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author | codeworkx <codeworkx@cyanogenmod.com> | 2012-09-18 18:51:21 +0200 |
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committer | codeworkx <codeworkx@cyanogenmod.com> | 2012-09-18 19:02:23 +0200 |
commit | f991bd2a427ec6a5e049e19745aba6a5d7f006c4 (patch) | |
tree | c6f0d428403c32c95335c34b3f0105c2e4c8087d /kernel/cpu.c | |
parent | c28265764ec6ad9995eb0c761a376ffc9f141fcd (diff) | |
parent | bea37381fd9a34c6660e5195d31beea86aa3dda3 (diff) | |
download | kernel_samsung_smdk4412-f991bd2a427ec6a5e049e19745aba6a5d7f006c4.zip kernel_samsung_smdk4412-f991bd2a427ec6a5e049e19745aba6a5d7f006c4.tar.gz kernel_samsung_smdk4412-f991bd2a427ec6a5e049e19745aba6a5d7f006c4.tar.bz2 |
Merge linux-3.0.31 from korg into jellybean
Conflicts:
arch/arm/mm/proc-v7.S
drivers/base/core.c
drivers/gpu/drm/i915/i915_gem_execbuffer.c
drivers/gpu/drm/i915/intel_display.c
drivers/gpu/drm/i915/intel_lvds.c
drivers/gpu/drm/radeon/evergreen.c
drivers/gpu/drm/radeon/r100.c
drivers/gpu/drm/radeon/radeon_connectors.c
drivers/gpu/drm/radeon/rs600.c
drivers/usb/core/hub.c
drivers/usb/host/xhci-pci.c
drivers/usb/host/xhci.c
drivers/usb/serial/qcserial.c
fs/proc/base.c
Change-Id: Ia98b35db3f8c0bfd95817867d3acb85be8e5e772
Diffstat (limited to 'kernel/cpu.c')
-rw-r--r-- | kernel/cpu.c | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 4047707..eae3d9b 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -15,6 +15,7 @@ #include <linux/stop_machine.h> #include <linux/mutex.h> #include <linux/gfp.h> +#include <linux/suspend.h> #ifdef CONFIG_SMP /* Serializes the updates to cpu_online_mask, cpu_present_mask */ @@ -476,6 +477,79 @@ static int alloc_frozen_cpus(void) return 0; } core_initcall(alloc_frozen_cpus); + +/* + * Prevent regular CPU hotplug from racing with the freezer, by disabling CPU + * hotplug when tasks are about to be frozen. Also, don't allow the freezer + * to continue until any currently running CPU hotplug operation gets + * completed. + * To modify the 'cpu_hotplug_disabled' flag, we need to acquire the + * 'cpu_add_remove_lock'. And this same lock is also taken by the regular + * CPU hotplug path and released only after it is complete. Thus, we + * (and hence the freezer) will block here until any currently running CPU + * hotplug operation gets completed. + */ +void cpu_hotplug_disable_before_freeze(void) +{ + cpu_maps_update_begin(); + cpu_hotplug_disabled = 1; + cpu_maps_update_done(); +} + + +/* + * When tasks have been thawed, re-enable regular CPU hotplug (which had been + * disabled while beginning to freeze tasks). + */ +void cpu_hotplug_enable_after_thaw(void) +{ + cpu_maps_update_begin(); + cpu_hotplug_disabled = 0; + cpu_maps_update_done(); +} + +/* + * When callbacks for CPU hotplug notifications are being executed, we must + * ensure that the state of the system with respect to the tasks being frozen + * or not, as reported by the notification, remains unchanged *throughout the + * duration* of the execution of the callbacks. + * Hence we need to prevent the freezer from racing with regular CPU hotplug. + * + * This synchronization is implemented by mutually excluding regular CPU + * hotplug and Suspend/Hibernate call paths by hooking onto the Suspend/ + * Hibernate notifications. + */ +static int +cpu_hotplug_pm_callback(struct notifier_block *nb, + unsigned long action, void *ptr) +{ + switch (action) { + + case PM_SUSPEND_PREPARE: + case PM_HIBERNATION_PREPARE: + cpu_hotplug_disable_before_freeze(); + break; + + case PM_POST_SUSPEND: + case PM_POST_HIBERNATION: + cpu_hotplug_enable_after_thaw(); + break; + + default: + return NOTIFY_DONE; + } + + return NOTIFY_OK; +} + + +int cpu_hotplug_pm_sync_init(void) +{ + pm_notifier(cpu_hotplug_pm_callback, 0); + return 0; +} +core_initcall(cpu_hotplug_pm_sync_init); + #endif /* CONFIG_PM_SLEEP_SMP */ /** |