From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756724AbdCXJgK (ORCPT ); Fri, 24 Mar 2017 05:36:10 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:59545 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751935AbdCXJgE (ORCPT ); Fri, 24 Mar 2017 05:36:04 -0400 Date: Fri, 24 Mar 2017 10:35:55 +0100 From: Heiko Carstens To: Christian Borntraeger Cc: Pavel Tatashin , linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-s390 Subject: Re: [v1 0/5] parallelized "struct page" zeroing References: <1490310113-824438-1-git-send-email-pasha.tatashin@oracle.com> <341568c3-0473-860f-aa20-63723aa40b87@de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <341568c3-0473-860f-aa20-63723aa40b87@de.ibm.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 17032409-0040-0000-0000-0000036E6562 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17032409-0041-0000-0000-00001F674093 Message-Id: <20170324093555.GB5891@osiris> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-03-24_08:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1702020001 definitions=main-1703240084 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Mar 24, 2017 at 09:51:09AM +0100, Christian Borntraeger wrote: > On 03/24/2017 12:01 AM, Pavel Tatashin wrote: > > When deferred struct page initialization feature is enabled, we get a > > performance gain of initializing vmemmap in parallel after other CPUs are > > started. However, we still zero the memory for vmemmap using one boot CPU. > > This patch-set fixes the memset-zeroing limitation by deferring it as well. > > > > Here is example performance gain on SPARC with 32T: > > base > > https://hastebin.com/ozanelatat.go > > > > fix > > https://hastebin.com/utonawukof.go > > > > As you can see without the fix it takes: 97.89s to boot > > With the fix it takes: 46.91 to boot. > > > > On x86 time saving is going to be even greater (proportionally to memory size) > > because there are twice as many "struct page"es for the same amount of memory, > > as base pages are twice smaller. > > Fixing the linux-s390 mailing list email. > This might be useful for s390 as well. Unfortunately only for the fake numa case, since as far as I understand it, parallelization happens only on a node granularity. And since we are usually only having one node... But anyway, it won't hurt to set ARCH_SUPPORTS_DEFERRED_STRUCT_PAGE_INIT on s390 also. I'll do some testing and then we'll see. Pavel, could you please change your patch 5 so it also converts the s390 call sites of vmemmap_alloc_block() so they use VMEMMAP_ZERO instead of 'true' as argument?