Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751768AbXE2WTQ (ORCPT ); Tue, 29 May 2007 18:19:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750823AbXE2WTE (ORCPT ); Tue, 29 May 2007 18:19:04 -0400 Received: from ogre.sisk.pl ([217.79.144.158]:39627 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750803AbXE2WTB (ORCPT ); Tue, 29 May 2007 18:19:01 -0400 From: "Rafael J. Wysocki" To: Alan Stern , Pavel Machek Subject: Re: [RFC][PATCH -mm 1/3] PM: Hibernation and suspend notifiers Date: Wed, 30 May 2007 00:24:31 +0200 User-Agent: KMail/1.9.5 Cc: pm list , LKML , Matthew Garrett , Nigel Cunningham , Oliver Neukum References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200705300024.32455.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 13929 Lines: 387 On Monday, 28 May 2007 17:56, Alan Stern wrote: > On Sun, 27 May 2007, Rafael J. Wysocki wrote: > > > From: Rafael J. Wysocki > > > > Make it possible to register hibernation and suspend notifiers, so that > > subsystems can perform hibernation-related or suspend-related operations that > > should not be carried out by device drivers' .suspend() and .resume() routines. > > > +static DEFINE_MUTEX(pm_notifier_lock); > > + > > +static RAW_NOTIFIER_HEAD(pm_chain); > > Is there any particular reason you chose to use a RAW_NOTIFIER_HEAD > with an explicit mutex instead of using a BLOCKING_NOTIFIER_HEAD? Yes, this makes the patch simpler. I have also followed the Pavel's suggestion to limit the nubmer of events. Please have a look at the updated version of the patch (appended). Greetings, Rafael --- From: Rafael J. Wysocki Make it possible to register hibernation and suspend notifiers, so that subsystems can perform hibernation-related or suspend-related operations that should not be carried out by device drivers' .suspend() and .resume() routines. Signed-off-by: Rafael J. Wysocki Documentation/power/notifiers.txt | 57 ++++++++++++++++++++++++++++++++++++++ include/linux/notifier.h | 8 +++++ include/linux/suspend.h | 37 ++++++++++++++++++++++-- kernel/power/disk.c | 24 ++++++++++++---- kernel/power/main.c | 14 +++++++++ kernel/power/power.h | 10 ++++++ kernel/power/user.c | 11 +++++-- 7 files changed, 150 insertions(+), 11 deletions(-) Index: linux-2.6.22-rc3/include/linux/suspend.h =================================================================== --- linux-2.6.22-rc3.orig/include/linux/suspend.h 2007-05-27 19:57:21.000000000 +0200 +++ linux-2.6.22-rc3/include/linux/suspend.h 2007-05-29 22:52:24.000000000 +0200 @@ -54,7 +54,8 @@ struct hibernation_ops { void (*restore_cleanup)(void); }; -#if defined(CONFIG_PM) && defined(CONFIG_SOFTWARE_SUSPEND) +#ifdef CONFIG_PM +#ifdef CONFIG_SOFTWARE_SUSPEND /* kernel/power/snapshot.c */ extern void __register_nosave_region(unsigned long b, unsigned long e, int km); static inline void register_nosave_region(unsigned long b, unsigned long e) @@ -72,7 +73,7 @@ extern unsigned long get_safe_page(gfp_t extern void hibernation_set_ops(struct hibernation_ops *ops); extern int hibernate(void); -#else +#else /* CONFIG_SOFTWARE_SUSPEND */ static inline void register_nosave_region(unsigned long b, unsigned long e) {} static inline void register_nosave_region_late(unsigned long b, unsigned long e) {} static inline int swsusp_page_is_forbidden(struct page *p) { return 0; } @@ -81,7 +82,7 @@ static inline void swsusp_unset_page_fre static inline void hibernation_set_ops(struct hibernation_ops *ops) {} static inline int hibernate(void) { return -ENOSYS; } -#endif /* defined(CONFIG_PM) && defined(CONFIG_SOFTWARE_SUSPEND) */ +#endif /* CONFIG_SOFTWARE_SUSPEND */ void save_processor_state(void); void restore_processor_state(void); @@ -89,4 +90,34 @@ struct saved_context; void __save_processor_state(struct saved_context *ctxt); void __restore_processor_state(struct saved_context *ctxt); +/* kernel/power/main.c */ +extern struct blocking_notifier_head pm_chain_head; + +static inline int register_pm_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_register(&pm_chain_head, nb); +} + +static inline int unregister_pm_notifier(struct notifier_block *nb) +{ + return blocking_notifier_chain_unregister(&pm_chain_head, nb); +} + +#define pm_notifier(fn, pri) { \ + static struct notifier_block fn##_nb = \ + { .notifier_call = fn, .priority = pri }; \ + register_pm_notifier(&fn##_nb); \ +} +#else /* CONFIG_PM */ +static inline int register_pm_notifier(struct notifier_block *nb) { + return 0; +} + +static inline int unregister_pm_notifier(struct notifier_block *nb) { + return 0; +} + +#define pm_notifier(fn, pri) do { (void)(fn); } while (0) +#endif /* CONFIG_PM */ + #endif /* _LINUX_SWSUSP_H */ Index: linux-2.6.22-rc3/kernel/power/power.h =================================================================== --- linux-2.6.22-rc3.orig/kernel/power/power.h 2007-05-27 19:57:21.000000000 +0200 +++ linux-2.6.22-rc3/kernel/power/power.h 2007-05-29 22:53:12.000000000 +0200 @@ -173,5 +173,15 @@ extern void swsusp_close(void); extern int suspend_enter(suspend_state_t state); struct timeval; +/* kernel/power/swsusp.c */ extern void swsusp_show_speed(struct timeval *, struct timeval *, unsigned int, char *); + +/* kernel/power/main.c */ +extern struct blocking_notifier_head pm_chain_head; + +static inline int pm_notifier_call_chain(unsigned long val) +{ + return (blocking_notifier_call_chain(&pm_chain_head, val, NULL) + == NOTIFY_BAD) ? -EINVAL : 0; +} Index: linux-2.6.22-rc3/include/linux/notifier.h =================================================================== --- linux-2.6.22-rc3.orig/include/linux/notifier.h 2007-05-27 19:57:21.000000000 +0200 +++ linux-2.6.22-rc3/include/linux/notifier.h 2007-05-29 22:58:13.000000000 +0200 @@ -209,5 +209,13 @@ extern int __srcu_notifier_call_chain(st #define CPU_DOWN_FAILED_FROZEN (CPU_DOWN_FAILED | CPU_TASKS_FROZEN) #define CPU_DEAD_FROZEN (CPU_DEAD | CPU_TASKS_FROZEN) +/* Hibernation and suspend events */ +#define PM_PRE_FREEZE 0x0001 /* Going to freeze tasks */ +#define PM_POST_THAW 0x0002 /* Tasks have just been thawed */ +#define PM_HIBERNATION_PREPARE 0x0003 /* Tasks frozen, going to hibernate */ +#define PM_POST_HIBERNATION 0x0004 /* Hibernation finished, thawing tasks */ +#define PM_SUSPEND_PREPARE 0x0005 /* Going to suspend the system */ +#define PM_POST_SUSPEND 0x0006 /* Suspend finished */ + #endif /* __KERNEL__ */ #endif /* _LINUX_NOTIFIER_H */ Index: linux-2.6.22-rc3/kernel/power/disk.c =================================================================== --- linux-2.6.22-rc3.orig/kernel/power/disk.c 2007-05-27 19:57:21.000000000 +0200 +++ linux-2.6.22-rc3/kernel/power/disk.c 2007-05-30 00:26:41.000000000 +0200 @@ -130,10 +130,14 @@ int hibernation_snapshot(int platform_mo { int error; + error = pm_notifier_call_chain(PM_HIBERNATION_PREPARE); + if (error) + return error; + /* Free memory before shutting down devices. */ error = swsusp_shrink_memory(); if (error) - return error; + goto Finish; suspend_console(); error = device_suspend(PMSG_FREEZE); @@ -161,6 +165,8 @@ int hibernation_snapshot(int platform_mo device_resume(); Resume_console: resume_console(); + Finish: + pm_notifier_call_chain(PM_POST_HIBERNATION); return error; } @@ -259,12 +265,17 @@ static void unprepare_processes(void) { thaw_processes(); pm_restore_console(); + pm_notifier_call_chain(PM_POST_THAW); } static int prepare_processes(void) { int error = 0; + error = pm_notifier_call_chain(PM_PRE_FREEZE); + if (error) + return error; + pm_prepare_console(); if (freeze_processes()) { error = -EBUSY; @@ -281,9 +292,12 @@ int hibernate(void) { int error; + mutex_lock(&pm_mutex); /* The snapshot device should not be opened while we're running */ - if (!atomic_add_unless(&snapshot_device_available, -1, 0)) - return -EBUSY; + if (!atomic_add_unless(&snapshot_device_available, -1, 0)) { + error = -EBUSY; + goto Unlock; + } /* Allocate memory management structures */ error = create_basic_memory_bitmaps(); @@ -294,7 +308,6 @@ int hibernate(void) if (error) goto Finish; - mutex_lock(&pm_mutex); if (hibernation_mode == HIBERNATION_TESTPROC) { printk("swsusp debug: Waiting for 5 seconds.\n"); mdelay(5000); @@ -316,12 +329,13 @@ int hibernate(void) swsusp_free(); } Thaw: - mutex_unlock(&pm_mutex); unprepare_processes(); Finish: free_basic_memory_bitmaps(); Exit: atomic_inc(&snapshot_device_available); + Unlock: + mutex_unlock(&pm_mutex); return error; } Index: linux-2.6.22-rc3/kernel/power/main.c =================================================================== --- linux-2.6.22-rc3.orig/kernel/power/main.c 2007-05-27 19:57:21.000000000 +0200 +++ linux-2.6.22-rc3/kernel/power/main.c 2007-05-29 22:54:30.000000000 +0200 @@ -24,6 +24,8 @@ #include "power.h" +BLOCKING_NOTIFIER_HEAD(pm_chain_head); + /*This is just an arbitrary number */ #define FREE_PAGE_NUMBER (100) @@ -82,6 +84,10 @@ static int suspend_prepare(suspend_state if (!pm_ops || !pm_ops->enter) return -EPERM; + error = pm_notifier_call_chain(PM_PRE_FREEZE); + if (error) + return error; + pm_prepare_console(); if (freeze_processes()) { @@ -89,6 +95,10 @@ static int suspend_prepare(suspend_state goto Thaw; } + error = pm_notifier_call_chain(PM_SUSPEND_PREPARE); + if (error) + return error; + if ((free_pages = global_page_state(NR_FREE_PAGES)) < FREE_PAGE_NUMBER) { pr_debug("PM: free some memory\n"); @@ -121,9 +131,11 @@ static int suspend_prepare(suspend_state device_resume(); Resume_console: resume_console(); + pm_notifier_call_chain(PM_POST_SUSPEND); Thaw: thaw_processes(); pm_restore_console(); + pm_notifier_call_chain(PM_POST_THAW); return error; } @@ -173,8 +185,10 @@ static void suspend_finish(suspend_state pm_finish(state); device_resume(); resume_console(); + pm_notifier_call_chain(PM_POST_SUSPEND); thaw_processes(); pm_restore_console(); + pm_notifier_call_chain(PM_POST_THAW); } Index: linux-2.6.22-rc3/kernel/power/user.c =================================================================== --- linux-2.6.22-rc3.orig/kernel/power/user.c 2007-05-27 19:57:21.000000000 +0200 +++ linux-2.6.22-rc3/kernel/power/user.c 2007-05-29 22:35:08.000000000 +0200 @@ -149,9 +149,13 @@ static int snapshot_ioctl(struct inode * if (data->frozen) break; mutex_lock(&pm_mutex); - if (freeze_processes()) { - thaw_processes(); - error = -EBUSY; + error = pm_notifier_call_chain(PM_PRE_FREEZE); + if (!error) { + error = freeze_processes(); + if (error) { + thaw_processes(); + pm_notifier_call_chain(PM_POST_THAW); + } } mutex_unlock(&pm_mutex); if (!error) @@ -163,6 +167,7 @@ static int snapshot_ioctl(struct inode * break; mutex_lock(&pm_mutex); thaw_processes(); + pm_notifier_call_chain(PM_POST_THAW); mutex_unlock(&pm_mutex); data->frozen = 0; break; Index: linux-2.6.22-rc3/Documentation/power/notifiers.txt =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-2.6.22-rc3/Documentation/power/notifiers.txt 2007-05-29 23:04:20.000000000 +0200 @@ -0,0 +1,57 @@ +Suspend notifiers + (C) 2007 Rafael J. Wysocki , GPL + +There are some operations that device drivers may want to carry out in their +.suspend() routines, but shouldn't, because they can cause the hibernation or +suspend to fail. For example, a driver may want to allocate a substantial amount +of memory (like 50 MB) in .suspend(), but that shouldn't be done after the +swsusp's memory shrinker has run. + +Also, there may be some operations, that subsystems want to carry out before a +hibernation/suspend or after a restore/resume, requiring the system to be fully +functional, so the drivers' .suspend() and .resume() routines are not suitable +for this purpose. For example, device drivers may want to upload firmware to +their devices after a restore from a hibernation image, but they cannot do it by +calling request_firmware() from their .resume() routines (user land processes +are frozen at this point). The solution may be to load the firmware into +memory before processes are frozen and upload it from there in the .resume() +routine. Of course, a hibernation notifier may be used for this purpose. + +The subsystems that have such needs can register suspend notifiers that will be +called upon the following events by the suspend core: + +PM_PRE_FREEZE The system is going to hibernate or suspend, tasks will + be frozen immediately + +PM_POST_THAW Tasks have just been thawed after a resume or restore + from a hibernation image + +PM_HIBERNATION_PREPARE The system is preparing for hibernation. Tasks have + been frozen, memory is going to be freed and devices + are going to be suspended. + +PM_POST_HIBERNATION The system memory state has been restored from a + hibernation image or an error occured during the + hibernation. Device drivers' .resume() callbacks have + been executed, tasks will be thawed immediately. + +PM_SUSPEND_PREPARE The system is preparing for a suspend. Tasks have been + frozen, devices are going to be suspended. + +PM_POST_SUSPEND The system has just resumed or an error occured during + the suspend. Device drivers' .resume() callbacks have + been executed, tasks will be thawed immediately. + +It is generally assumed that whatever the notifiers do for PM_PRE_FREEZE, +should be undone for PM_POST_THAW. Moreover, what is done for +PM_HIBERNATION_PREPARE, should be undone for PM_POST_HIBERNATION (eg. if memory +is allocated for PM_HIBERNATION_PREPARE, it should be freed for +PM_POST_HIBERNATION). Analogously, operations performed for PM_SUSPEND_PREPARE +should be reversed for PM_POST_SUSPEND. + +The hibernation and suspend notifiers are called with pm_mutex held. They are +defined in the usual way, but their last argument is meaningless (it is always +NULL). To register and/or unregister a suspend notifier use the functions +register_pm_notifier() and unregister_pm_notifier(), respectively, defined in +include/linux/suspend.h . If you don't need to unregister the notifier, you can +also use the pm_notifier() macro defined in include/linux/suspend.h . - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/