61 lines
1.9 KiB
Diff
61 lines
1.9 KiB
Diff
From 4c6df3d78817c20a147c0291f6600d002c0910d3 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] kernel/hotplug: restore original cpu mask oncpu/down
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/3.12/patches-3.12.6-rt9.tar.xz
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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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Cc: stable-rt@vger.kernel.org
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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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--- a/kernel/cpu.c
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+++ b/kernel/cpu.c
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@@ -565,6 +565,7 @@ static int __ref _cpu_down(unsigned int
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.hcpu = hcpu,
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};
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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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@@ -575,6 +576,12 @@ static int __ref _cpu_down(unsigned int
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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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@@ -583,7 +590,8 @@ static int __ref _cpu_down(unsigned int
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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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+ err = -EBUSY;
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+ goto restore_cpus;
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}
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cpu_hotplug_begin();
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@@ -642,6 +650,9 @@ static int __ref _cpu_down(unsigned int
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cpu_hotplug_done();
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if (!err)
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cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu);
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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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return err;
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}
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