Commit-ID: f80deefa41890f9484802d7b67f11daf28055150
Gitweb: https://git.kernel.org/tip/f80deefa41890f9484802d7b67f11daf28055150
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Thu, 14 Mar 2019 13:25:02 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 3 Apr 2019 09:25:33 +0200
perf/x86: Add sanity checks to x86_schedule_events()
By computing the 'committed' index earlier, we can use it to validate
the cached constraint state.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/events/core.c | 32 +++++++++++++++++++-------------
1 file changed, 19 insertions(+), 13 deletions(-)
diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index fa88acf0daad..24dab9ad4fd6 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -849,17 +849,34 @@ int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
struct event_constraint *c;
unsigned long used_mask[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
struct perf_event *e;
- int i, wmin, wmax, unsched = 0;
+ int n0, i, wmin, wmax, unsched = 0;
struct hw_perf_event *hwc;
bitmap_zero(used_mask, X86_PMC_IDX_MAX);
+ /*
+ * Compute the number of events already present; see x86_pmu_add(),
+ * validate_group() and x86_pmu_commit_txn(). For the former two
+ * cpuc->n_events hasn't been updated yet, while for the latter
+ * cpuc->n_txn contains the number of events added in the current
+ * transaction.
+ */
+ n0 = cpuc->n_events;
+ if (cpuc->txn_flags & PERF_PMU_TXN_ADD)
+ n0 -= cpuc->n_txn;
+
if (x86_pmu.start_scheduling)
x86_pmu.start_scheduling(cpuc);
for (i = 0, wmin = X86_PMC_IDX_MAX, wmax = 0; i < n; i++) {
c = cpuc->event_constraint[i];
+ /*
+ * Previously scheduled events should have a cached constraint,
+ * while new events should not have one.
+ */
+ WARN_ON_ONCE((c && i >= n0) || (!c && i < n0));
+
/*
* Request constraints for new events; or for those events that
* have a dynamic constraint -- for those the constraint can
@@ -937,18 +954,7 @@ int x86_schedule_events(struct cpu_hw_events *cpuc, int n, int *assign)
x86_pmu.commit_scheduling(cpuc, i, assign[i]);
}
} else {
- /*
- * Compute the number of events already present; see
- * x86_pmu_add(), validate_group() and x86_pmu_commit_txn().
- * For the former two cpuc->n_events hasn't been updated yet,
- * while for the latter cpuc->n_txn contains the number of
- * events added in the current transaction.
- */
- i = cpuc->n_events;
- if (cpuc->txn_flags & PERF_PMU_TXN_ADD)
- i -= cpuc->n_txn;
-
- for (; i < n; i++) {
+ for (i = n0; i < n; i++) {
e = cpuc->event_list[i];
/*
|