From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id 3830582F64 for ; Wed, 21 Dec 2016 21:07:59 -0500 (EST) Received: by mail-pg0-f71.google.com with SMTP id b1so421514729pgc.5 for ; Wed, 21 Dec 2016 18:07:59 -0800 (PST) Received: from mail-pg0-x241.google.com (mail-pg0-x241.google.com. [2607:f8b0:400e:c05::241]) by mx.google.com with ESMTPS id f5si28816440plm.37.2016.12.21.18.07.58 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 21 Dec 2016 18:07:58 -0800 (PST) Received: by mail-pg0-x241.google.com with SMTP id w68so12251900pgw.3 for ; Wed, 21 Dec 2016 18:07:58 -0800 (PST) Date: Thu, 22 Dec 2016 12:07:40 +1000 From: Nicholas Piggin Subject: Re: [RFC][PATCH] make global bitlock waitqueues per-node Message-ID: <20161222120740.024eba5a@roar.ozlabs.ibm.com> In-Reply-To: References: <20161219225826.F8CB356F@viggo.jf.intel.com> <156a5b34-ad3b-d0aa-83c9-109b366c1bdf@linux.intel.com> <20161221080931.GQ3124@twins.programming.kicks-ass.net> <20161221083247.GW3174@twins.programming.kicks-ass.net> <20161222043331.31aab9cc@roar.ozlabs.ibm.com> <20161222050130.49d93982@roar.ozlabs.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Linus Torvalds Cc: Peter Zijlstra , Dave Hansen , Bob Peterson , Linux Kernel Mailing List , Steven Whitehouse , Andrew Lutomirski , Andreas Gruenbacher , Mel Gorman , linux-mm , Hugh Dickins On Wed, 21 Dec 2016 11:50:49 -0800 Linus Torvalds wrote: > On Wed, Dec 21, 2016 at 11:01 AM, Nicholas Piggin wrote: > > Peter's patch is less code and in that regard a bit nicer. I tried > > going that way once, but I just thought it was a bit too sloppy to > > do nicely with wait bit APIs. > > So I have to admit that when I read through your and PeterZ's patches > back-to-back, yours was easier to understand. > > PeterZ's is smaller but kind of subtle. The whole "return zero from > lock_page_wait() and go around again" and the locking around that > isn't exactly clear. In contrast, yours has the obvious waitqueue > spinlock. > > I'll think about it. And yes, it would be good to have more testing, > but at the same time xmas is imminent, and waiting around too much > isn't going to help either.. Sure. Let's see if Dave and Mel get a chance to do some testing. It might be a squeeze before Christmas. I realize we're going to fix it anyway so on one hand might as well get something in. On the other I didn't want to add a subtle bug then have everyone go on vacation. How about I send up the page flag patch by Friday and that can bake while the main patch gets more testing / review? Thanks, Nick -- 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