Messages in this thread | | | Date | Mon, 18 Mar 2013 14:18:12 +0100 | Subject | Re: [PATCH] perf: fix ring_buffer perf_output_space() boundary calculation | From | Stephane Eranian <> |
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On Mon, Mar 18, 2013 at 2:11 PM, Peter Zijlstra <peterz@infradead.org> wrote: > On Mon, 2013-03-18 at 14:03 +0100, Stephane Eranian wrote: >> On Mon, Mar 18, 2013 at 1:59 PM, Peter Zijlstra <peterz@infradead.org> wrote: >> > On Mon, 2013-03-18 at 13:48 +0100, Stephane Eranian wrote: >> >> if (!rb->writable) >> >> - return true; >> >> + return false; >> > >> > >> > writable means user writable (VM_WRITE); the difference is that a >> > !VM_WRITE buffer will simply over-write its own tail whereas a VM_WRITE >> > buffer will drop events. >> > >> > So returning true for !VM_WRITE makes sense, there's always space. >> > >> Ok, that was not so clear to me. I think this if() statment deserves a comment. >> I will add that in V2. > > Thanks; I suppose renaming the entire ->writable thing might be better > though. Something like ->overwrite or so. > Yes. And if you do this you invert the logic of the field. overwrite=1 -> !VM_WRITE overwrite=0 -> VM_WRITE
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