Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751527Ab3IPQgE (ORCPT ); Mon, 16 Sep 2013 12:36:04 -0400 Received: from merlin.infradead.org ([205.233.59.134]:55522 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751149Ab3IPQgC (ORCPT ); Mon, 16 Sep 2013 12:36:02 -0400 Date: Mon, 16 Sep 2013 18:35:47 +0200 From: Peter Zijlstra To: Mel Gorman Cc: Rik van Riel , Srikar Dronamraju , Ingo Molnar , Andrea Arcangeli , Johannes Weiner , Linux-MM , LKML Subject: Re: [PATCH 17/50] mm: Do not flush TLB during protection change if !pte_present && !migration_entry Message-ID: <20130916163547.GF9326@twins.programming.kicks-ass.net> References: <1378805550-29949-1-git-send-email-mgorman@suse.de> <1378805550-29949-18-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1378805550-29949-18-git-send-email-mgorman@suse.de> 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 Content-Length: 1269 Lines: 34 On Tue, Sep 10, 2013 at 10:31:57AM +0100, Mel Gorman wrote: > NUMA PTE scanning is expensive both in terms of the scanning itself and > the TLB flush if there are any updates. Currently non-present PTEs are > accounted for as an update and incurring a TLB flush where it is only > necessary for anonymous migration entries. This patch addresses the > problem and should reduce TLB flushes. > > Signed-off-by: Mel Gorman > --- > mm/mprotect.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/mprotect.c b/mm/mprotect.c > index 1f9b54b..1e9cef0 100644 > --- a/mm/mprotect.c > +++ b/mm/mprotect.c > @@ -109,8 +109,9 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, > make_migration_entry_read(&entry); > set_pte_at(mm, addr, pte, > swp_entry_to_pte(entry)); > + > + pages++; > } > - pages++; > } > } while (pte++, addr += PAGE_SIZE, addr != end); > arch_leave_lazy_mmu_mode(); Should we fold this into patch 7 ? -- 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/