Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1320364

[PATCH v7 2/6] cpufreq: powernv: Hot-plug safe the kworker thread

From Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Newsgroups linux.kernel
Subject [PATCH v7 2/6] cpufreq: powernv: Hot-plug safe the kworker thread
Date 2016-01-28 08:30 +0100
Message-ID <qVPbH-8rA-3@gated-at.bofh.it> (permalink)
References <qVPbH-8rA-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

Show all headers | View raw


In the kworker_thread powernv_cpufreq_work_fn(), we can end up
sending an IPI to a cpu going offline. This is a rare corner case
which is fixed using {get/put}_online_cpus(). Along with this fix,
this patch adds changes to do oneshot cpumask_{clear/and} operation.

Suggested-by: Shreyas B Prabhu <shreyas@linux.vnet.ibm.com>
Suggested-by: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
---
No changes from v6.

Changes form v5:
- Fix the kbuild-error:
drivers/cpufreq/powernv-cpufreq.c:428:2: error: implicit declaration of
function 'get_online_cpus' [-Werror=implicit-function-declaration

 drivers/cpufreq/powernv-cpufreq.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/cpufreq/powernv-cpufreq.c b/drivers/cpufreq/powernv-cpufreq.c
index 53f980b..a271b0f 100644
--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -28,6 +28,7 @@
 #include <linux/of.h>
 #include <linux/reboot.h>
 #include <linux/slab.h>
+#include <linux/cpu.h>
 
 #include <asm/cputhreads.h>
 #include <asm/firmware.h>
@@ -423,18 +424,19 @@ void powernv_cpufreq_work_fn(struct work_struct *work)
 {
 	struct chip *chip = container_of(work, struct chip, throttle);
 	unsigned int cpu;
-	cpumask_var_t mask;
+	cpumask_t mask;
 
-	smp_call_function_any(&chip->mask,
+	get_online_cpus();
+	cpumask_and(&mask, &chip->mask, cpu_online_mask);
+	smp_call_function_any(&mask,
 			      powernv_cpufreq_throttle_check, NULL, 0);
 
 	if (!chip->restore)
-		return;
+		goto out;
 
 	chip->restore = false;
-	cpumask_copy(mask, &chip->mask);
-	for_each_cpu_and(cpu, mask, cpu_online_mask) {
-		int index, tcpu;
+	for_each_cpu(cpu, &mask) {
+		int index;
 		struct cpufreq_policy policy;
 
 		cpufreq_get_policy(&policy, cpu);
@@ -442,9 +444,10 @@ void powernv_cpufreq_work_fn(struct work_struct *work)
 					       policy.cur,
 					       CPUFREQ_RELATION_C, &index);
 		powernv_cpufreq_target_index(&policy, index);
-		for_each_cpu(tcpu, policy.cpus)
-			cpumask_clear_cpu(tcpu, mask);
+		cpumask_andnot(&mask, &mask, policy.cpus);
 	}
+out:
+	put_online_cpus();
 }
 
 static char throttle_reason[][30] = {
-- 
1.9.3

Back to linux.kernel | Previous | NextPrevious in thread | Next in thread | Find similar | Unroll thread


Thread

[PATCH v7 0/6] cpufreq: powernv: Redesign the presentation of throttle notification and solve bug-fixes in the driver Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com> - 2016-01-28 08:30 +0100
  [PATCH v7 2/6] cpufreq: powernv: Hot-plug safe the kworker thread Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com> - 2016-01-28 08:30 +0100
  [PATCH v7 3/6] cpufreq: powernv: Remove cpu_to_chip_id() from hot-path Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com> - 2016-01-28 08:30 +0100
    Re: [PATCH v7 3/6] cpufreq: powernv: Remove cpu_to_chip_id() from  hot-path Gautham R Shenoy <ego@linux.vnet.ibm.com> - 2016-01-28 09:20 +0100
    Re: [PATCH v7 3/6] cpufreq: powernv: Remove cpu_to_chip_id() from  hot-path Viresh Kumar <viresh.kumar@linaro.org> - 2016-01-28 09:30 +0100
  [PATCH v7 6/6] cpufreq: powernv: Add sysfs attributes to show throttle stats Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com> - 2016-01-28 08:30 +0100
    Re: [PATCH v7 6/6] cpufreq: powernv: Add sysfs attributes to show  throttle stats Gautham R Shenoy <ego@linux.vnet.ibm.com> - 2016-01-28 09:40 +0100
    Re: [PATCH v7 6/6] cpufreq: powernv: Add sysfs attributes to show  throttle stats Viresh Kumar <viresh.kumar@linaro.org> - 2016-01-28 09:50 +0100
      Re: [PATCH v7 6/6] cpufreq: powernv: Add sysfs attributes to show  throttle stats Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com> - 2016-01-28 10:40 +0100
        Re: [PATCH v7 6/6] cpufreq: powernv: Add sysfs attributes to show  throttle stats Viresh Kumar <viresh.kumar@linaro.org> - 2016-01-28 10:50 +0100
          Re: [PATCH v7 6/6] cpufreq: powernv: Add sysfs attributes to show  throttle stats Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com> - 2016-01-28 11:00 +0100
    Re: [PATCH v7 6/6] cpufreq: powernv: Add sysfs attributes to show  throttle stats Viresh Kumar <viresh.kumar@linaro.org> - 2016-01-28 12:50 +0100
  [PATCH v7 5/6] cpufreq: powernv: Replace pr_info with trace print for throttle event Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com> - 2016-01-28 08:30 +0100
    Re: [PATCH v7 5/6] cpufreq: powernv: Replace pr_info with trace  print for throttle event Gautham R Shenoy <ego@linux.vnet.ibm.com> - 2016-01-28 09:20 +0100
    Re: [PATCH v7 5/6] cpufreq: powernv: Replace pr_info with trace  print for throttle event Viresh Kumar <viresh.kumar@linaro.org> - 2016-01-28 09:30 +0100
  [PATCH v7 1/6] cpufreq: powernv: Free 'chips' on module exit Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com> - 2016-01-28 08:30 +0100
    Re: [PATCH v7 1/6] cpufreq: powernv: Free 'chips' on module exit Gautham R Shenoy <ego@linux.vnet.ibm.com> - 2016-01-28 09:10 +0100
    Re: [PATCH v7 1/6] cpufreq: powernv: Free 'chips' on module exit Viresh Kumar <viresh.kumar@linaro.org> - 2016-01-28 09:30 +0100
  [PATCH v7 4/6] cpufreq: powernv/tracing: Add powernv_throttle tracepoint Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com> - 2016-01-28 08:30 +0100
  Re: [PATCH v7 0/6] cpufreq: powernv: Redesign the presentation of  throttle notification and solve bug-fixes in the driver Viresh Kumar <viresh.kumar@linaro.org> - 2016-01-28 09:30 +0100
  Re: [PATCH v7 0/6] cpufreq: powernv: Redesign the presentation of  throttle notification and solve bug-fixes in the driver Balbir Singh <bsingharora@gmail.com> - 2016-01-28 12:20 +0100

csiph-web