From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752525AbcGALYc (ORCPT ); Fri, 1 Jul 2016 07:24:32 -0400 Received: from mail-wm0-f49.google.com ([74.125.82.49]:38863 "EHLO mail-wm0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752245AbcGALY2 (ORCPT ); Fri, 1 Jul 2016 07:24:28 -0400 Date: Fri, 1 Jul 2016 14:18:46 +0300 From: "Kirill A. Shutemov" To: Byungchul Park Cc: Peter Zijlstra , mingo@kernel.org, linux-kernel@vger.kernel.org, npiggin@suse.de, walken@google.com, ak@suse.de, tglx@inhelltoy.tec.linutronix.de Subject: Re: [RFC 08/12] lockdep: Apply crossrelease to PG_locked lock Message-ID: <20160701111846.GA12284@node.shutemov.name> References: <1466398527-1122-1-git-send-email-byungchul.park@lge.com> <1466398527-1122-9-git-send-email-byungchul.park@lge.com> <20160630130458.GF30154@twins.programming.kicks-ass.net> <20160630232121.GT2279@X58A-UD3R> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160630232121.GT2279@X58A-UD3R> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 01, 2016 at 08:21:21AM +0900, Byungchul Park wrote: > On Thu, Jun 30, 2016 at 03:04:58PM +0200, Peter Zijlstra wrote: > > On Mon, Jun 20, 2016 at 01:55:23PM +0900, Byungchul Park wrote: > > > @@ -215,6 +219,11 @@ struct page { > > > #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS > > > int _last_cpupid; > > > #endif > > > + > > > +#ifdef CONFIG_LOCKDEP_PAGELOCK > > > + struct lockdep_map map; > > > + struct cross_lock xlock; > > > +#endif > > > } > > > > So that's 32+64=96 bytes (CONFIG_LOCK_STAT=n) added to struct page, > > really!? > > Yes... I concerned it at first, but I thought it would be ok since > CONFIG_LOCKDEP_PAGE is a debug feature. Anyway, I will try to reduce > the size of struct cross_lock which is only thing I can do to reduce > it, since we cannot avoid using lockdep_map if we want to make > lock_page() participate in the lockdep play. Please use page_ext instead. With boottime switch to enable. This way we can have this compile-time debug option enabled on more machines without unnecessary runtime overhead. And, please, CC linux-mm next time. -- Kirill A. Shutemov