From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta12.messagelabs.com (mail6.bemta12.messagelabs.com [216.82.250.247]) by kanga.kvack.org (Postfix) with ESMTP id 22543900146 for ; Wed, 10 Aug 2011 20:17:01 -0400 (EDT) Message-ID: <4E431F62.5030704@redhat.com> Date: Wed, 10 Aug 2011 20:16:34 -0400 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 2 of 3] mremap: avoid sending one IPI per page References: In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: aarcange@redhat.com Cc: linux-mm@kvack.org, Mel Gorman , Johannes Weiner , Hugh Dickins On 08/06/2011 12:58 PM, aarcange@redhat.com wrote: > From: Andrea Arcangeli > > This replaces ptep_clear_flush() with ptep_get_and_clear() and a single > flush_tlb_range() at the end of the loop, to avoid sending one IPI for each > page. > > The mmu_notifier_invalidate_range_start/end section is enlarged accordingly but > this is not going to fundamentally change things. It was more by accident that > the region under mremap was for the most part still available for secondary > MMUs: the primary MMU was never allowed to reliably access that region for the > duration of the mremap (modulo trapping SIGSEGV on the old address range which > sounds unpractical and flakey). If users wants secondary MMUs not to lose > access to a large region under mremap Userspace programs do not get reliable access to memory that is currently being mremapped. This patch does not change that situation in the least. > Signed-off-by: Andrea Arcangeli Acked-by: Rik van Riel -- All rights reversed -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org