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>
diff --git a/arch/s390/kernel/idle.c b/arch/s390/kernel/idle.c
index 8814dd9..7a55c29 100644
--- a/arch/s390/kernel/idle.c
+++ b/arch/s390/kernel/idle.c
@@ -38,15 +38,13 @@
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 @@
{
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 @@
{
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 @@
{
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;
}
