Date: Tue, 30 Jun 2015 11:50:49 -0300
From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Hou Pengyang <houpengyang@huawei.com>
Cc: mingo@redhat.com, namhyung@kernel.org, a.p.zijlstra@chello.nl,
        wangnan0@huawei.com, linux-kernel@vger.kernel.org, zhu.wen-jie@hp.com
Subject: Re: [RFC] perf tools: Add hugetlbfs memory recognition
Message-ID: <20150630145049.GE5888@kernel.org>
References: <1435394953-146405-1-git-send-email-houpengyang@huawei.com>
 <558E6804.5060602@huawei.com>
 <20150629132329.GC11747@kernel.org>
 <20150629134234.GD11747@kernel.org>
 <55926251.9000404@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <55926251.9000404@huawei.com>
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1716
Lines: 41

Em Tue, Jun 30, 2015 at 05:33:05PM +0800, Hou Pengyang escreveu:
> On 2015/6/29 21:42, Arnaldo Carvalho de Melo wrote:
> >Em Mon, Jun 29, 2015 at 10:23:29AM -0300, Arnaldo Carvalho de Melo escreveu:
> >>Em Sat, Jun 27, 2015 at 05:08:20PM +0800, Hou Pengyang escreveu:
> >>>So I wonder if there is a need to read /proc/pid/smaps instead of
> >>>/proc/pid/maps to generate MMAP2 event. Or we should solve the problem by
> >>>another way?
> >>
> >>Doing some research now...
> >
> >Bummer, seems that only smaps -> ... -> show_smap_vma_flags() will
> >expose that to userspace...
> >
> >Perhaps we can look at some global stat for HugeTLB fs to figure out if
> >we really, really need to parse smaps instead of just maps? I.e. in my
> >system, a desktop one, F21, I have:
> >
> 
> It seems no other info tell us if one process is using hugetlbfs.
> So how about an option to tell perf explicitly which file is from
> hugetlbfs, like:
> 
> ./perf report --hugetlb-file=/mnt/huge/hugepagefile
> 
> So that, we can check if a mmap area is from hugetlbfs by its name
> instead of MAP_HUGETLB.

Well, we _can_ detect this automatically, its just a matter of parsing
/proc/PID/smaps, right?

What I was discussing was a way only parse smaps when we know we need
to, i.e. when we, for instance, parsing /proc/PID/maps, find a map that
we think may be a hugetlb one, maybe some other way to tell us that
hugetlb maps are in place, looking at the hugetlbfs stats somehow?

- Arnaldo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/