Re: [PATCH] perf, ibs: Check syscall attribute flags

From: Arnaldo Carvalho de Melo
Date: Mon Sep 10 2012 - 11:37:52 EST

Em Mon, Sep 10, 2012 at 03:07:00PM +0200, Robert Richter escreveu:
> On 07.09.12 11:20:19, David Ahern wrote:
> > I see now... intel returns ENOTSUP if exclude_guest is not set, amd
> > returns EINVAL if it is set.

> > For the AMD case the fallback_missing_features code kicks in for
> > perf-top and perf-record; I just need to fix up the pr_debug for that case.

> It is EOPNOTSUP. I preferred returning EOPNOTSUP too. But then I saw
> that fallback code is implemented to work mostly with EINVAL. It seems
> to be the default answer to a syscall. ;)

> There are several pieces of code in perf that implement fallback code,
> it's hard to find it all and this already caused some bugs in the
> past. I was looking at this to unify it, but it was too much effort.

Indeed these all need to be moved to perf_ev{sel,list}__open, its
something I meant to do long ago, will try again to consolidate that.

- Arnaldo
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