Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966735Ab3E2OEI (ORCPT ); Wed, 29 May 2013 10:04:08 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:46249 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966606Ab3E2OED (ORCPT ); Wed, 29 May 2013 10:04:03 -0400 Date: Wed, 29 May 2013 15:03:19 +0100 From: Catalin Marinas To: Vineet Gupta Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Andrew Morton , Mel Gorman , Hugh Dickins , Rik van Riel , David Rientjes , Peter Zijlstra , "linux-arch@vger.kernel.org" , Max Filippov Subject: Re: [PATCH] mm: Fix the TLB range flushed when __tlb_remove_page() runs out of slots Message-ID: <20130529140319.GK17767@MacBook-Pro.local> References: <1369832173-15088-1-git-send-email-vgupta@synopsys.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1369832173-15088-1-git-send-email-vgupta@synopsys.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2185 Lines: 66 On Wed, May 29, 2013 at 01:56:13PM +0100, Vineet Gupta wrote: > zap_pte_range loops from @addr to @end. In the middle, if it runs out of > batching slots, TLB entries needs to be flushed for @start to @interim, > NOT @interim to @end. > > Since ARC port doesn't use page free batching I can't test it myself but > this seems like the right thing to do. > Observed this when working on a fix for the issue at thread: > http://www.spinics.net/lists/linux-arch/msg21736.html > > Signed-off-by: Vineet Gupta > Cc: Andrew Morton > Cc: Mel Gorman > Cc: Hugh Dickins > Cc: Rik van Riel > Cc: David Rientjes > Cc: Peter Zijlstra > Cc: linux-mm@kvack.org > Cc: linux-arch@vger.kernel.org > Cc: Catalin Marinas > Cc: Max Filippov > --- > mm/memory.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/mm/memory.c b/mm/memory.c > index 6dc1882..d9d5fd9 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -1110,6 +1110,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb, > spinlock_t *ptl; > pte_t *start_pte; > pte_t *pte; > + unsigned long range_start = addr; > > again: > init_rss_vec(rss); > @@ -1215,12 +1216,14 @@ again: > force_flush = 0; > > #ifdef HAVE_GENERIC_MMU_GATHER > - tlb->start = addr; > - tlb->end = end; > + tlb->start = range_start; > + tlb->end = addr; > #endif > tlb_flush_mmu(tlb); > - if (addr != end) > + if (addr != end) { > + range_start = addr; > goto again; > + } > } Isn't this code only run if force_flush != 0? force_flush is set to !__tlb_remove_page() and this function always returns 1 on (generic TLB) UP since tlb_fast_mode() is 1. There is no batching on UP with the generic TLB code. -- 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/