From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754590AbbAGRZG (ORCPT ); Wed, 7 Jan 2015 12:25:06 -0500 Received: from mta-out1.inet.fi ([62.71.2.227]:44304 "EHLO kirsi1.inet.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754237AbbAGRZB (ORCPT ); Wed, 7 Jan 2015 12:25:01 -0500 Date: Wed, 7 Jan 2015 19:24:52 +0200 From: "Kirill A. Shutemov" To: Petr Cermak Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Bjorn Helgaas , Primiano Tucci , Hugh Dickins Subject: Re: [PATCH v2 2/2] task_mmu: Add user-space support for resetting mm->hiwater_rss (peak RSS) Message-ID: <20150107172452.GA7922@node.dhcp.inet.fi> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 07, 2015 at 05:06:54PM +0000, Petr Cermak wrote: > Peak resident size of a process can be reset by writing "5" to > /proc/pid/clear_refs. The driving use-case for this would be getting the > peak RSS value, which can be retrieved from the VmHWM field in > /proc/pid/status, per benchmark iteration or test scenario. And how it's not an ABI break? We have never-lowering VmHWM for 9+ years. How can you know that nobody expects this behaviour? And why do you reset hiwater_rss, but not hiwater_vm? -- Kirill A. Shutemov