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From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Sebastian Siewior <bigeasy@linutronix.de>,
	x86@kernel.org
Subject: [patch 05/20] x86/mtrr: Remove get_online_cpus() from mtrr_save_state()
Date: Sat, 15 Apr 2017 19:01:12 +0200	[thread overview]
Message-ID: <20170415171651.653561254@linutronix.de> (raw)
In-Reply-To: <20170415170107.643253702@linutronix.de>

[-- Attachment #1: x86mtrr_Remove_get_online_cpus_from_mtrr_save_state.patch --]
[-- Type: text/plain, Size: 936 bytes --]

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

mtrr_save_state() is invoked from native_cpu_up() which is in the context
of a CPU hotplug operation and therefor calling get_online_cpus() is
pointless.

While this works in the current get_online_cpus() implementation it
prevents from converting the hotplug locking to percpu rwsems.

Remove it.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org

---
 arch/x86/kernel/cpu/mtrr/main.c |    2 --
 1 file changed, 2 deletions(-)

--- a/arch/x86/kernel/cpu/mtrr/main.c
+++ b/arch/x86/kernel/cpu/mtrr/main.c
@@ -807,10 +807,8 @@ void mtrr_save_state(void)
 	if (!mtrr_enabled())
 		return;
 
-	get_online_cpus();
 	first_cpu = cpumask_first(cpu_online_mask);
 	smp_call_function_single(first_cpu, mtrr_save_fixed_ranges, NULL, 1);
-	put_online_cpus();
 }
 
 void set_mtrr_aps_delayed_init(void)

  parent reply	other threads:[~2017-04-15 17:31 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-15 17:01 [patch 00/20] cpu/hotplug: Convert get_online_cpus() to a percpu_rwsem Thomas Gleixner
2017-04-15 17:01 ` [patch 01/20] cpu/hotplug: Provide cpuhp_setup/remove_state[_nocalls]_locked() Thomas Gleixner
2017-04-15 17:01 ` [patch 02/20] stop_machine: Provide stop_machine_locked() Thomas Gleixner
2017-04-15 17:01 ` [patch 03/20] padata: Make padata_alloc() static Thomas Gleixner
2017-04-16  6:22   ` Jason A. Donenfeld
2017-04-17  9:14     ` Thomas Gleixner
2017-04-15 17:01 ` [patch 04/20] padata: Avoid nested calls to get_online_cpus() in pcrypt_init_padata() Thomas Gleixner
2017-04-15 17:01 ` Thomas Gleixner [this message]
2017-04-15 17:01 ` [patch 06/20] cpufreq: Use cpuhp_setup_state_nocalls_locked() Thomas Gleixner
2017-04-15 22:54   ` Rafael J. Wysocki
2017-04-17  4:14   ` Viresh Kumar
2017-04-15 17:01 ` [patch 07/20] KVM/PPC/Book3S HV: " Thomas Gleixner
2017-04-15 17:01 ` [patch 08/20] hwtracing/coresight-etm3x: Use the locked version of cpuhp_setup_state_nocalls() Thomas Gleixner
2017-04-15 17:01 ` [patch 09/20] hwtracing/coresight-etm4x: Use cpuhp_setup_state_nocalls_locked() Thomas Gleixner
2017-04-15 17:01 ` [patch 10/20] perf/x86/intel/cqm: Use cpuhp_setup_state_locked() Thomas Gleixner
2017-04-15 17:01 ` [patch 11/20] ARM/hw_breakpoint: " Thomas Gleixner
2017-04-15 17:01 ` [patch 12/20] s390/kernel: Use stop_machine_locked() Thomas Gleixner
2017-04-15 17:01 ` [patch 13/20] powerpc/powernv: " Thomas Gleixner
2017-04-15 17:01 ` [patch 14/20] kernel/hotplug: Use stop_machine_locked() in takedown_cpu() Thomas Gleixner
2017-04-15 17:01 ` [patch 15/20] x86/perf: Drop EXPORT of perf_check_microcode Thomas Gleixner
2017-04-18 11:24   ` Borislav Petkov
2017-04-15 17:01 ` [patch 16/20] perf/x86/intel: Drop get_online_cpus() in intel_snb_check_microcode() Thomas Gleixner
2017-04-18 11:27   ` Borislav Petkov
2017-04-15 17:01 ` [patch 17/20] PCI: Use cpu_hotplug_disable() instead of get_online_cpus() Thomas Gleixner
2017-04-17  6:46   ` Peter Zijlstra
2017-04-17  7:40     ` Thomas Gleixner
2017-04-18 19:44   ` Bjorn Helgaas
2017-04-18 19:51     ` Thomas Gleixner
2017-04-15 17:01 ` [patch 18/20] PCI: Replace the racy recursion prevention Thomas Gleixner
2017-04-15 17:01 ` [patch 19/20] ACPI/processor: Use cpu_hotplug_disable() instead of get_online_cpus() Thomas Gleixner
2017-04-16 22:53   ` Rafael J. Wysocki
2017-04-15 17:01 ` [patch 20/20] cpu/hotplug: Convert hotplug locking to percpu rwsem Thomas Gleixner
2017-04-17  6:50   ` Peter Zijlstra

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