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Date: Wed, 1 Dec 2010 01:38:53 +0100
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Hugh Dickins <hughd@...gle.com>
Cc: Ondrej Zary <linux@...nbow-software.org>,
Andrew Morton <akpm@...ux-foundation.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
Kernel development list <linux-kernel@...r.kernel.org>,
Balbir Singh <balbir@...ibm.com>
Subject: Re: 2.6.35.5: hibernation broken... AGAIN
On Wednesday, December 01, 2010, Rafael J. Wysocki wrote:
> On Tuesday, November 30, 2010, Hugh Dickins wrote:
> > On Sat, 27 Nov 2010, Rafael J. Wysocki wrote:
> > > On Saturday, November 27, 2010, Ondrej Zary wrote:
...
> >
> > Trivial point, I suppose, but it bothers me that PM is accumulating
> > wrappers around wrappers around gfp_allowed_mask. Looks like
> > clear_gfp_allowed_mask and set_gfp_allowed_mask (oddly asymmetrical)
> > were not really what we need. How about scrapping them, and putting
> > pm_restrict_gfp_mask() and pm_restore_gfp_mask() into page_alloc.c?
>
> Sure, that sounds like a good idea indeed.
Below is an updated patch in which I tried to address your comments.
I didn't find it very useful to couple pm_restore_gfp_mask() with the thawing
of tasks, but nevertheless I think all of the spots where it's needed are
covered now.
The patch has only been compile-tested for now, so caveat emptor.
Thanks,
Rafael
---
include/linux/gfp.h | 4 ++--
kernel/power/hibernate.c | 22 ++++++++++++----------
kernel/power/suspend.c | 5 ++---
kernel/power/user.c | 2 ++
mm/page_alloc.c | 18 +++++++++++-------
5 files changed, 29 insertions(+), 22 deletions(-)
Index: linux-2.6/kernel/power/hibernate.c
===================================================================
--- linux-2.6.orig/kernel/power/hibernate.c
+++ linux-2.6/kernel/power/hibernate.c
@@ -327,7 +327,6 @@ static int create_image(int platform_mod
int hibernation_snapshot(int platform_mode)
{
int error;
- gfp_t saved_mask;
error = platform_begin(platform_mode);
if (error)
@@ -339,7 +338,7 @@ int hibernation_snapshot(int platform_mo
goto Close;
suspend_console();
- saved_mask = clear_gfp_allowed_mask(GFP_IOFS);
+ pm_restrict_gfp_mask();
error = dpm_suspend_start(PMSG_FREEZE);
if (error)
goto Recover_platform;
@@ -348,7 +347,10 @@ int hibernation_snapshot(int platform_mo
goto Recover_platform;
error = create_image(platform_mode);
- /* Control returns here after successful restore */
+ /*
+ * Control returns here (1) after the image has been created or the
+ * image creation has failed and (2) after a successful restore.
+ */
Resume_devices:
/* We may need to release the preallocated image pages here. */
@@ -357,7 +359,10 @@ int hibernation_snapshot(int platform_mo
dpm_resume_end(in_suspend ?
(error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE);
- set_gfp_allowed_mask(saved_mask);
+
+ if (error || !in_suspend)
+ pm_restore_gfp_mask();
+
resume_console();
Close:
platform_end(platform_mode);
@@ -452,17 +457,16 @@ static int resume_target_kernel(bool pla
int hibernation_restore(int platform_mode)
{
int error;
- gfp_t saved_mask;
pm_prepare_console();
suspend_console();
- saved_mask = clear_gfp_allowed_mask(GFP_IOFS);
+ pm_restrict_gfp_mask();
error = dpm_suspend_start(PMSG_QUIESCE);
if (!error) {
error = resume_target_kernel(platform_mode);
dpm_resume_end(PMSG_RECOVER);
}
- set_gfp_allowed_mask(saved_mask);
+ pm_restore_gfp_mask();
resume_console();
pm_restore_console();
return error;
@@ -476,7 +480,6 @@ int hibernation_restore(int platform_mod
int hibernation_platform_enter(void)
{
int error;
- gfp_t saved_mask;
if (!hibernation_ops)
return -ENOSYS;
@@ -492,7 +495,6 @@ int hibernation_platform_enter(void)
entering_platform_hibernation = true;
suspend_console();
- saved_mask = clear_gfp_allowed_mask(GFP_IOFS);
error = dpm_suspend_start(PMSG_HIBERNATE);
if (error) {
if (hibernation_ops->recover)
@@ -536,7 +538,6 @@ int hibernation_platform_enter(void)
Resume_devices:
entering_platform_hibernation = false;
dpm_resume_end(PMSG_RESTORE);
- set_gfp_allowed_mask(saved_mask);
resume_console();
Close:
@@ -647,6 +648,7 @@ int hibernate(void)
if (!error)
power_down();
in_suspend = 0;
+ pm_restore_gfp_mask();
} else {
pr_debug("PM: Image restored successfully.\n");
}
Index: linux-2.6/kernel/power/user.c
===================================================================
--- linux-2.6.orig/kernel/power/user.c
+++ linux-2.6/kernel/power/user.c
@@ -263,6 +263,7 @@ static long snapshot_ioctl(struct file *
case SNAPSHOT_UNFREEZE:
if (!data->frozen || data->ready)
break;
+ pm_restore_gfp_mask();
thaw_processes();
usermodehelper_enable();
data->frozen = 0;
@@ -275,6 +276,7 @@ static long snapshot_ioctl(struct file *
error = -EPERM;
break;
}
+ pm_restore_gfp_mask();
error = hibernation_snapshot(data->platform_support);
if (!error)
error = put_user(in_suspend, (int __user *)arg);
Index: linux-2.6/mm/page_alloc.c
===================================================================
--- linux-2.6.orig/mm/page_alloc.c
+++ linux-2.6/mm/page_alloc.c
@@ -104,19 +104,23 @@ gfp_t gfp_allowed_mask __read_mostly = G
* only be modified with pm_mutex held, unless the suspend/hibernate code is
* guaranteed not to run in parallel with that modification).
*/
-void set_gfp_allowed_mask(gfp_t mask)
+
+static gfp_t saved_gfp_mask;
+
+void pm_restore_gfp_mask(void)
{
WARN_ON(!mutex_is_locked(&pm_mutex));
- gfp_allowed_mask = mask;
+ if (saved_gfp_mask) {
+ gfp_allowed_mask = saved_gfp_mask;
+ saved_gfp_mask = 0;
+ }
}
-gfp_t clear_gfp_allowed_mask(gfp_t mask)
+void pm_restrict_gfp_mask(void)
{
- gfp_t ret = gfp_allowed_mask;
-
WARN_ON(!mutex_is_locked(&pm_mutex));
- gfp_allowed_mask &= ~mask;
- return ret;
+ saved_gfp_mask = gfp_allowed_mask;
+ gfp_allowed_mask &= ~GFP_IOFS;
}
#endif /* CONFIG_PM_SLEEP */
Index: linux-2.6/include/linux/gfp.h
===================================================================
--- linux-2.6.orig/include/linux/gfp.h
+++ linux-2.6/include/linux/gfp.h
@@ -360,7 +360,7 @@ void drain_local_pages(void *dummy);
extern gfp_t gfp_allowed_mask;
-extern void set_gfp_allowed_mask(gfp_t mask);
-extern gfp_t clear_gfp_allowed_mask(gfp_t mask);
+extern void pm_restrict_gfp_mask(void);
+extern void pm_restore_gfp_mask(void);
#endif /* __LINUX_GFP_H */
Index: linux-2.6/kernel/power/suspend.c
===================================================================
--- linux-2.6.orig/kernel/power/suspend.c
+++ linux-2.6/kernel/power/suspend.c
@@ -197,7 +197,6 @@ static int suspend_enter(suspend_state_t
int suspend_devices_and_enter(suspend_state_t state)
{
int error;
- gfp_t saved_mask;
if (!suspend_ops)
return -ENOSYS;
@@ -208,7 +207,7 @@ int suspend_devices_and_enter(suspend_st
goto Close;
}
suspend_console();
- saved_mask = clear_gfp_allowed_mask(GFP_IOFS);
+ pm_restrict_gfp_mask();
suspend_test_start();
error = dpm_suspend_start(PMSG_SUSPEND);
if (error) {
@@ -225,7 +224,7 @@ int suspend_devices_and_enter(suspend_st
suspend_test_start();
dpm_resume_end(PMSG_RESUME);
suspend_test_finish("resume devices");
- set_gfp_allowed_mask(saved_mask);
+ pm_restore_gfp_mask();
resume_console();
Close:
if (suspend_ops->end)
--
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