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From: Frederic Weisbecker <fweisbec@gmail.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Preeti U Murthy <preeti@linux.vnet.ibm.com>,
	Christoph Lameter <cl@linux.com>, Ingo Molnar <mingo@kernel.org>,
	Viresh Kumar <viresh.kumar@linaro.org>,
	Rik van Riel <riel@redhat.com>
Subject: [PATCH 2/8] apm32: Fix cputime == jiffies assumption
Date: Thu, 11 Jun 2015 19:36:02 +0200	[thread overview]
Message-ID: <1434044168-23173-3-git-send-email-fweisbec@gmail.com> (raw)
In-Reply-To: <1434044168-23173-1-git-send-email-fweisbec@gmail.com>

That code wrongly assumes that cputime_t wraps jiffies_t. Lets use
the correct accessors/mutators.

No real harm now as that code can't be used with full dynticks.

Cc: Christoph Lameter <cl@linux.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc; John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
 arch/x86/kernel/apm_32.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/apm_32.c b/arch/x86/kernel/apm_32.c
index 927ec92..052c9c3 100644
--- a/arch/x86/kernel/apm_32.c
+++ b/arch/x86/kernel/apm_32.c
@@ -919,7 +919,7 @@ recalc:
 	} else if (jiffies_since_last_check > idle_period) {
 		unsigned int idle_percentage;
 
-		idle_percentage = stime - last_stime;
+		idle_percentage = cputime_to_jiffies(stime - last_stime);
 		idle_percentage *= 100;
 		idle_percentage /= jiffies_since_last_check;
 		use_apm_idle = (idle_percentage > idle_threshold);
-- 
2.1.4


  parent reply	other threads:[~2015-06-11 17:36 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-11 17:36 [PATCH 0/8] tick/nohz: Tick dependency quick check + cleanups Frederic Weisbecker
2015-06-11 17:36 ` [PATCH 1/8] jiffies: Remove HZ > USEC_PER_SEC special case Frederic Weisbecker
2015-06-11 20:46   ` Rik van Riel
2015-06-11 17:36 ` Frederic Weisbecker [this message]
2015-06-11 20:47   ` [PATCH 2/8] apm32: Fix cputime == jiffies assumption Rik van Riel
2015-06-11 17:36 ` [PATCH 3/8] alpha: Fix jiffies based cputime assumption Frederic Weisbecker
2015-06-11 20:47   ` Rik van Riel
2015-06-11 17:36 ` [PATCH 4/8] nohz: Remove idle task special case Frederic Weisbecker
2015-06-11 20:47   ` Rik van Riel
2015-06-14  1:44   ` Preeti U Murthy
2015-07-07 14:45     ` Frederic Weisbecker
2015-06-11 17:36 ` [PATCH 5/8] nohz: Restart the tick from irq exit Frederic Weisbecker
2015-06-11 20:48   ` Rik van Riel
2015-06-12  7:32   ` Peter Zijlstra
2015-06-12 12:38     ` Frederic Weisbecker
2015-06-12 12:59       ` Peter Zijlstra
2015-06-12 13:06         ` Frederic Weisbecker
2015-06-14  9:30       ` Preeti U Murthy
2015-07-07 14:23         ` Frederic Weisbecker
2015-06-14  9:18   ` Preeti U Murthy
2015-06-14  9:19   ` Preeti U Murthy
2015-07-07 14:20     ` Frederic Weisbecker
2015-06-11 17:36 ` [PATCH 6/8] nohz: Move tick_nohz_restart_sched_tick() above its users Frederic Weisbecker
2015-06-11 20:48   ` Rik van Riel
2015-06-11 17:36 ` [PATCH 7/8] nohz: Evaluate tick dependency once on context switch Frederic Weisbecker
2015-06-11 20:46   ` Rik van Riel
2015-06-17  5:59     ` Preeti U Murthy
2015-07-07 14:30     ` Frederic Weisbecker
2015-06-12  7:36   ` Peter Zijlstra
2015-07-06 16:14     ` Frederic Weisbecker
2015-06-11 17:36 ` [PATCH 8/8] nohz: Remove useless argument on tick_nohz_task_switch() Frederic Weisbecker

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