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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2014-11-28 21:23:34 +0300 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2014-12-08 11:42:32 +0300 |
| commit | 1ce2180498fd40ed3f6485fc5daadf4b711f305f (patch) | |
| tree | 5766a052dba787bb3de5e0af8e9fba0c8f1e52e1 /arch/s390 | |
| parent | 200e7c0ffb1b174a4aeaa05f7f43a91ac0fddde3 (diff) | |
| download | linux-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.h | 3 | ||||
| -rw-r--r-- | arch/s390/kernel/idle.c | 24 |
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; } |