Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751670AbdIAJVO (ORCPT ); Fri, 1 Sep 2017 05:21:14 -0400 Received: from mx2.suse.de ([195.135.220.15]:48534 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751511AbdIAJVN (ORCPT ); Fri, 1 Sep 2017 05:21:13 -0400 Date: Fri, 1 Sep 2017 11:21:08 +0200 From: Michal Hocko To: Konstantin Khlebnikov Cc: Kyeongdon Kim , akpm@linux-foundation.org, sfr@canb.auug.org.au, ying.huang@intel.com, vbabka@suse.cz, hannes@cmpxchg.org, xieyisheng1@huawei.com, luto@kernel.org, shli@fb.com, mgorman@techsingularity.net, hillf.zj@alibaba-inc.com, kemi.wang@intel.com, rientjes@google.com, bigeasy@linutronix.de, iamjoonsoo.kim@lge.com, bongkyu.kim@lge.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH] mm/vmstats: add counters for the page frag cache Message-ID: <20170901092108.lb3jla2hpczjvrh5@dhcp22.suse.cz> References: <1504222631-2635-1-git-send-email-kyeongdon.kim@lge.com> <50592560-af4d-302c-c0bc-1e854e35139d@yandex-team.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50592560-af4d-302c-c0bc-1e854e35139d@yandex-team.ru> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 523 Lines: 13 On Fri 01-09-17 12:12:36, Konstantin Khlebnikov wrote: > IMHO that's too much counters. > Per-node NR_FRAGMENT_PAGES should be enough for guessing what's going on. > Perf probes provides enough features for furhter debugging. I would tend to agree. Adding a counter based on a single debugging instance sounds like an overkill to me. Counters should be pretty cheep but this is way too specialized API to export to the userspace. We have other interfaces to debug memory leaks like page_owner. -- Michal Hocko SUSE Labs