Re: [PATCH 1/2] perf: Add munmap callback

From: "Liang, Kan" <kan.liang@linux.intel.com>
To: Stephane Eranian <eranian@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Borislav Petkov <bp@alien8.de>, Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH 1/2] perf: Add munmap callback
Date: Tue, 6 Nov 2018 11:47:38 -0500	[thread overview]
Message-ID: <46719ae1-7095-f3de-02fe-bc30a36ac523@linux.intel.com> (raw)
In-Reply-To: <CABPqkBQAJXeUmNZLyT_ihShPucO2OpqKBKmKaUMeZt02jHb3OA@mail.gmail.com>

On 11/6/2018 10:00 AM, Stephane Eranian wrote:
>>> /*
>>> * mmap 1 page at the location of the unmap page (should reuse virtual space)
>>> * This creates a continuous region built from two mmaps and
>>> potentially two different sources
>>> * especially with jitted runtimes
>>> */
>> The two mmaps are both anon. As my understanding, we cannot symbolize
>> from the anonymous address, can we?
> Can't we build the same test case using an actual file mapping (both
> mmap from the same file)?
> 

If they are from same file, both mmap have same symbolization name.
We don't need to distinguish them either.

I thought the symbolization issue can only happen when two mmaps are 
from different sources. Right?

Thanks,
Kan