From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756406Ab3KFLCS (ORCPT ); Wed, 6 Nov 2013 06:02:18 -0500 Received: from merlin.infradead.org ([205.233.59.134]:51914 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756068Ab3KFLCQ (ORCPT ); Wed, 6 Nov 2013 06:02:16 -0500 Date: Wed, 6 Nov 2013 12:02:00 +0100 From: Peter Zijlstra To: Will Deacon Cc: "Kirill A. Shutemov" , Andrew Morton , "Kirill A. Shutemov" , Ingo Molnar , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "linux-arch@vger.kernel.org" Subject: Re: [PATCH] mm: create a separate slab for page->ptl allocation Message-ID: <20131106110200.GI10651@twins.programming.kicks-ass.net> References: <1382442839-7458-1-git-send-email-kirill.shutemov@linux.intel.com> <20131105150145.734a5dd5b5d455800ebfa0d3@linux-foundation.org> <20131105224217.GC20167@shutemov.name> <20131105155619.021f32eba1ca8f15a73ed4c9@linux-foundation.org> <20131105231310.GE20167@shutemov.name> <20131106103403.GB21074@mudshark.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131106103403.GB21074@mudshark.cambridge.arm.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Nov 06, 2013 at 10:34:03AM +0000, Will Deacon wrote: > FWIW: if the architecture selects ARCH_USE_CMPXCHG_LOCKREF, then a spinlock_t > is 32-bit (assuming that unsigned int is also 32-bit). Egads, talk about fragile. That thing relies on someone actually keeping lib/Kconfig up-to-date.