perf_counter: re-arrange the perf_event_type

Breaks ABI yet again :-)

Change the event type so that [0, 2^31-1] are regular event types, but
[2^31, 2^32-1] forms a bitmask for overflow events.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Mackerras <paulus@samba.org>
Orig-LKML-Reference: <20090330171024.047961770@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 25 insertions, 31 deletions

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 4471e7e2c109..d93e9ddf7848 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -1754,50 +1754,44 @@ static void perf_output_end(struct perf_output_handle *handle)
         rcu_read_unlock();
 }
 
-static int perf_output_write(struct perf_counter *counter, int nmi,
-                             void *buf, ssize_t size)
-{
-        struct perf_output_handle handle;
-        int ret;
-
-        ret = perf_output_begin(&handle, counter, size, nmi);
-        if (ret)
-                goto out;
-
-        perf_output_copy(&handle, buf, size);
-        perf_output_end(&handle);
-
-out:
-        return ret;
-}
-
 static void perf_output_simple(struct perf_counter *counter,
                                int nmi, struct pt_regs *regs)
 {
-        unsigned int size;
+        int ret;
+        struct perf_output_handle handle;
+        struct perf_event_header header;
+        u64 ip;
         struct {
-                struct perf_event_header header;
-                u64 ip;
                 u32 pid, tid;
-        } event;
+        } tid_entry;
 
-        event.header.type = PERF_EVENT_IP;
-        event.ip = instruction_pointer(regs);
+        header.type = PERF_EVENT_OVERFLOW;
+        header.size = sizeof(header);
 
-        size = sizeof(event);
+        ip = instruction_pointer(regs);
+        header.type |= __PERF_EVENT_IP;
+        header.size += sizeof(ip);
 
         if (counter->hw_event.include_tid) {
                 /* namespace issues */
-                event.pid = current->group_leader->pid;
-                event.tid = current->pid;
+                tid_entry.pid = current->group_leader->pid;
+                tid_entry.tid = current->pid;
 
-                event.header.type |= __PERF_EVENT_TID;
-        } else
-                size -= sizeof(u64);
+                header.type |= __PERF_EVENT_TID;
+                header.size += sizeof(tid_entry);
+        }
 
-        event.header.size = size;
+        ret = perf_output_begin(&handle, counter, header.size, nmi);
+        if (ret)
+                return;
+
+        perf_output_put(&handle, header);
+        perf_output_put(&handle, ip);
+
+        if (counter->hw_event.include_tid)
+                perf_output_put(&handle, tid_entry);
 
-        perf_output_write(counter, nmi, &event, size);
+        perf_output_end(&handle);
 }
 
 static void perf_output_group(struct perf_counter *counter, int nmi)