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s390/perf_cpum_cf: Convert to use local64_try_cmpxchg()

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Convert local64_cmpxchg() usages to local64_try_cmpxchg() in
order to generate slightly better code.

Reviewed-by: Juergen Christ <jchrist@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
This commit is contained in:
Heiko Carstens 2024-11-06 11:03:18 +01:00
parent e449399ffd
commit 42898f74b2
1 changed files with 4 additions and 4 deletions
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8
arch/s390/kernel/perf_cpum_cf.c
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@ -879,8 +879,8 @@ static int hw_perf_event_reset(struct perf_event *event)
u64 prev, new;
int err;
prev = local64_read(&event->hw.prev_count);
do {
prev = local64_read(&event->hw.prev_count);
err = ecctr(event->hw.config, &new);
if (err) {
if (err != 3)
@ -892,7 +892,7 @@ static int hw_perf_event_reset(struct perf_event *event)
*/
new = 0;
}
} while (local64_cmpxchg(&event->hw.prev_count, prev, new) != prev);
} while (!local64_try_cmpxchg(&event->hw.prev_count, &prev, new));
return err;
}
@ -902,12 +902,12 @@ static void hw_perf_event_update(struct perf_event *event)
u64 prev, new, delta;
int err;
prev = local64_read(&event->hw.prev_count);
do {
prev = local64_read(&event->hw.prev_count);
err = ecctr(event->hw.config, &new);
if (err)
return;
} while (local64_cmpxchg(&event->hw.prev_count, prev, new) != prev);
} while (!local64_try_cmpxchg(&event->hw.prev_count, &prev, new));
delta = (prev <= new) ? new - prev
: (-1ULL - prev) + new + 1; /* overflow */