1 files changed, 43 insertions, 2 deletions

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 5a469d3d0c6..fa6fdec5afb 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -499,11 +499,16 @@ struct sched_state {
         unsigned long used[BITS_TO_LONGS(X86_PMC_IDX_MAX)];
 };
 
+/* Total max is X86_PMC_IDX_MAX, but we are O(n!) limited */
+#define SCHED_STATES_MAX        2
+
 struct perf_sched {
         int                     max_weight;
         int                     max_events;
         struct event_constraint **constraints;
         struct sched_state      state;
+        int                     saved_states;
+        struct sched_state      saved[SCHED_STATES_MAX];
 };
 
 /*
@@ -529,11 +534,34 @@ static void perf_sched_init(struct perf_sched *sched, struct event_constraint **
         sched->state.unassigned = num;
 }
 
+static void perf_sched_save_state(struct perf_sched *sched)
+{
+        if (WARN_ON_ONCE(sched->saved_states >= SCHED_STATES_MAX))
+                return;
+
+        sched->saved[sched->saved_states] = sched->state;
+        sched->saved_states++;
+}
+
+static bool perf_sched_restore_state(struct perf_sched *sched)
+{
+        if (!sched->saved_states)
+                return false;
+
+        sched->saved_states--;
+        sched->state = sched->saved[sched->saved_states];
+
+        /* continue with next counter: */
+        clear_bit(sched->state.counter++, sched->state.used);
+
+        return true;
+}
+
 /*
  * Select a counter for the current event to schedule. Return true on
  * success.
  */
-static bool perf_sched_find_counter(struct perf_sched *sched)
+static bool __perf_sched_find_counter(struct perf_sched *sched)
 {
         struct event_constraint *c;
         int idx;
@@ -557,6 +585,19 @@ static bool perf_sched_find_counter(struct perf_sched *sched)
         if (idx >= X86_PMC_IDX_MAX)
                 return false;
 
+        if (c->overlap)
+                perf_sched_save_state(sched);
+
+        return true;
+}
+
+static bool perf_sched_find_counter(struct perf_sched *sched)
+{
+        while (!__perf_sched_find_counter(sched)) {
+                if (!perf_sched_restore_state(sched))
+                        return false;
+        }
+
         return true;
 }
 
@@ -1250,7 +1291,7 @@ static int __init init_hw_perf_events(void)
 
         unconstrained = (struct event_constraint)
                 __EVENT_CONSTRAINT(0, (1ULL << x86_pmu.num_counters) - 1,
-                                   0, x86_pmu.num_counters);
+                                   0, x86_pmu.num_counters, 0);
 
         if (x86_pmu.event_constraints) {
                 for_each_event_constraint(c, x86_pmu.event_constraints) {