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| author | Heiko Carstens <hca@linux.ibm.com> | 2023-02-24 13:02:37 +0300 |
|---|---|---|
| committer | Heiko Carstens <hca@linux.ibm.com> | 2023-02-28 15:19:05 +0300 |
| commit | 5e02c74905cb00184b6c5ae70b1c1bfae5b3bd17 (patch) | |
| tree | 06fbc649485e79c8dc26080ee36b8819a6cc260f /arch | |
| parent | 434b26605f6cc500c1a995587e5c4bc4bc1693c6 (diff) | |
| download | linux-5e02c74905cb00184b6c5ae70b1c1bfae5b3bd17.tar.xz | |
s390/cpum_sf: use READ_ONCE_ALIGNED_128() instead of 128-bit cmpxchg
Use READ_ONCE_ALIGNED_128() to read the previous value in front of a
128-bit cmpxchg loop, instead of (mis-)using a 128-bit cmpxchg operation to
do the same.
This makes the code more readable and is faster.
Link: https://lore.kernel.org/r/20230224100237.3247871-3-hca@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/s390/kernel/perf_cpum_sf.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/arch/s390/kernel/perf_cpum_sf.c b/arch/s390/kernel/perf_cpum_sf.c index 79904a839fb9..e7b867e2f73f 100644 --- a/arch/s390/kernel/perf_cpum_sf.c +++ b/arch/s390/kernel/perf_cpum_sf.c @@ -1355,8 +1355,7 @@ static void hw_perf_event_update(struct perf_event *event, int flush_all) num_sdb++; /* Reset trailer (using compare-double-and-swap) */ - /* READ_ONCE() 16 byte header */ - prev.val = __cdsg(&te->header.val, 0, 0); + prev.val = READ_ONCE_ALIGNED_128(te->header.val); do { old.val = prev.val; new.val = prev.val; @@ -1558,8 +1557,7 @@ static bool aux_set_alert(struct aux_buffer *aux, unsigned long alert_index, struct hws_trailer_entry *te; te = aux_sdb_trailer(aux, alert_index); - /* READ_ONCE() 16 byte header */ - prev.val = __cdsg(&te->header.val, 0, 0); + prev.val = READ_ONCE_ALIGNED_128(te->header.val); do { old.val = prev.val; new.val = prev.val; @@ -1637,8 +1635,7 @@ static bool aux_reset_buffer(struct aux_buffer *aux, unsigned long range, idx_old = idx = aux->empty_mark + 1; for (i = 0; i < range_scan; i++, idx++) { te = aux_sdb_trailer(aux, idx); - /* READ_ONCE() 16 byte header */ - prev.val = __cdsg(&te->header.val, 0, 0); + prev.val = READ_ONCE_ALIGNED_128(te->header.val); do { old.val = prev.val; new.val = prev.val; |