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s390/perf_cpum_sf: Convert to use try_cmpxchg128()

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Convert cmpxchg128() usages to try_cmpxchg128() 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 11:03:17 +01:00
parent b59f103d37
commit e449399ffd
1 changed files with 9 additions and 15 deletions
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24
arch/s390/kernel/perf_cpum_sf.c
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@ -1188,8 +1188,8 @@ static void hw_collect_samples(struct perf_event *event, unsigned long *sdbt,
static void hw_perf_event_update(struct perf_event *event, int flush_all)
{
unsigned long long event_overflow, sampl_overflow, num_sdb;
union hws_trailer_header old, prev, new;
struct hw_perf_event *hwc = &event->hw;
union hws_trailer_header prev, new;
struct hws_trailer_entry *te;
unsigned long *sdbt, sdb;
int done;
@ -1233,13 +1233,11 @@ static void hw_perf_event_update(struct perf_event *event, int flush_all)
/* Reset trailer (using compare-double-and-swap) */
prev.val = READ_ONCE_ALIGNED_128(te->header.val);
do {
old.val = prev.val;
new.val = prev.val;
new.f = 0;
new.a = 1;
new.overflow = 0;
prev.val = cmpxchg128(&te->header.val, old.val, new.val);
} while (prev.val != old.val);
} while (!try_cmpxchg128(&te->header.val, &prev.val, new.val));
/* Advance to next sample-data-block */
sdbt++;
@ -1405,16 +1403,15 @@ static int aux_output_begin(struct perf_output_handle *handle,
static bool aux_set_alert(struct aux_buffer *aux, unsigned long alert_index,
unsigned long long *overflow)
{
union hws_trailer_header old, prev, new;
union hws_trailer_header prev, new;
struct hws_trailer_entry *te;
te = aux_sdb_trailer(aux, alert_index);
prev.val = READ_ONCE_ALIGNED_128(te->header.val);
do {
old.val = prev.val;
new.val = prev.val;
*overflow = old.overflow;
if (old.f) {
*overflow = prev.overflow;
if (prev.f) {
/*
* SDB is already set by hardware.
* Abort and try to set somewhere
@ -1424,8 +1421,7 @@ static bool aux_set_alert(struct aux_buffer *aux, unsigned long alert_index,
}
new.a = 1;
new.overflow = 0;
prev.val = cmpxchg128(&te->header.val, old.val, new.val);
} while (prev.val != old.val);
} while (!try_cmpxchg128(&te->header.val, &prev.val, new.val));
return true;
}
@ -1454,7 +1450,7 @@ static bool aux_set_alert(struct aux_buffer *aux, unsigned long alert_index,
static bool aux_reset_buffer(struct aux_buffer *aux, unsigned long range,
unsigned long long *overflow)
{
union hws_trailer_header old, prev, new;
union hws_trailer_header prev, new;
unsigned long i, range_scan, idx;
unsigned long long orig_overflow;
struct hws_trailer_entry *te;
@ -1486,17 +1482,15 @@ static bool aux_reset_buffer(struct aux_buffer *aux, unsigned long range,
te = aux_sdb_trailer(aux, idx);
prev.val = READ_ONCE_ALIGNED_128(te->header.val);
do {
old.val = prev.val;
new.val = prev.val;
orig_overflow = old.overflow;
orig_overflow = prev.overflow;
new.f = 0;
new.overflow = 0;
if (idx == aux->alert_mark)
new.a = 1;
else
new.a = 0;
prev.val = cmpxchg128(&te->header.val, old.val, new.val);
} while (prev.val != old.val);
} while (!try_cmpxchg128(&te->header.val, &prev.val, new.val));
*overflow += orig_overflow;
}