Re: [RFC PATCH v4] Unified trace buffer

From: Steven Rostedt
Date: Fri Sep 26 2008 - 06:45:40 EST



On Fri, 26 Sep 2008, Peter Zijlstra wrote:
> On Thu, 2008-09-25 at 23:20 -0400, Mathieu Desnoyers wrote:
> >
> > You could also fallback on a 2-level page array when buffer size is >
> > 64MB. The cost is mainly a supplementary pointer dereference, but one
> > more should not make sure a big difference overall.
>
> I'm still not sure why we don't just link the pages using the page
> frames, we don't need the random access, do we?

Yeah we can go back to that (as ftrace does).

1) It can be very error prone. I will need to encapsulate the logic more.

2) I'm still not sure if crash can handle it.


I was going to reply to Masami with this answer, but it makes things more
complex. For v1 (non RFC v1) I wanted to start simple. v2 can have this
enhancement.

-- Steve

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