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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@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2019-03-14 13:25:02 +01:00 committed by Ingo Molnar
parent 109717de57
commit f80deefa41
1 changed files with 19 additions and 13 deletions
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32
arch/x86/events/core.c
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@ -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];
/*