From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qa0-f42.google.com (mail-qa0-f42.google.com [209.85.216.42]) by kanga.kvack.org (Postfix) with ESMTP id 2F03A6B0035 for ; Tue, 6 May 2014 16:30:11 -0400 (EDT) Received: by mail-qa0-f42.google.com with SMTP id j5so19602qaq.15 for ; Tue, 06 May 2014 13:30:10 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org. [2001:1868:205::9]) by mx.google.com with ESMTPS id v9si5727126qar.105.2014.05.06.13.30.10 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 06 May 2014 13:30:10 -0700 (PDT) Date: Tue, 6 May 2014 22:30:06 +0200 From: Peter Zijlstra Subject: Re: [PATCH 17/17] mm: filemap: Avoid unnecessary barries and waitqueue lookup in unlock_page fastpath Message-ID: <20140506203006.GF1429@laptop.programming.kicks-ass.net> References: <1398933888-4940-1-git-send-email-mgorman@suse.de> <1398933888-4940-18-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1398933888-4940-18-git-send-email-mgorman@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Linux-MM , Linux-FSDevel , Johannes Weiner , Vlastimil Babka , Jan Kara , Michal Hocko , Hugh Dickins , Linux Kernel On Thu, May 01, 2014 at 09:44:48AM +0100, Mel Gorman wrote: > +/* > + * If PageWaiters was found to be set at unlock time, __wake_page_waiters > + * should be called to actually perform the wakeup of waiters. > + */ > +static inline void __wake_page_waiters(struct page *page) > +{ > + ClearPageWaiters(page); -ENOCOMMENT barriers should always come with a comment that explain the memory ordering and reference the pairing barrier. Also, FWIW, there's a mass rename queued for .16 that'll make this: smp_mb__after_atomic(); but for now it will also still provide the old names with a __deprecated tag on, so no real harm. > + smp_mb__after_clear_bit(); > + wake_up_page(page, PG_locked); > +} -- 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