From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752819AbcG2MZY (ORCPT ); Fri, 29 Jul 2016 08:25:24 -0400 Received: from mail-yw0-f195.google.com ([209.85.161.195]:36553 "EHLO mail-yw0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751123AbcG2MZT (ORCPT ); Fri, 29 Jul 2016 08:25:19 -0400 Date: Fri, 29 Jul 2016 08:25:16 -0400 From: Tejun Heo To: Saeed Mahameed Cc: Bhaktipriya Shridhar , Saeed Mahameed , Matan Barak , Leon Romanovsky , Linux Netdev List , linux-rdma@vger.kernel.org, linux-kernel Subject: Re: [RFC] net/mlx5_core/en_main: Remove deprecated create_workqueue Message-ID: <20160729122516.GH2542@mtj.duckdns.org> References: <20160727061229.GA16943@Karyakshetra> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.6.2 (2016-07-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Fri, Jul 29, 2016 at 01:30:05AM +0300, Saeed Mahameed wrote: > > Are the workitems being used on a memory reclaim path? > > do you mean they need to allocate memory ? It's a bit convoluted. A workqueue needs WQ_MEM_RECLAIM flag to be guaranteed forward progress under memory pressure, so any workqueue which may be depended upon during memory reclaim should have the flag set; otherwise, the system can deadlock (try to reclaim memory, hits the wq which can't make forward progress due to lack of memory). For network devices, the requirement comes from block-over-network or nfs which can be involved in memory reclaim. Thanks. -- tejun