perf/x86: Add flags to event constraints

This patch adds a flags field to each event constraint.
It can be used to store event specific features which can
then later be used by scheduling code or low-level x86 code.

The flags are propagated into event->hw.flags during the
get_event_constraint() call. They are cleared during the
put_event_constraint() call.

This mechanism is going to be used by the PEBS-LL patches.
It avoids defining yet another table to hold event specific
information.

Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Cc: ak@linux.intel.com
Cc: jolsa@redhat.com
Cc: namhyung.kim@lge.com
Link: http://lkml.kernel.org/r/1359040242-8269-4-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

6 files changed, 16 insertions, 7 deletions

diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index 6e8ab0427041..8ba51518f689 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -1489,7 +1489,7 @@ 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);
+                                   0, x86_pmu.num_counters, 0, 0);
 
         x86_pmu.attr_rdpmc = 1; /* enable userspace RDPMC usage by default */
         x86_pmu_format_group.attrs = x86_pmu.format_attrs;
diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index b1518eed5f99..9686d38eb458 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -59,6 +59,7 @@ struct event_constraint {
         u64     cmask;
         int     weight;
         int     overlap;
+        int     flags;
 };
 
 struct amd_nb {
@@ -170,16 +171,17 @@ struct cpu_hw_events {
         void                            *kfree_on_online;
 };
 
-#define __EVENT_CONSTRAINT(c, n, m, w, o) {\
+#define __EVENT_CONSTRAINT(c, n, m, w, o, f) {\
         { .idxmsk64 = (n) },            \
         .code = (c),                    \
         .cmask = (m),                   \
         .weight = (w),                  \
         .overlap = (o),                 \
+        .flags = f,                     \
 }
 
 #define EVENT_CONSTRAINT(c, n, m)       \
-        __EVENT_CONSTRAINT(c, n, m, HWEIGHT(n), 0)
+        __EVENT_CONSTRAINT(c, n, m, HWEIGHT(n), 0, 0)
 
 /*
  * The overlap flag marks event constraints with overlapping counter
@@ -203,7 +205,7 @@ struct cpu_hw_events {
  * and its counter masks must be kept at a minimum.
  */
 #define EVENT_CONSTRAINT_OVERLAP(c, n, m)       \
-        __EVENT_CONSTRAINT(c, n, m, HWEIGHT(n), 1)
+        __EVENT_CONSTRAINT(c, n, m, HWEIGHT(n), 1, 0)
 
 /*
  * Constraint on the Event code.
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index dab7580c47ae..df3beaac3397 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -1392,8 +1392,11 @@ x86_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event)
 
         if (x86_pmu.event_constraints) {
                 for_each_event_constraint(c, x86_pmu.event_constraints) {
-                        if ((event->hw.config & c->cmask) == c->code)
+                        if ((event->hw.config & c->cmask) == c->code) {
+                                /* hw.flags zeroed at initialization */
+                                event->hw.flags |= c->flags;
                                 return c;
+                        }
                 }
         }
 
@@ -1438,6 +1441,7 @@ intel_put_shared_regs_event_constraints(struct cpu_hw_events *cpuc,
 static void intel_put_event_constraints(struct cpu_hw_events *cpuc,
                                         struct perf_event *event)
 {
+        event->hw.flags = 0;
         intel_put_shared_regs_event_constraints(cpuc, event);
 }
 
diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c
index 826054a4f2ee..f30d85bcbda9 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
@@ -430,8 +430,10 @@ struct event_constraint *intel_pebs_constraints(struct perf_event *event)
 
         if (x86_pmu.pebs_constraints) {
                 for_each_event_constraint(c, x86_pmu.pebs_constraints) {
-                        if ((event->hw.config & c->cmask) == c->code)
+                        if ((event->hw.config & c->cmask) == c->code) {
+                                event->hw.flags |= c->flags;
                                 return c;
+                        }
                 }
         }
 
diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
index b43200dbfe7e..75da9e18b128 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c
@@ -2438,7 +2438,7 @@ static int __init uncore_type_init(struct intel_uncore_type *type)
 
         type->unconstrainted = (struct event_constraint)
                 __EVENT_CONSTRAINT(0, (1ULL << type->num_counters) - 1,
-                                0, type->num_counters, 0);
+                                0, type->num_counters, 0, 0);
 
         for (i = 0; i < type->num_boxes; i++) {
                 pmus[i].func_id = -1;
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 1c592114c437..cd3bb2cd9494 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -127,6 +127,7 @@ struct hw_perf_event {
                         int             event_base_rdpmc;
                         int             idx;
                         int             last_cpu;
+                        int             flags;
 
                         struct hw_perf_event_extra extra_reg;
                         struct hw_perf_event_extra branch_reg;