Re: [RFC PATCH] perf: Split up buffer handling from core code

Borislav Petkov
2011-05-19T07:31:41Z

On Thu, May 19, 2011 at 03:06:25AM +0200, Frederic Weisbecker wrote:
> Keeping perf_output_copy() inlined is responsible
> of some ugliness there.
>
> A solution could be to have an internal only
> perf_output_copy_inline() version in internal.h
> and a wrapper in buffer.c that exports it.
>
> Or we can completely uninline it.
>
> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: Stephane Eranian <eranian@google.com>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> ---
> include/linux/perf_event.h | 47 +++++-
> kernel/events/Makefile | 2 +-
> kernel/events/buffer.c | 394 +++++++++++++++++++++++++++++++++++++++
> kernel/events/core.c | 442 +-------------------------------------------
> kernel/events/internal.h | 28 +++
> 5 files changed, 476 insertions(+), 437 deletions(-)
> create mode 100644 kernel/events/buffer.c
> create mode 100644 kernel/events/internal.h
>
> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
> index 3412684..02952d4 100644
> --- a/include/linux/perf_event.h
> +++ b/include/linux/perf_event.h
> @@ -1142,12 +1142,55 @@ extern void perf_bp_event(struct perf_event *event, void *data);
> # define perf_instruction_pointer(regs) instruction_pointer(regs)
> #endif
>
> +#ifdef CONFIG_PERF_USE_VMALLOC
> +/*
> + * Back perf_mmap() with vmalloc memory.
> + *
> + * Required for architectures that have d-cache aliasing issues.
> + */
> +
> +static inline int perf_output_page_order(struct perf_buffer *buffer)
> +{
> + return buffer->page_order;
> +}
> +
> +#else
> +
> +static inline int perf_output_page_order(struct perf_buffer *buffer)
> +{
> + return 0;
> +}
> +#endif
> +
> extern int perf_output_begin(struct perf_output_handle *handle,
> struct perf_event *event, unsigned int size,
> int nmi, int sample);
> extern void perf_output_end(struct perf_output_handle *handle);
> -extern void perf_output_copy(struct perf_output_handle *handle,
> - const void *buf, unsigned int len);
> +
> +static inline void
> +perf_output_copy(struct perf_output_handle *handle,
> + const void *buf, unsigned int len)
> +{
> + do {
> + unsigned long size = min_t(unsigned long, handle->size, len);
> +
> + memcpy(handle->addr, buf, size);
> +
> + len -= size;
> + handle->addr += size;
> + buf += size;
> + handle->size -= size;
> + if (!handle->size) {
> + struct perf_buffer *buffer = handle->buffer;
> +
> + handle->page++;
> + handle->page &= buffer->nr_pages - 1;
> + handle->addr = buffer->data_pages[handle->page];
> + handle->size = PAGE_SIZE << perf_output_page_order(buffer);
> + }
> + } while (len);
> +}

Ok, maybe I'm missing something looking at this from the side but
perf_output_copy is used only internally by perf_event.c, i.e.
events/core.c, why not put it into the internal.h header?

The rest looks ok.

Thanks.

--
Regards/Gruss,
Boris.