64 lines
2.0 KiB
Diff
64 lines
2.0 KiB
Diff
From f2d67a7b326442ac173f822b73e8c3cda13f9db1 Mon Sep 17 00:00:00 2001
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Fri, 14 Jun 2013 17:16:35 +0200
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Subject: [PATCH 281/365] kernel/hotplug: restore original cpu mask oncpu/down
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If a task which is allowed to run only on CPU X puts CPU Y down then it
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will be allowed on all CPUs but the on CPU Y after it comes back from
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kernel. This patch ensures that we don't lose the initial setting unless
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the CPU the task is running is going down.
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/cpu.c | 13 ++++++++++++-
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1 file changed, 12 insertions(+), 1 deletion(-)
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diff --git a/kernel/cpu.c b/kernel/cpu.c
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index 1fbc7dd95ccc..072e296c1c12 100644
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--- a/kernel/cpu.c
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+++ b/kernel/cpu.c
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@@ -1308,6 +1308,7 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
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bool hasdied = false;
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int mycpu;
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cpumask_var_t cpumask;
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+ cpumask_var_t cpumask_org;
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if (num_online_cpus() == 1)
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return -EBUSY;
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@@ -1318,6 +1319,12 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
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/* Move the downtaker off the unplug cpu */
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if (!alloc_cpumask_var(&cpumask, GFP_KERNEL))
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return -ENOMEM;
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+ if (!alloc_cpumask_var(&cpumask_org, GFP_KERNEL)) {
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+ free_cpumask_var(cpumask);
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+ return -ENOMEM;
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+ }
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+
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+ cpumask_copy(cpumask_org, tsk_cpus_allowed(current));
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cpumask_andnot(cpumask, cpu_online_mask, cpumask_of(cpu));
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set_cpus_allowed_ptr(current, cpumask);
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free_cpumask_var(cpumask);
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@@ -1326,7 +1333,8 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
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if (mycpu == cpu) {
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printk(KERN_ERR "Yuck! Still on unplug CPU\n!");
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migrate_enable();
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- return -EBUSY;
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+ ret = -EBUSY;
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+ goto restore_cpus;
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}
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cpu_hotplug_begin();
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@@ -1380,6 +1388,9 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen,
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/* This post dead nonsense must die */
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if (!ret && hasdied)
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cpu_notify_nofail(CPU_POST_DEAD, cpu);
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+restore_cpus:
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+ set_cpus_allowed_ptr(current, cpumask_org);
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+ free_cpumask_var(cpumask_org);
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arch_smt_update();
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return ret;
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}
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--
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2.28.0
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