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>

diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 037a811..edf5bfb 100644 (file)
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -210,13 +210,15 @@ struct perf_event_header {
 };
 
 enum perf_event_type {
-       PERF_EVENT_IP           = 0,
+
        PERF_EVENT_GROUP        = 1,
 
        PERF_EVENT_MMAP         = 2,
        PERF_EVENT_MUNMAP       = 3,
 
-       __PERF_EVENT_TID        = 0x100,
+       PERF_EVENT_OVERFLOW     = 1UL << 31,
+       __PERF_EVENT_IP         = 1UL << 30,
+       __PERF_EVENT_TID        = 1UL << 29,
 };
 
 #ifdef __KERNEL__

diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index 4471e7e..d93e9dd 100644 (file)
--- 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)