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Commit f80deefa authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

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: default avatarPeter 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: default avatarIngo Molnar <mingo@kernel.org>
parent 109717de

arch/x86/events/core.c

+19 −13
Original line number Diff line number Diff line
@@ -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];



			/*