Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759622Ab3HNKaL (ORCPT ); Wed, 14 Aug 2013 06:30:11 -0400 Received: from mail-oa0-f53.google.com ([209.85.219.53]:64793 "EHLO mail-oa0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759500Ab3HNKaJ (ORCPT ); Wed, 14 Aug 2013 06:30:09 -0400 MIME-Version: 1.0 In-Reply-To: <20130813233449.GK23412@tassilo.jf.intel.com> References: <1376394957-31691-1-git-send-email-eranian@google.com> <1376394957-31691-3-git-send-email-eranian@google.com> <20130813233449.GK23412@tassilo.jf.intel.com> Date: Wed, 14 Aug 2013 12:30:08 +0200 Message-ID: Subject: Re: [PATCH v1 2/2] perf tools: add attr->mmap2 support From: Stephane Eranian To: Andi Kleen Cc: LKML , Peter Zijlstra , "mingo@elte.hu" , Arnaldo Carvalho de Melo , Jiri Olsa , Namhyung Kim , David Ahern Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1353 Lines: 31 On Wed, Aug 14, 2013 at 1:34 AM, Andi Kleen wrote: > On Tue, Aug 13, 2013 at 01:55:57PM +0200, Stephane Eranian wrote: >> This patch adds support for the new PERF_RECORD_MMAP2 >> record type exposed by the kernel. This is an extended >> PERF_RECORD_MMAP record. It adds for each file-backed >> mapping the device major, minor number and the inode >> number. This triplet uniquely identifies the source >> of a file-backed mapping. It can be used to detect >> identical virtual mappings between processes for instance. > > Can you also add the generation number please? > That would make it even more unique. > I assume you're talkng about inode->i_generation, right? I could add that one easily. I am surprised to see: mm/shmem.c: static struct inode *shmem_get_inode(struct super_block *sb, const struct inode *dir, umode_t mode, dev_t dev, unsigned long flags) { inode->i_generation = get_seconds(); } I am assuming that the uniqueness for SHM is coming from the SHMID and therefore a poor quality i_generation is sufficient here. -- 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/