From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932616AbbJ0RbO (ORCPT ); Tue, 27 Oct 2015 13:31:14 -0400 Received: from mga03.intel.com ([134.134.136.65]:4621 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932367AbbJ0RbN (ORCPT ); Tue, 27 Oct 2015 13:31:13 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,206,1444719600"; d="scan'208";a="672869942" Date: Tue, 27 Oct 2015 11:31:12 -0600 From: Ross Zwisler To: Dan Williams Cc: axboe@fb.com, jack@suse.cz, akpm@linux-foundation.org, linux-nvdimm@ml01.01.org, Dave Hansen , david@fromorbit.com, linux-kernel@vger.kernel.org, willy@linux.intel.com, ross.zwisler@linux.intel.com, hch@lst.de Subject: Re: [PATCH v2 1/5] pmem, dax: clean up clear_pmem() Message-ID: <20151027173112.GA16605@linux.intel.com> References: <20151022171015.38343.72043.stgit@dwillia2-desk3.amr.corp.intel.com> <20151022171021.38343.65959.stgit@dwillia2-desk3.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151022171021.38343.65959.stgit@dwillia2-desk3.amr.corp.intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 22, 2015 at 01:10:21PM -0400, Dan Williams wrote: > Both, __dax_pmd_fault, and clear_pmem() were taking special steps to > clear memory a page at a time to take advantage of non-temporal > clear_page() implementations. However, x86_64 does not use > non-temporal instructions for clear_page(), and arch_clear_pmem() was > always incurring the cost of __arch_wb_cache_pmem(). > > Clean up the assumption that doing clear_pmem() a page at a time is more > performant. > > Cc: Ross Zwisler > Reported-by: Dave Hansen > Signed-off-by: Dan Williams Reviewed-by: Ross Zwisler