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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY 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 AAAF8C43387 for ; Tue, 18 Dec 2018 23:43:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 81D7D21873 for ; Tue, 18 Dec 2018 23:43:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727594AbeLRXnU (ORCPT ); Tue, 18 Dec 2018 18:43:20 -0500 Received: from out30-133.freemail.mail.aliyun.com ([115.124.30.133]:44582 "EHLO out30-133.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727457AbeLRXnT (ORCPT ); Tue, 18 Dec 2018 18:43:19 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R201e4;CH=green;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07487;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=7;SR=0;TI=SMTPD_---0TG59XVS_1545176588; Received: from US-143344MP.local(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TG59XVS_1545176588) by smtp.aliyun-inc.com(127.0.0.1); Wed, 19 Dec 2018 07:43:12 +0800 Subject: Re: [RFC PATCH 1/2] mm: swap: check if swap backing device is congested or not To: Tim Chen , ying.huang@intel.com, tim.c.chen@intel.com, minchan@kernel.org, Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <1545115948-25467-1-git-send-email-yang.shi@linux.alibaba.com> <6a51d47a-b87f-b0f1-4dae-843730dba698@linux.intel.com> From: Yang Shi Message-ID: <03462367-3f75-4907-8c5e-526a919e5cf3@linux.alibaba.com> Date: Tue, 18 Dec 2018 15:43:07 -0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <6a51d47a-b87f-b0f1-4dae-843730dba698@linux.intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/18/18 11:29 AM, Tim Chen wrote: > On 12/17/18 10:52 PM, Yang Shi wrote: > >> diff --git a/mm/swap_state.c b/mm/swap_state.c >> index fd2f21e..7cc3c29 100644 >> --- a/mm/swap_state.c >> +++ b/mm/swap_state.c >> @@ -538,11 +538,15 @@ struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, >> bool do_poll = true, page_allocated; >> struct vm_area_struct *vma = vmf->vma; >> unsigned long addr = vmf->address; >> + struct inode *inode = si->swap_file->f_mapping->host; >> >> mask = swapin_nr_pages(offset) - 1; >> if (!mask) >> goto skip; >> > Shmem will also be using this function and I don't think the inode_read_congested > logic is relevant for that case. IMHO, shmem is also relevant. As long as it is trying to readahead from swap, it should check if the underlying device is busy or not regardless of shmem or anon page. Just like mem_cgroup_try_charge_delay(), which throttles swap rate for both swap page fault and shmem. Thanks, Yang > > So probably change the check to > > if (swp_type(entry) < nr_swapfiles && > inode_read_congested(si->swap_file->f_mapping->host)) > goto skip; > >> + if (inode_read_congested(inode)) >> + goto skip; >> + >> do_poll = false; >> /* Read a page_cluster sized and aligned cluster around offset. */ >> start_offset = offset & ~mask; >> > Thanks. > > Tim