summaryrefslogtreecommitdiff
path: root/arch/s390
diff options
context:
space:
mode:
authorFrederic Weisbecker <fweisbec@gmail.com>2014-11-28 21:23:34 +0300
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2014-12-08 11:42:32 +0300
commit1ce2180498fd40ed3f6485fc5daadf4b711f305f (patch)
tree5766a052dba787bb3de5e0af8e9fba0c8f1e52e1 /arch/s390
parent200e7c0ffb1b174a4aeaa05f7f43a91ac0fddde3 (diff)
downloadlinux-1ce2180498fd40ed3f6485fc5daadf4b711f305f.tar.xz
s390/idle: convert open coded idle time seqcount
s390 uses open coded seqcount to synchronize idle time accounting. Lets consolidate it with the standard API. Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/include/asm/idle.h3
-rw-r--r--arch/s390/kernel/idle.c24
2 files changed, 13 insertions, 14 deletions
diff --git a/arch/s390/include/asm/idle.h b/arch/s390/include/asm/idle.h
index 6af037f574b8..113cd963dbbe 100644
--- a/arch/s390/include/asm/idle.h
+++ b/arch/s390/include/asm/idle.h
@@ -9,9 +9,10 @@
#include <linux/types.h>
#include <linux/device.h>
+#include <linux/seqlock.h>
struct s390_idle_data {
- unsigned int sequence;
+ seqcount_t seqcount;
unsigned long long idle_count;
unsigned long long idle_time;
unsigned long long clock_idle_enter;
diff --git a/arch/s390/kernel/idle.c b/arch/s390/kernel/idle.c
index 8814dd9cf644..7a55c29b0b33 100644
--- a/arch/s390/kernel/idle.c
+++ b/arch/s390/kernel/idle.c
@@ -38,15 +38,13 @@ void enabled_wait(void)
trace_hardirqs_off();
/* Account time spent with enabled wait psw loaded as idle time. */
- idle->sequence++;
- smp_wmb();
+ write_seqcount_begin(&idle->seqcount);
idle_time = idle->clock_idle_exit - idle->clock_idle_enter;
idle->clock_idle_enter = idle->clock_idle_exit = 0ULL;
idle->idle_time += idle_time;
idle->idle_count++;
account_idle_time(idle_time);
- smp_wmb();
- idle->sequence++;
+ write_seqcount_end(&idle->seqcount);
}
NOKPROBE_SYMBOL(enabled_wait);
@@ -55,14 +53,14 @@ static ssize_t show_idle_count(struct device *dev,
{
struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
unsigned long long idle_count;
- unsigned int sequence;
+ unsigned int seq;
do {
- sequence = ACCESS_ONCE(idle->sequence);
+ seq = read_seqcount_begin(&idle->seqcount);
idle_count = ACCESS_ONCE(idle->idle_count);
if (ACCESS_ONCE(idle->clock_idle_enter))
idle_count++;
- } while ((sequence & 1) || (ACCESS_ONCE(idle->sequence) != sequence));
+ } while (read_seqcount_retry(&idle->seqcount, seq));
return sprintf(buf, "%llu\n", idle_count);
}
DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
@@ -72,15 +70,15 @@ static ssize_t show_idle_time(struct device *dev,
{
struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
unsigned long long now, idle_time, idle_enter, idle_exit;
- unsigned int sequence;
+ unsigned int seq;
do {
now = get_tod_clock();
- sequence = ACCESS_ONCE(idle->sequence);
+ seq = read_seqcount_begin(&idle->seqcount);
idle_time = ACCESS_ONCE(idle->idle_time);
idle_enter = ACCESS_ONCE(idle->clock_idle_enter);
idle_exit = ACCESS_ONCE(idle->clock_idle_exit);
- } while ((sequence & 1) || (ACCESS_ONCE(idle->sequence) != sequence));
+ } while (read_seqcount_retry(&idle->seqcount, seq));
idle_time += idle_enter ? ((idle_exit ? : now) - idle_enter) : 0;
return sprintf(buf, "%llu\n", idle_time >> 12);
}
@@ -90,14 +88,14 @@ cputime64_t arch_cpu_idle_time(int cpu)
{
struct s390_idle_data *idle = &per_cpu(s390_idle, cpu);
unsigned long long now, idle_enter, idle_exit;
- unsigned int sequence;
+ unsigned int seq;
do {
now = get_tod_clock();
- sequence = ACCESS_ONCE(idle->sequence);
+ seq = read_seqcount_begin(&idle->seqcount);
idle_enter = ACCESS_ONCE(idle->clock_idle_enter);
idle_exit = ACCESS_ONCE(idle->clock_idle_exit);
- } while ((sequence & 1) || (ACCESS_ONCE(idle->sequence) != sequence));
+ } while (read_seqcount_retry(&idle->seqcount, seq));
return idle_enter ? ((idle_exit ?: now) - idle_enter) : 0;
}