Messages in this thread | | | From | Alexander Shishkin <> | Subject | Re: [RFC v2 6/7] perf: add api for pmus to write to AUX space | Date | Wed, 25 Jun 2014 14:24:51 +0300 |
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Peter Zijlstra <peterz@infradead.org> writes:
> On Wed, Jun 11, 2014 at 06:41:49PM +0300, Alexander Shishkin wrote: >> +void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size, >> + bool truncated) >> +{ >> + struct ring_buffer *rb = handle->rb; >> + unsigned long aux_head; >> + >> + aux_head = local_read(&rb->aux_head); >> + local_add(size, &rb->aux_head); >> + >> + rb->user_page->aux_head = local_read(&rb->aux_head); >> + smp_wmb(); >> + >> + perf_output_wakeup(handle); >> + handle->event = NULL; >> + >> + ring_buffer_put(rb); >> +} > > This thing is distinctly less complex than perf_output_put_handle().. ?
This one doesn't support nested writers, but there shouldn't be any either. But I notice now that the barrier is misplaced. Wakeup watermark is not yet taken care of, but will be. Anything else I'm missing?
Regards, -- Alex
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