From a394a589c55211cdd8224dd8baf3fed109c1da28 Mon Sep 17 00:00:00 2001 From: Josh Boyer Date: Jul 25 2012 12:05:41 +0000 Subject: Add patch to fix cpu pinning after suspend/resume (rhbz 714271) --- diff --git a/CPU-hotplug-cpusets-suspend-Dont-modify-cpusets-during.patch b/CPU-hotplug-cpusets-suspend-Dont-modify-cpusets-during.patch new file mode 100644 index 0000000..f57ecee --- /dev/null +++ b/CPU-hotplug-cpusets-suspend-Dont-modify-cpusets-during.patch @@ -0,0 +1,139 @@ +From 0c1508129adc051fabaf8debefea79baa2f1a81b Mon Sep 17 00:00:00 2001 +From: "Srivatsa S. Bhat" +Date: Thu, 24 May 2012 19:46:26 +0530 +Subject: [PATCH] CPU hotplug, cpusets, suspend: Don't modify cpusets during + suspend/resume + +In the event of CPU hotplug, the kernel modifies the cpusets' cpus_allowed +masks as and when necessary to ensure that the tasks belonging to the cpusets +have some place (online CPUs) to run on. And regular CPU hotplug is +destructive in the sense that the kernel doesn't remember the original cpuset +configurations set by the user, across hotplug operations. + +However, suspend/resume (which uses CPU hotplug) is a special case in which +the kernel has the responsibility to restore the system (during resume), to +exactly the same state it was in before suspend. + +In order to achieve that, do the following: + +1. Don't modify cpusets during suspend/resume. At all. + In particular, don't move the tasks from one cpuset to another, and + don't modify any cpuset's cpus_allowed mask. So, simply ignore cpusets + during the CPU hotplug operations that are carried out in the + suspend/resume path. + +2. However, cpusets and sched domains are related. We just want to avoid + altering cpusets alone. So, to keep the sched domains updated, build + a single sched domain (containing all active cpus) during each of the + CPU hotplug operations carried out in s/r path, effectively ignoring + the cpusets' cpus_allowed masks. + + (Since userspace is frozen while doing all this, it will go unnoticed.) + +3. During the last CPU online operation during resume, build the sched + domains by looking up the (unaltered) cpusets' cpus_allowed masks. + That will bring back the system to the same original state as it was in + before suspend. + +Ultimately, this will not only solve the cpuset problem related to suspend +resume (ie., restores the cpusets to exactly what it was before suspend, by +not touching it at all) but also speeds up suspend/resume because we avoid +running cpuset update code for every CPU being offlined/onlined. + +Signed-off-by: Srivatsa S. Bhat +Signed-off-by: Peter Zijlstra +Cc: Linus Torvalds +Cc: Andrew Morton +Cc: Thomas Gleixner +Link: http://lkml.kernel.org/r/20120524141611.3692.20155.stgit@srivatsabhat.in.ibm.com +Signed-off-by: Ingo Molnar +--- + kernel/cpuset.c | 3 +++ + kernel/sched/core.c | 40 ++++++++++++++++++++++++++++++++++++---- + 2 files changed, 39 insertions(+), 4 deletions(-) + +--- linux-3.4.6-3.1.fc17.noarch.orig/kernel/cpuset.c ++++ linux-3.4.6-3.1.fc17.noarch/kernel/cpuset.c +@@ -2065,6 +2065,9 @@ static void scan_for_empty_cpusets(struc + * (of no affect) on systems that are actively using CPU hotplug + * but making no active use of cpusets. + * ++ * The only exception to this is suspend/resume, where we don't ++ * modify cpusets at all. ++ * + * This routine ensures that top_cpuset.cpus_allowed tracks + * cpu_active_mask on each CPU hotplug (cpuhp) event. + * +--- linux-3.4.6-3.1.fc17.noarch.orig/kernel/sched/core.c ++++ linux-3.4.6-3.1.fc17.noarch/kernel/sched/core.c +@@ -6931,34 +6931,66 @@ int __init sched_create_sysfs_power_savi + } + #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ + ++static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ ++ + /* + * Update cpusets according to cpu_active mask. If cpusets are + * disabled, cpuset_update_active_cpus() becomes a simple wrapper + * around partition_sched_domains(). ++ * ++ * If we come here as part of a suspend/resume, don't touch cpusets because we ++ * want to restore it back to its original state upon resume anyway. + */ + static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, + void *hcpu) + { +- switch (action & ~CPU_TASKS_FROZEN) { ++ switch (action) { ++ case CPU_ONLINE_FROZEN: ++ case CPU_DOWN_FAILED_FROZEN: ++ ++ /* ++ * num_cpus_frozen tracks how many CPUs are involved in suspend ++ * resume sequence. As long as this is not the last online ++ * operation in the resume sequence, just build a single sched ++ * domain, ignoring cpusets. ++ */ ++ num_cpus_frozen--; ++ if (likely(num_cpus_frozen)) { ++ partition_sched_domains(1, NULL, NULL); ++ break; ++ } ++ ++ /* ++ * This is the last CPU online operation. So fall through and ++ * restore the original sched domains by considering the ++ * cpuset configurations. ++ */ ++ + case CPU_ONLINE: + case CPU_DOWN_FAILED: + cpuset_update_active_cpus(); +- return NOTIFY_OK; ++ break; + default: + return NOTIFY_DONE; + } ++ return NOTIFY_OK; + } + + static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, + void *hcpu) + { +- switch (action & ~CPU_TASKS_FROZEN) { ++ switch (action) { + case CPU_DOWN_PREPARE: + cpuset_update_active_cpus(); +- return NOTIFY_OK; ++ break; ++ case CPU_DOWN_PREPARE_FROZEN: ++ num_cpus_frozen++; ++ partition_sched_domains(1, NULL, NULL); ++ break; + default: + return NOTIFY_DONE; + } ++ return NOTIFY_OK; + } + + void __init sched_init_smp(void) diff --git a/kernel.spec b/kernel.spec index b543120..03ff3d3 100644 --- a/kernel.spec +++ b/kernel.spec @@ -54,7 +54,7 @@ Summary: The Linux kernel # For non-released -rc kernels, this will be appended after the rcX and # gitX tags, so a 3 here would become part of release "0.rcX.gitX.3" # -%global baserelease 3 +%global baserelease 4 %global fedora_build %{baserelease} # base_sublevel is the kernel version we're starting with and patching @@ -771,6 +771,9 @@ Patch22056: crypto-aesni-intel-fix-wrong-kfree-pointer.patch #rhbz 772730 Patch22058: ACPI-AC-check-the-return-value-of-power_supply_register.patch +#rhbz 714271 +Patch22060: CPU-hotplug-cpusets-suspend-Dont-modify-cpusets-during.patch + # END OF PATCH DEFINITIONS %endif @@ -1482,6 +1485,9 @@ ApplyPatch crypto-aesni-intel-fix-wrong-kfree-pointer.patch #rhbz 772730 ApplyPatch ACPI-AC-check-the-return-value-of-power_supply_register.patch +#rhbz 714271 +ApplyPatch CPU-hotplug-cpusets-suspend-Dont-modify-cpusets-during.patch + # END OF PATCH APPLICATIONS %endif @@ -2343,6 +2349,9 @@ fi # '-' | | # '-' %changelog +* Wed Jul 25 2012 Josh Boyer +- Add patch to fix cpu pinning after suspend/resume (rhbz 714271) + * Fri Jul 20 2012 Josh Boyer - Update vga_default_device.patch to fix build failures (rhbz 830446)