perf: Remove more code from the fastpath
Peter Zijlstra [Thu, 20 May 2010 17:50:07 +0000 (19:50 +0200)]
Sanity checks cost instructions.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100521090710.852926930@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/perf_event.h
kernel/perf_event.c

index 09cd9c1..fb6c91e 100644 (file)
@@ -803,8 +803,6 @@ struct perf_cpu_context {
 struct perf_output_handle {
        struct perf_event               *event;
        struct perf_mmap_data           *data;
-       unsigned long                   head;
-       unsigned long                   offset;
        unsigned long                   wakeup;
        unsigned long                   size;
        void                            *addr;
index 953ce46..d25c864 100644 (file)
@@ -2967,20 +2967,11 @@ again:
        preempt_enable();
 }
 
-void perf_output_copy(struct perf_output_handle *handle,
+__always_inline void perf_output_copy(struct perf_output_handle *handle,
                      const void *buf, unsigned int len)
 {
-       handle->offset += len;
-
-       /*
-        * Check we didn't copy past our reservation window, taking the
-        * possible unsigned int wrap into account.
-        */
-       if (WARN_ON_ONCE(((long)(handle->head - handle->offset)) < 0))
-               return;
-
        do {
-               unsigned long size = min(handle->size, len);
+               unsigned long size = min_t(unsigned long, handle->size, len);
 
                memcpy(handle->addr, buf, size);
 
@@ -3055,15 +3046,12 @@ int perf_output_begin(struct perf_output_handle *handle,
                        goto fail;
        } while (local_cmpxchg(&data->head, offset, head) != offset);
 
-       handle->offset  = offset;
-       handle->head    = head;
-
        if (head - local_read(&data->wakeup) > data->watermark)
                local_add(data->watermark, &data->wakeup);
 
-       handle->page = handle->offset >> (PAGE_SHIFT + page_order(data));
+       handle->page = offset >> (PAGE_SHIFT + page_order(data));
        handle->page &= data->nr_pages - 1;
-       handle->size = handle->offset & ((PAGE_SIZE << page_order(data)) - 1);
+       handle->size = offset & ((PAGE_SIZE << page_order(data)) - 1);
        handle->addr = data->data_pages[handle->page];
        handle->addr += handle->size;
        handle->size = (PAGE_SIZE << page_order(data)) - handle->size;