perf_events: Update Intel extra regs shared constraints management

This patch improves the code managing the extra shared registers
used for offcore_response events on Intel Nehalem/Westmere. The
idea is to use static allocation instead of dynamic allocation.
This simplifies greatly the get and put constraint routines for
those events.

The patch also renames per_core to shared_regs because the same
data structure gets used whether or not HT is on. When HT is
off, those events still need to coordination because they use
a extra MSR that has to be shared within an event group.

Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110606145703.GA7258@quad
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 11 insertions, 3 deletions

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 771b0b2845e4..069315eefb22 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -536,6 +536,16 @@ struct perf_branch_stack {
 
 struct task_struct;
 
+/*
+ * extra PMU register associated with an event
+ */
+struct hw_perf_event_extra {
+        u64             config; /* register value */
+        unsigned int    reg;    /* register address or index */
+        int             alloc;  /* extra register already allocated */
+        int             idx;    /* index in shared_regs->regs[] */
+};
+
 /**
  * struct hw_perf_event - performance event hardware details:
  */
@@ -549,9 +559,7 @@ struct hw_perf_event {
                         unsigned long   event_base;
                         int             idx;
                         int             last_cpu;
-                        unsigned int    extra_reg;
-                        u64             extra_config;
-                        int             extra_alloc;
+                        struct hw_perf_event_extra extra_reg;
                 };
                 struct { /* software */
                         struct hrtimer  hrtimer;