From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f197.google.com (mail-pf0-f197.google.com [209.85.192.197]) by kanga.kvack.org (Postfix) with ESMTP id 146F86B007E for ; Thu, 2 Jun 2016 20:48:50 -0400 (EDT) Received: by mail-pf0-f197.google.com with SMTP id s73so81289351pfs.0 for ; Thu, 02 Jun 2016 17:48:50 -0700 (PDT) Received: from smtpbgsg2.qq.com (smtpbgsg2.qq.com. [54.254.200.128]) by mx.google.com with ESMTPS id zh6si1937232pab.23.2016.06.02.17.48.48 for (version=TLS1 cipher=AES128-SHA bits=128/128); Thu, 02 Jun 2016 17:48:49 -0700 (PDT) Subject: Re: [PATCH] mm: Introduce dedicated WQ_MEM_RECLAIM workqueue to do lru_add_drain_all References: <1464853731-8599-1-git-send-email-shhuiw@foxmail.com> <20160602143925.GJ14868@mtj.duckdns.org> From: Wang Sheng-Hui Message-ID: Date: Fri, 3 Jun 2016 08:48:37 +0800 MIME-Version: 1.0 In-Reply-To: <20160602143925.GJ14868@mtj.duckdns.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: keith.busch@intel.com, peterz@infradead.org, treding@nvidia.com, mingo@redhat.com, akpm@linux-foundation.org, linux-mm@kvack.org Tejun, On 6/2/2016 10:39 PM, Tejun Heo wrote: > On Thu, Jun 02, 2016 at 03:48:51PM +0800, Wang Sheng-Hui wrote: >> +static int __init lru_init(void) >> +{ >> + lru_add_drain_wq = alloc_workqueue("lru-add-drain", >> + WQ_MEM_RECLAIM | WQ_UNBOUND, 0); > Why is it unbound? Sorry, I just pasted from other wq create statement. WQ_MEM_RECLAIM is the key. Will drop WQ_UNBOUND in new version patch. >> + if (WARN(!lru_add_drain_wq, >> + "Failed to create workqueue lru_add_drain_wq")) >> + return -ENOMEM; > I don't think we need an explicit warn here. Doesn't error return > from an init function trigger boot failure anyway? Will drop the warn and return -ENOMEM directly on failure. >> + return 0; >> +} >> +early_initcall(lru_init); >> + >> void lru_add_drain_all(void) >> { >> static DEFINE_MUTEX(lock); >> static struct cpumask has_work; >> int cpu; >> >> + struct workqueue_struct *lru_wq = lru_add_drain_wq ?: system_wq; >> + >> + WARN_ONCE(!lru_add_drain_wq, >> + "Use system_wq to do lru_add_drain_all()"); > Ditto. The system is crashing for sure. What's the point of this > warning? It's for above warn failure. Will crash instead of falling back to system_wq > > Thanks. > Thanks, Sheng-Hui -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org