Re: [PATCH] swsusp: rework swsusp_suspend
From: Rafael J. Wysocki
Date: Tue Nov 01 2005 - 12:13:20 EST
Hi,
On Monday, 31 of October 2005 23:04, Pavel Machek wrote:
> Hi!
>
> > The following patch makes only the functions in swsusp.c call functions in
> > snapshot.c and not both ways. It also moves the check for available swap
> > out of swsusp_suspend() which is necessary for separating the swap-handling
> > functions in swsusp from the core code.
>
> Moving highmem handling code is not neccessary for this goal, right?
No, it is a side-effect.
> Please keep it in place.
OK (although I don't see why you are insisting on this).
> (You being x86-64 person, I can understand you don't want it in
> snapshot.c ;-)
This isn't related to my hardware preferences. ;-)
The highmem-handling functions have nothing to do with the snapshot
functionality, because the highmem is _really_ saved _before_ creating
the snapshot and restored _after_ it has beed created.
Clearly restore_highmem() is only called from swsusp_suspend()
and swsusp_resume() which are in swsusp.c. If CONFIG_HIGHMEM
is unset, it is defined as a non-static empty function which bloats the kernel
as Ingo Oeser has already noticed. Therefore if CONFIG_HIGHMEM
is unset, restore_highmem() should be declared as a static empty function in
swsusp.c (this declaration should not be placed in power.h as it causes some
compiler warnings to appear for files that do not use restore_highmem()).
By analogy it should be defined as a static function is CONFIG_HIGHMEM
is set either.
OTOH save_highmem() is actually symmetrical to restore_highmem(),
so it should be called from the same function from which restore_highmem()
is called, and this function is swsusp_suspend() (the call to restore_highmem()
from swsusp_resume() is unnecessary, but you refused to let it go).
Anyway the appended patch contains only changes that you have
already agreed with, except for the "#ifdef CONFIG_HIGHMEM" thing in swsusp.c
which originally was in snapshot.c (and bloated the kernel).
Greetings,
Rafael
Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
kernel/power/power.h | 2
kernel/power/snapshot.c | 102 ------------------------------
kernel/power/swsusp.c | 158 ++++++++++++++++++++++++++++++++++++++----------
3 files changed, 128 insertions(+), 134 deletions(-)
Index: linux-2.6.14-git4/kernel/power/snapshot.c
===================================================================
--- linux-2.6.14-git4.orig/kernel/power/snapshot.c 2005-11-01 14:04:41.000000000 +0100
+++ linux-2.6.14-git4/kernel/power/snapshot.c 2005-11-01 14:14:01.000000000 +0100
@@ -88,8 +88,7 @@
return 0;
}
-
-static int save_highmem(void)
+int save_highmem(void)
{
struct zone *zone;
int res = 0;
@@ -120,11 +119,7 @@
}
return 0;
}
-#else
-static int save_highmem(void) { return 0; }
-int restore_highmem(void) { return 0; }
-#endif /* CONFIG_HIGHMEM */
-
+#endif
static int pfn_is_nosave(unsigned long pfn)
{
@@ -383,11 +378,6 @@
unsigned nr_pages;
pr_debug("swsusp: critical section: \n");
- if (save_highmem()) {
- printk(KERN_CRIT "swsusp: Not enough free pages for highmem\n");
- restore_highmem();
- return -ENOMEM;
- }
drain_local_pages();
nr_pages = count_data_pages();
@@ -407,11 +397,6 @@
return -ENOMEM;
}
- if (!enough_swap(nr_pages)) {
- printk(KERN_ERR "swsusp: Not enough free swap\n");
- return -ENOSPC;
- }
-
pagedir_nosave = swsusp_alloc(nr_pages);
if (!pagedir_nosave)
return -ENOMEM;
Index: linux-2.6.14-git4/kernel/power/swsusp.c
===================================================================
--- linux-2.6.14-git4.orig/kernel/power/swsusp.c 2005-11-01 14:04:41.000000000 +0100
+++ linux-2.6.14-git4/kernel/power/swsusp.c 2005-11-01 14:12:42.000000000 +0100
@@ -73,6 +73,14 @@
#include "power.h"
+#ifdef CONFIG_HIGHMEM
+int save_highmem(void);
+int restore_highmem(void);
+#else
+static int save_highmem(void) { return 0; }
+static int restore_highmem(void) { return 0; }
+#endif
+
#define CIPHER "aes"
#define MAXKEY 32
#define MAXIV 32
@@ -507,6 +515,26 @@
}
/**
+ * enough_swap - Make sure we have enough swap to save the image.
+ *
+ * Returns TRUE or FALSE after checking the total amount of swap
+ * space avaiable.
+ *
+ * FIXME: si_swapinfo(&i) returns all swap devices information.
+ * We should only consider resume_device.
+ */
+
+static int enough_swap(unsigned long nr_pages)
+{
+ struct sysinfo i;
+
+ si_swapinfo(&i);
+ pr_debug("swsusp: available swap: %lu pages\n", i.freeswap);
+ return i.freeswap > (nr_pages + PAGES_FOR_IO +
+ (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
+}
+
+/**
* write_suspend_image - Write entire image and metadata.
*
*/
@@ -514,6 +542,11 @@
{
int error;
+ if (!enough_swap(nr_copy_pages)) {
+ printk(KERN_ERR "swsusp: Not enough free swap\n");
+ return -ENOSPC;
+ }
+
init_header();
if ((error = data_write()))
goto FreeData;
@@ -533,27 +566,6 @@
goto Done;
}
-/**
- * enough_swap - Make sure we have enough swap to save the image.
- *
- * Returns TRUE or FALSE after checking the total amount of swap
- * space avaiable.
- *
- * FIXME: si_swapinfo(&i) returns all swap devices information.
- * We should only consider resume_device.
- */
-
-int enough_swap(unsigned nr_pages)
-{
- struct sysinfo i;
-
- si_swapinfo(&i);
- pr_debug("swsusp: available swap: %lu pages\n", i.freeswap);
- return i.freeswap > (nr_pages + PAGES_FOR_IO +
- (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
-}
-
-
/* It is important _NOT_ to umount filesystems at this point. We want
* them synced (in case something goes wrong) but we DO not want to mark
* filesystem clean: it is not. (And it does not matter, if we resume
@@ -563,12 +575,15 @@
{
int error;
+ if ((error = swsusp_swap_check())) {
+ printk(KERN_ERR "swsusp: cannot find swap device, try swapon -a.\n");
+ return error;
+ }
lock_swapdevices();
error = write_suspend_image();
/* This will unlock ignored swap devices since writing is finished */
lock_swapdevices();
return error;
-
}
@@ -576,6 +591,7 @@
int swsusp_suspend(void)
{
int error;
+
if ((error = arch_prepare_suspend()))
return error;
local_irq_disable();
@@ -587,15 +603,12 @@
*/
if ((error = device_power_down(PMSG_FREEZE))) {
printk(KERN_ERR "Some devices failed to power down, aborting suspend\n");
- local_irq_enable();
- return error;
+ goto Enable_irqs;
}
- if ((error = swsusp_swap_check())) {
- printk(KERN_ERR "swsusp: cannot find swap device, try swapon -a.\n");
- device_power_up();
- local_irq_enable();
- return error;
+ if ((error = save_highmem())) {
+ printk(KERN_ERR "swsusp: Not enough free pages for highmem\n");
+ goto Restore_highmem;
}
save_processor_state();
@@ -603,8 +616,10 @@
printk(KERN_ERR "Error %d suspending\n", error);
/* Restore control flow magically appears here */
restore_processor_state();
+Restore_highmem:
restore_highmem();
device_power_up();
+Enable_irqs:
local_irq_enable();
return error;
}
@@ -895,7 +910,7 @@
* Reset swap signature now.
*/
error = bio_write_page(0, &swsusp_header);
- } else {
+ } else {
return -EINVAL;
}
if (!error)
Index: linux-2.6.14-git4/kernel/power/power.h
===================================================================
--- linux-2.6.14-git4.orig/kernel/power/power.h 2005-11-01 14:04:41.000000000 +0100
+++ linux-2.6.14-git4/kernel/power/power.h 2005-11-01 14:08:24.000000000 +0100
@@ -65,8 +65,6 @@
extern asmlinkage int swsusp_arch_suspend(void);
extern asmlinkage int swsusp_arch_resume(void);
-extern int restore_highmem(void);
extern struct pbe * alloc_pagedir(unsigned nr_pages);
extern void create_pbe_list(struct pbe *pblist, unsigned nr_pages);
extern void swsusp_free(void);
-extern int enough_swap(unsigned nr_pages);
-
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