diff options
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_amd.c | 68 |
1 files changed, 26 insertions, 42 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_amd.c b/arch/x86/kernel/cpu/perf_event_amd.c index c93bc4e813a0..e7963c7af683 100644 --- a/arch/x86/kernel/cpu/perf_event_amd.c +++ b/arch/x86/kernel/cpu/perf_event_amd.c @@ -256,9 +256,8 @@ amd_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event) { struct hw_perf_event *hwc = &event->hw; struct amd_nb *nb = cpuc->amd_nb; - struct perf_event *old = NULL; - int max = x86_pmu.num_counters; - int i, j, k = -1; + struct perf_event *old; + int idx, new = -1; /* * if not NB event or no NB, then no constraints @@ -276,48 +275,33 @@ amd_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event) * because of successive calls to x86_schedule_events() from * hw_perf_group_sched_in() without hw_perf_enable() */ - for (i = 0; i < max; i++) { - /* - * keep track of first free slot - */ - if (k == -1 && !nb->owners[i]) - k = i; + for (idx = 0; idx < x86_pmu.num_counters; idx++) { + if (new == -1 || hwc->idx == idx) + /* assign free slot, prefer hwc->idx */ + old = cmpxchg(nb->owners + idx, NULL, event); + else if (nb->owners[idx] == event) + /* event already present */ + old = event; + else + continue; + + if (old && old != event) + continue; + + /* reassign to this slot */ + if (new != -1) + cmpxchg(nb->owners + new, event, NULL); + new = idx; /* already present, reuse */ - if (nb->owners[i] == event) - goto done; - } - /* - * not present, so grab a new slot - * starting either at: - */ - if (hwc->idx != -1) { - /* previous assignment */ - i = hwc->idx; - } else if (k != -1) { - /* start from free slot found */ - i = k; - } else { - /* - * event not found, no slot found in - * first pass, try again from the - * beginning - */ - i = 0; - } - j = i; - do { - old = cmpxchg(nb->owners+i, NULL, event); - if (!old) + if (old == event) break; - if (++i == max) - i = 0; - } while (i != j); -done: - if (!old) - return &nb->event_constraints[i]; - - return &emptyconstraint; + } + + if (new == -1) + return &emptyconstraint; + + return &nb->event_constraints[new]; } static struct amd_nb *amd_alloc_nb(int cpu) |