From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E349DC43218 for ; Mon, 10 Jun 2019 21:37:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B9A622086A for ; Mon, 10 Jun 2019 21:37:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390076AbfFJVhC (ORCPT ); Mon, 10 Jun 2019 17:37:02 -0400 Received: from mx2.suse.de ([195.135.220.15]:38318 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2389193AbfFJVhC (ORCPT ); Mon, 10 Jun 2019 17:37:02 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 720E7AAA8; Mon, 10 Jun 2019 21:37:00 +0000 (UTC) Message-ID: <1560202615.3312.6.camel@suse.de> Subject: Re: [v7 PATCH 1/2] mm: vmscan: remove double slab pressure by inc'ing sc->nr_scanned From: Oscar Salvador To: Yang Shi , ying.huang@intel.com, hannes@cmpxchg.org, mhocko@suse.com, mgorman@techsingularity.net, kirill.shutemov@linux.intel.com, josef@toxicpanda.com, hughd@google.com, shakeelb@google.com, hdanton@sina.com, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Date: Mon, 10 Jun 2019 23:36:55 +0200 In-Reply-To: <1559025859-72759-1-git-send-email-yang.shi@linux.alibaba.com> References: <1559025859-72759-1-git-send-email-yang.shi@linux.alibaba.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2019-05-28 at 14:44 +0800, Yang Shi wrote: > The commit 9092c71bb724 ("mm: use sc->priority for slab shrink > targets") > has broken up the relationship between sc->nr_scanned and slab > pressure. > The sc->nr_scanned can't double slab pressure anymore. So, it sounds > no > sense to still keep sc->nr_scanned inc'ed. Actually, it would > prevent > from adding pressure on slab shrink since excessive sc->nr_scanned > would > prevent from scan->priority raise. Hi Yang, I might be misunderstanding this, but did you mean "prevent from scan- priority decreasing"? I guess we are talking about balance_pgdat(), and in case kswapd_shrink_node() returns true (it means we have scanned more than we had to reclaim), raise_priority becomes false, and this does not let sc->priority to be decreased, which has the impact that less pages will be reclaimed the next round. Sorry for bugging here, I just wanted to see if I got this right. -- Oscar Salvador SUSE L3