From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757739Ab2HPXMt (ORCPT ); Thu, 16 Aug 2012 19:12:49 -0400 Received: from mga01.intel.com ([192.55.52.88]:29322 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755488Ab2HPXMr (ORCPT ); Thu, 16 Aug 2012 19:12:47 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.77,781,1336374000"; d="scan'208";a="203082086" Date: Thu, 16 Aug 2012 16:12:47 -0700 From: Andi Kleen To: Andrea Arcangeli Cc: Andrew Morton , "Kirill A. Shutemov" , linux-mm@kvack.org, "H. Peter Anvin" , linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: Re: [PATCH, RFC 0/9] Introduce huge zero page Message-ID: <20120816231247.GA4461@tassilo.jf.intel.com> References: <1344503300-9507-1-git-send-email-kirill.shutemov@linux.intel.com> <20120816122023.c0e9bbc0.akpm@linux-foundation.org> <20120816194024.GP11188@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120816194024.GP11188@redhat.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 > Because this is done the right way (i.e. to allocate an hugepage at > the first wp fault, and to fallback exclusively if compaction fails) > it will help much less than the 4k zero pages if the zero pages are The main benefit is that you have a zero page with THP enabled. So it lowers the cost of having THP on (for workloads that benefit from a zero page) -Andi -- ak@linux.intel.com -- Speaking for myself only