From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nicholas Piggin Subject: [PATCH v2 3/5] kernel/cpu: Allow non-zero CPU to be primary for suspend / kexec freeze Date: Thu, 11 Apr 2019 13:34:46 +1000 Message-ID: <20190411033448.20842-4-npiggin@gmail.com> References: <20190411033448.20842-1-npiggin@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190411033448.20842-1-npiggin@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Thomas Gleixner , Frederic Weisbecker Cc: Nicholas Piggin , Ingo Molnar , Peter Zijlstra , "Rafael J . Wysocki" , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org List-Id: linux-arch.vger.kernel.org This patch provides an arch option, ARCH_SUSPEND_NONZERO_CPU, to opt-in to allowing suspend to occur on one of the housekeeping CPUs rather than hardcoded CPU0. This will allow CPU0 to be a nohz_full CPU with a later change. It may be possible for platforms with hardware/firmware restrictions on suspend/wake effectively support this by handing off the final stage to CPU0 when kernel housekeeping is no longer required. Another option is to make housekeeping / nohz_full mask dynamic at runtime, but the complexity could not be justified at this time. Signed-off-by: Nicholas Piggin --- arch/powerpc/Kconfig | 4 ++++ include/linux/cpu.h | 7 ++++++- kernel/cpu.c | 10 +++++++++- kernel/power/Kconfig | 9 +++++++++ 4 files changed, 28 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 2d0be82c3061..bc98b0e37a10 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -318,6 +318,10 @@ config ARCH_SUSPEND_POSSIBLE (PPC_85xx && !PPC_E500MC) || PPC_86xx || PPC_PSERIES \ || 44x || 40x +config ARCH_SUSPEND_NONZERO_CPU + def_bool y + depends on PPC_POWERNV || PPC_PSERIES + config PPC_DCR_NATIVE bool diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 563e697e7779..dd3813959d62 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -140,7 +140,12 @@ extern void enable_nonboot_cpus(void); static inline int suspend_disable_secondary_cpus(void) { - return freeze_secondary_cpus(0); + int cpu = 0; + + if (IS_ENABLED(CONFIG_PM_SLEEP_SMP_NONZERO_CPU)) + cpu = -1; + + return freeze_secondary_cpus(cpu); } static inline void suspend_enable_secondary_cpus(void) { diff --git a/kernel/cpu.c b/kernel/cpu.c index 6754f3ecfd94..d1bf6e2b4752 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include #include @@ -1199,8 +1200,15 @@ int freeze_secondary_cpus(int primary) int cpu, error = 0; cpu_maps_update_begin(); - if (!cpu_online(primary)) + if (primary == -1) { primary = cpumask_first(cpu_online_mask); + if (!housekeeping_cpu(primary, HK_FLAG_TIMER)) + primary = housekeeping_any_cpu(HK_FLAG_TIMER); + } else { + if (!cpu_online(primary)) + primary = cpumask_first(cpu_online_mask); + } + /* * We take down all of the non-boot CPUs in one shot to avoid races * with the userspace trying to use the CPU hotplug at the same time diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index f8fe57d1022e..9bbaaab14b36 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -114,6 +114,15 @@ config PM_SLEEP_SMP depends on PM_SLEEP select HOTPLUG_CPU +config PM_SLEEP_SMP_NONZERO_CPU + def_bool y + depends on PM_SLEEP_SMP + depends on ARCH_SUSPEND_NONZERO_CPU + ---help--- + If an arch can suspend (for suspend, hibernate, kexec, etc) on a + non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This + will allow nohz_full mask to include CPU0. + config PM_AUTOSLEEP bool "Opportunistic sleep" depends on PM_SLEEP -- 2.20.1 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f193.google.com ([209.85.215.193]:43956 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726230AbfDKDfR (ORCPT ); Wed, 10 Apr 2019 23:35:17 -0400 From: Nicholas Piggin Subject: [PATCH v2 3/5] kernel/cpu: Allow non-zero CPU to be primary for suspend / kexec freeze Date: Thu, 11 Apr 2019 13:34:46 +1000 Message-ID: <20190411033448.20842-4-npiggin@gmail.com> In-Reply-To: <20190411033448.20842-1-npiggin@gmail.com> References: <20190411033448.20842-1-npiggin@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-arch-owner@vger.kernel.org List-ID: To: Thomas Gleixner , Frederic Weisbecker Cc: Nicholas Piggin , Ingo Molnar , Peter Zijlstra , "Rafael J . Wysocki" , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Message-ID: <20190411033446.YYc7Q_Nm6EvTncXAEWOE3zhYW0-HUVZri0NoPQfevPs@z> This patch provides an arch option, ARCH_SUSPEND_NONZERO_CPU, to opt-in to allowing suspend to occur on one of the housekeeping CPUs rather than hardcoded CPU0. This will allow CPU0 to be a nohz_full CPU with a later change. It may be possible for platforms with hardware/firmware restrictions on suspend/wake effectively support this by handing off the final stage to CPU0 when kernel housekeeping is no longer required. Another option is to make housekeeping / nohz_full mask dynamic at runtime, but the complexity could not be justified at this time. Signed-off-by: Nicholas Piggin --- arch/powerpc/Kconfig | 4 ++++ include/linux/cpu.h | 7 ++++++- kernel/cpu.c | 10 +++++++++- kernel/power/Kconfig | 9 +++++++++ 4 files changed, 28 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 2d0be82c3061..bc98b0e37a10 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -318,6 +318,10 @@ config ARCH_SUSPEND_POSSIBLE (PPC_85xx && !PPC_E500MC) || PPC_86xx || PPC_PSERIES \ || 44x || 40x +config ARCH_SUSPEND_NONZERO_CPU + def_bool y + depends on PPC_POWERNV || PPC_PSERIES + config PPC_DCR_NATIVE bool diff --git a/include/linux/cpu.h b/include/linux/cpu.h index 563e697e7779..dd3813959d62 100644 --- a/include/linux/cpu.h +++ b/include/linux/cpu.h @@ -140,7 +140,12 @@ extern void enable_nonboot_cpus(void); static inline int suspend_disable_secondary_cpus(void) { - return freeze_secondary_cpus(0); + int cpu = 0; + + if (IS_ENABLED(CONFIG_PM_SLEEP_SMP_NONZERO_CPU)) + cpu = -1; + + return freeze_secondary_cpus(cpu); } static inline void suspend_enable_secondary_cpus(void) { diff --git a/kernel/cpu.c b/kernel/cpu.c index 6754f3ecfd94..d1bf6e2b4752 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -9,6 +9,7 @@ #include #include #include +#include #include #include #include @@ -1199,8 +1200,15 @@ int freeze_secondary_cpus(int primary) int cpu, error = 0; cpu_maps_update_begin(); - if (!cpu_online(primary)) + if (primary == -1) { primary = cpumask_first(cpu_online_mask); + if (!housekeeping_cpu(primary, HK_FLAG_TIMER)) + primary = housekeeping_any_cpu(HK_FLAG_TIMER); + } else { + if (!cpu_online(primary)) + primary = cpumask_first(cpu_online_mask); + } + /* * We take down all of the non-boot CPUs in one shot to avoid races * with the userspace trying to use the CPU hotplug at the same time diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig index f8fe57d1022e..9bbaaab14b36 100644 --- a/kernel/power/Kconfig +++ b/kernel/power/Kconfig @@ -114,6 +114,15 @@ config PM_SLEEP_SMP depends on PM_SLEEP select HOTPLUG_CPU +config PM_SLEEP_SMP_NONZERO_CPU + def_bool y + depends on PM_SLEEP_SMP + depends on ARCH_SUSPEND_NONZERO_CPU + ---help--- + If an arch can suspend (for suspend, hibernate, kexec, etc) on a + non-zero numbered CPU, it may define ARCH_SUSPEND_NONZERO_CPU. This + will allow nohz_full mask to include CPU0. + config PM_AUTOSLEEP bool "Opportunistic sleep" depends on PM_SLEEP -- 2.20.1