_pbe(p, pblist)
+ p->address = 0UL;
+
+ for_each_pbe(p, pblist) {
+ p->address = get_usable_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 * __init swsusp_pagedir_relocate(struct pbe *pblist)
+{
struct zone *zone;
- int i;
- struct pbe *p;
unsigned long zone_pfn;
+ struct pbe *pbpage, *tail, *p;
+ void *m;
+ int rel = 0, error = 0;
- printk("Relocating pagedir ");
+ if (!pblist) /* a sanity check */
+ return NULL;
+
+ pr_debug("swsusp: Relocating pagedir (%lu pages to check)\n",
+ swsusp_info.pagedir_pages);
/* Set page flags */
@@ -966,45 +1018,52 @@
zone->zone_start_pfn));
}
- /* Clear orig address */
+ /* Clear orig addresses */
- for(i = 0, p = pagedir_nosave; i < nr_copy_pages; i++, p++) {
+ for_each_pbe(p, pblist)
ClearPageNosaveFree(virt_to_page(p->orig_address));
- }
- if (!does_collide_order((unsigned long)old_pagedir, pagedir_order)) {
- printk("not necessary\n");
- return check_pagedir();
- }
+ tail = pblist + PB_PAGE_SKIP;
- while ((m = (void *) __get_free_pages(GFP_ATOMIC, pagedir_order)) !=
NULL) {
- if (!does_collide_order((unsigned long)m, pagedir_order))
- break;
- eaten_memory = m;
- printk( "." );
- *eaten_memory = c;
- c = eaten_memory;
- }
+ /* Relocate colliding pages */
- if (!m) {
- printk("out of memory\n");
- ret = -ENOMEM;
- } else {
- pagedir_nosave =
- memcpy(m, old_pagedir, PAGE_SIZE << pagedir_order);
+ for_each_pb_page(pbpage, pblist) {
+ if (does_collide_order((unsigned long)pbpage, 0)) {
+ m = (void *)get_usable_page(GFP_ATOMIC | __GFP_COLD);
+ if (!m) {
+ error = -ENOMEM;
+ break;
+ }
+ memcpy(m, (void *)pbpage, PAGE_SIZE);
+ if (pbpage == pblist)
+ pblist = (struct pbe *)m;
+ else
+ tail->next = (struct pbe *)m;
+
+ free_page((unsigned long)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;
+
+ rel++;
+ }
+ tail = pbpage + PB_PAGE_SKIP;
+ }
+
+ if (error) {
+ printk("\nswsusp: Out of memory\n\n");
+ free_pagedir(pblist);
+ free_eaten_memory();
+ pblist = NULL;
}
+ else
+ printk("swsusp: Relocated %d pages\n", rel);
- c = eaten_memory;
- while (c) {
- printk(":");
- f = c;
- c = *c;
- free_pages((unsigned long)f, pagedir_order);
- }
- if (ret)
- return ret;
- printk("|\n");
- return check_pagedir();
+ return pblist;
}
/**
@@ -1149,76 +1208,150 @@
}
/**
- * swsusp_read_data - Read image pages from swap.
+ * data_read - Read image pages from swap.
*
* You do not need to check for overlaps, check_pagedir()
* already did that.
*/
-static int __init data_read(void)
+static int __init data_read(struct pbe *pblist)
{
struct pbe * p;
- int error;
- int i;
- int mod = nr_copy_pages / 100;
+ int error = 0;
+ int i = 0;
+ int mod = swsusp_info.image_pages / 100;
if (!mod)
mod = 1;
- if ((error = swsusp_pagedir_relocate()))
- return error;
+ printk("swsusp: Reading image data (%lu pages): ",
+ swsusp_info.image_pages);
+
+ for_each_pbe(p, pblist) {
+ if (!(i % mod))
+ printk("\b\b\b\b%3d%%", i / mod);
- printk( "Reading image data (%d pages): ", nr_copy_pages );
- for(i = 0, p = pagedir_nosave; i < nr_copy_pages && !error; i++, p++) {
- if (!(i%mod))
- printk( "\b\b\b\b%3d%%", i / mod );
error = bio_read_page(swp_offset(p->swap_address),
(void *)p->address);
+ if (error)
+ return error;
+
+ i++;
}
- printk(" %d done.\n",i);
+ printk("\b\b\b\bdone\n");
return error;
-
}
extern dev_t __init name_to_dev_t(const char *line);
-static int __init read_pagedir(void)
+/**
+ * read_pagedir - Read page backup list pages from swap, allocate
+ * memory for them and set up the list
+ *
+ * The list of PBEs that is created by this function may be freed
+ * using free_pagedir()
+ */
+
+static struct pbe * __init read_pagedir(void)
{
- unsigned long addr;
- int i, n = swsusp_info.pagedir_pages;
- int error = 0;
+ unsigned nr_pages = swsusp_info.image_pages;
+ unsigned num, i = 0;
+ struct pbe *pblist, *pbe, *p;
+ unsigned long offset;
+ int error;
- addr = __get_free_pages(GFP_ATOMIC, pagedir_order);
- if (!addr)
- return -ENOMEM;
- pagedir_nosave = (struct pbe *)addr;
+ if (!nr_pages)
+ return NULL;
+
+ printk("swsusp: Reading pagedir (%lu pages)\n",
+ swsusp_info.pagedir_pages);
- pr_debug("swsusp: Reading pagedir (%d Pages)\n",n);
+ pblist = (struct pbe *)get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
+ if (!pblist)
+ return NULL;
+
+ error = -EFAULT;
+ offset = swp_offset(swsusp_info.pagedir[i++]);
+ if (offset)
+ error = bio_read_page(offset, (void *)pblist);
+
+ if (error) {
+ free_page((unsigned long)pblist);
+ pblist = NULL;
+ }
+
+ for (pbe = pblist, num = PBES_PER_PAGE ; pbe && num < nr_pages ;
+ pbe = pbe->next, num += PBES_PER_PAGE) {
+ p = pbe;
+ pbe += PB_PAGE_SKIP;
+ do
+ p->next = p + 1;
+ while (p++ < pbe);
+ pbe->next = NULL;
+ error = -EFAULT;
+ p = (struct pbe *)get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
+ if (p)
+ offset = swp_offset(swsusp_info.pagedir[i++]);
- for (i = 0; i < n && !error; i++, addr += PAGE_SIZE) {
- unsigned long offset = swp_offset(swsusp_info.pagedir[i]);
if (offset)
- error = bio_read_page(offset, (void *)addr);
+ error = bio_read_page(offset, (void *)p);
+
+ if (error) {
+ if (p)
+ free_page((unsigned long)p);
+ }
else
- error = -EFAULT;
+ pbe->next = p;
}
- if (error)
- free_pages((unsigned long)pagedir_nosave, pagedir_order);
- return error;
+ if (pbe) {
+ for (num -= PBES_PER_PAGE - 1, p = pbe ; num < nr_pages ; p++,
num++)
+ p->next = p + 1;
+
+ p->next = NULL;
+ pr_debug("swsusp: Read %d pages, allocated %d PBEs\n", i, num);
+ error = (i != swsusp_info.pagedir_pages); /* a sanity check */
+ }
+ if (error) { /* if pbe is zero, error must be non-zero */
+ free_pagedir(pblist);
+ pblist = NULL;
+ pr_debug("swsusp: Reading pagedir failed\n");
+ }
+ return pblist;
}
+
static int __init read_suspend_image(void)
{
int error = 0;
+ struct pbe *p;
if ((error = check_sig()))
return error;
+
if ((error = check_header()))
return error;
- if ((error = read_pagedir()))
- return error;
- if ((error = data_read()))
- free_pages((unsigned long)pagedir_nosave, pagedir_order);
+
+ if(!(p = read_pagedir()))
+ return -EFAULT;
+
+ if(!(pagedir_nosave = swsusp_pagedir_relocate(p)))
+ return -ENOMEM;
+
+ /* Allocate memory for the image and read the data from swap */
+
+ error = check_pagedir(pagedir_nosave);
+ free_eaten_memory();
+ if (!error)
+ error = data_read(pagedir_nosave);
+
+ if (error) { /* We fail cleanly */
+ for_each_pbe(p, pagedir_nosave)
+ if (p->address) {
+ free_page(p->address);
+ p->address = 0UL;
+ }
+ free_pagedir(pagedir_nosave);
+ }
return error;
}
--
- Would you tell me, please, which way I ought to go from here?
- That depends a good deal on where you want to get to.
-- Lewis Carroll "Alice's Adventures in Wonderland"
-
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