Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030337Ab2EQRB4 (ORCPT ); Thu, 17 May 2012 13:01:56 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:51452 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965203Ab2EQRBx (ORCPT ); Thu, 17 May 2012 13:01:53 -0400 Date: Thu, 17 May 2012 18:01:34 +0100 From: Catalin Marinas To: Peter Zijlstra Cc: Russell King , Paul Mundt , Andrea Arcangeli , Thomas Gleixner , Rik van Riel , Ingo Molnar , "akpm@linux-foundation.org" , Linus Torvalds , "linux-kernel@vger.kernel.org" , "linux-arch@vger.kernel.org" , "linux-mm@kvack.org" , Benjamin Herrenschmidt , David Miller , Hugh Dickins , Mel Gorman , Nick Piggin , Chris Metcalf , Martin Schwidefsky Subject: Re: [RFC][PATCH 4/6] arm, mm: Convert arm to generic tlb Message-ID: <20120517170134.GC18593@arm.com> References: <20110302175928.022902359@chello.nl> <20110302180259.109909335@chello.nl> <20120517030551.GA11623@linux-sh.org> <20120517093022.GA14666@arm.com> <20120517095124.GN23420@flint.arm.linux.org.uk> <1337254086.4281.26.camel@twins> <20120517160012.GB18593@arm.com> <1337271884.4281.46.camel@twins> <1337272396.4281.48.camel@twins> <1337273053.4281.50.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1337273053.4281.50.camel@twins> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1661 Lines: 34 On Thu, May 17, 2012 at 05:44:13PM +0100, Peter Zijlstra wrote: > On Thu, 2012-05-17 at 18:33 +0200, Peter Zijlstra wrote: > > On Thu, 2012-05-17 at 18:24 +0200, Peter Zijlstra wrote: > > > On Thu, 2012-05-17 at 17:00 +0100, Catalin Marinas wrote: > > > > BTW, looking at your tlb-unify branch, does tlb_remove_table() call > > > > tlb_flush/tlb_flush_mmu before freeing the tables? I can only see > > > > tlb_remove_page() doing this. On ARM, even UP, we need the TLB flushing > > > > after clearing the pmd and before freeing the pte page table (and > > > > ideally doing it less often than at every pte_free_tlb() call). > > > > > > No I don't think it does, so far the only archs using the RCU stuff are > > > ppc,sparc and s390 and none of those needed that (Xen might join them > > > soon though). But I will have to look and consider this more carefully. > > > I 'lost' most of the ppc/sparc/s390 details from memory to say this with > > > any certainty. > > > > Hmm, no, thinking more that does indeed sounds strange, I'll still have > > to consider it more carefully, but I think you might have found a bug > > there. > > So the RCU code can from ppc in commit > 267239116987d64850ad2037d8e0f3071dc3b5ce, which has similar behaviour. > Also I suspect the mm_users < 2 test will be incorrect for ARM since > even the one user can be concurrent with your speculation engine. That's correct. -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/