Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758393Ab0BDTcg (ORCPT ); Thu, 4 Feb 2010 14:32:36 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:45451 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758231Ab0BDTcb (ORCPT ); Thu, 4 Feb 2010 14:32:31 -0500 From: "Rafael J. Wysocki" To: Andrew Morton Subject: Re: [RFC][PATCH] PM: disable nonboot cpus before suspending devices Date: Thu, 4 Feb 2010 20:33:01 +0100 User-Agent: KMail/1.12.4 (Linux/2.6.33-rc6-rjw; KDE/4.3.5; x86_64; ; ) Cc: Sebastian Ott , linux-pm@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Benjamin Herrenschmidt , KOSAKI Motohiro References: <20100203172147.2411966d.akpm@linux-foundation.org> <20100203174150.192a417a.akpm@linux-foundation.org> In-Reply-To: <20100203174150.192a417a.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <201002042033.01192.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8317 Lines: 255 On Thursday 04 February 2010, Andrew Morton wrote: > On Wed, 3 Feb 2010 17:21:47 -0800 Andrew Morton wrote: > > > On Thu, 4 Feb 2010 01:50:26 +0100 "Rafael J. Wysocki" wrote: > > > > > --- linux-2.6.orig/mm/page_alloc.c > > > +++ linux-2.6/mm/page_alloc.c > > > @@ -76,6 +76,30 @@ unsigned long totalreserve_pages __read_ > > > int percpu_pagelist_fraction; > > > gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK; > > > > > > +/* > > > + * The following functions are used by the suspend/hibernate code to temporarily > > > + * change gfp_allowed_mask in order to avoid using I/O during memory allocations > > > + * while devices are suspended. To avoid races with the suspend/hibernate code, > > > + * they should always be called with pm_mutex held (gfp_allowed_mask also should > > > + * 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) > > > +{ > > > + WARN_ON(!mutex_is_locked(&pm_mutex)); > > > + gfp_allowed_mask = mask; > > > +} > > > + > > > +gfp_t clear_gfp_allowed_mask(gfp_t mask) > > > +{ > > > + gfp_t ret = gfp_allowed_mask; > > > + > > > + WARN_ON(!mutex_is_locked(&pm_mutex)); > > > + gfp_allowed_mask &= ~mask; > > > + return ret; > > > +} > > > > Maybe put an ifdef CONFIG_foo around these so they don't get included > > when they're unneeded? > > > > I guess this: > > mm/built-in.o: In function `clear_gfp_allowed_mask': > : undefined reference to `pm_mutex' > mm/built-in.o: In function `set_gfp_allowed_mask': > : undefined reference to `pm_mutex' > > kinda answers my question. Sorry about that. I tend to forget about test-compiling with CONFIG_PM unset. The one below shouldn't have this issue. Rafael --- From: Rafael J. Wysocki Subject: MM / PM: Force GFP_NOIO during suspend/hibernation and resume (rev. 3) There are quite a few GFP_KERNEL memory allocations made during suspend/hibernation and resume that may cause the system to hang, because the I/O operations they depend on cannot be completed due to the underlying devices being suspended. Mitigate this problem by clearing the __GFP_IO and __GFP_FS bits in gfp_allowed_mask before suspend/hibernation and restoring the original values of these bits in gfp_allowed_mask durig the subsequent resume. Signed-off-by: Rafael J. Wysocki Reported-by: Maxim Levitsky --- include/linux/gfp.h | 7 +++---- init/main.c | 2 +- kernel/power/hibernate.c | 9 +++++++++ kernel/power/suspend.c | 3 +++ mm/page_alloc.c | 26 ++++++++++++++++++++++++++ 5 files changed, 42 insertions(+), 5 deletions(-) Index: linux-2.6/include/linux/gfp.h =================================================================== --- linux-2.6.orig/include/linux/gfp.h +++ linux-2.6/include/linux/gfp.h @@ -83,6 +83,7 @@ struct vm_area_struct; #define GFP_HIGHUSER_MOVABLE (__GFP_WAIT | __GFP_IO | __GFP_FS | \ __GFP_HARDWALL | __GFP_HIGHMEM | \ __GFP_MOVABLE) +#define GFP_IOFS (__GFP_IO | __GFP_FS) #ifdef CONFIG_NUMA #define GFP_THISNODE (__GFP_THISNODE | __GFP_NOWARN | __GFP_NORETRY) @@ -337,9 +338,7 @@ void drain_local_pages(void *dummy); extern gfp_t gfp_allowed_mask; -static inline void set_gfp_allowed_mask(gfp_t mask) -{ - gfp_allowed_mask = mask; -} +extern void set_gfp_allowed_mask(gfp_t mask); +extern gfp_t clear_gfp_allowed_mask(gfp_t mask); #endif /* __LINUX_GFP_H */ Index: linux-2.6/init/main.c =================================================================== --- linux-2.6.orig/init/main.c +++ linux-2.6/init/main.c @@ -601,7 +601,7 @@ asmlinkage void __init start_kernel(void local_irq_enable(); /* Interrupts are enabled now so all GFP allocations are safe. */ - set_gfp_allowed_mask(__GFP_BITS_MASK); + gfp_allowed_mask = __GFP_BITS_MASK; kmem_cache_init_late(); Index: linux-2.6/mm/page_alloc.c =================================================================== --- linux-2.6.orig/mm/page_alloc.c +++ linux-2.6/mm/page_alloc.c @@ -76,6 +76,32 @@ unsigned long totalreserve_pages __read_ int percpu_pagelist_fraction; gfp_t gfp_allowed_mask __read_mostly = GFP_BOOT_MASK; +#ifdef CONFIG_PM_SLEEP +/* + * The following functions are used by the suspend/hibernate code to temporarily + * change gfp_allowed_mask in order to avoid using I/O during memory allocations + * while devices are suspended. To avoid races with the suspend/hibernate code, + * they should always be called with pm_mutex held (gfp_allowed_mask also should + * 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) +{ + WARN_ON(!mutex_is_locked(&pm_mutex)); + gfp_allowed_mask = mask; +} + +gfp_t clear_gfp_allowed_mask(gfp_t mask) +{ + gfp_t ret = gfp_allowed_mask; + + WARN_ON(!mutex_is_locked(&pm_mutex)); + gfp_allowed_mask &= ~mask; + return ret; +} +#endif /* CONFIG_PM_SLEEP */ + #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE int pageblock_order __read_mostly; #endif Index: linux-2.6/kernel/power/hibernate.c =================================================================== --- linux-2.6.orig/kernel/power/hibernate.c +++ linux-2.6/kernel/power/hibernate.c @@ -323,6 +323,7 @@ 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) @@ -334,6 +335,7 @@ int hibernation_snapshot(int platform_mo goto Close; suspend_console(); + saved_mask = clear_gfp_allowed_mask(GFP_IOFS); error = dpm_suspend_start(PMSG_FREEZE); if (error) goto Recover_platform; @@ -351,6 +353,7 @@ int hibernation_snapshot(int platform_mo dpm_resume_end(in_suspend ? (error ? PMSG_RECOVER : PMSG_THAW) : PMSG_RESTORE); + set_gfp_allowed_mask(saved_mask); resume_console(); Close: platform_end(platform_mode); @@ -445,14 +448,17 @@ 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); 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); resume_console(); pm_restore_console(); return error; @@ -466,6 +472,7 @@ int hibernation_restore(int platform_mod int hibernation_platform_enter(void) { int error; + gfp_t saved_mask; if (!hibernation_ops) return -ENOSYS; @@ -481,6 +488,7 @@ 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) @@ -518,6 +526,7 @@ 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: Index: linux-2.6/kernel/power/suspend.c =================================================================== --- linux-2.6.orig/kernel/power/suspend.c +++ linux-2.6/kernel/power/suspend.c @@ -198,6 +198,7 @@ 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; @@ -208,6 +209,7 @@ int suspend_devices_and_enter(suspend_st goto Close; } suspend_console(); + saved_mask = clear_gfp_allowed_mask(GFP_IOFS); suspend_test_start(); error = dpm_suspend_start(PMSG_SUSPEND); if (error) { @@ -224,6 +226,7 @@ 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); 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@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/