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Date: Tue, 30 Nov 2010 17:21:39 -0800 (PST) From: Hugh Dickins <hughd@...gle.com> To: "Rafael J. Wysocki" <rjw@...k.pl> 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 Wed, 1 Dec 2010, Rafael J. Wysocki wrote: > 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. So far as I can see, yes, they are: I'm still a bit worried about future changes leaving the wrong gfp mask behind by mistake; but I trust you more than I trust me on that, so you can add my Acked-by: Hugh Dickins <hughd@...gle.com> when it comes to sending in the patch. Thanks, Hugh > > 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) > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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