Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753388AbdDGGPk (ORCPT ); Fri, 7 Apr 2017 02:15:40 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:53024 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752691AbdDGGPd (ORCPT ); Fri, 7 Apr 2017 02:15:33 -0400 From: "Aneesh Kumar K.V" To: Heiko Carstens , Pavel Tatashin Cc: linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, borntraeger@de.ibm.com, davem@davemloft.net, willy@infradead.org Subject: Re: [v2 5/5] mm: teach platforms not to zero struct pages memory In-Reply-To: <20170327060032.GB5092@osiris> References: <1490383192-981017-1-git-send-email-pasha.tatashin@oracle.com> <1490383192-981017-6-git-send-email-pasha.tatashin@oracle.com> <20170327060032.GB5092@osiris> Date: Fri, 07 Apr 2017 11:45:23 +0530 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-MML: disable x-cbid: 17040706-0024-0000-0000-000003C70AC0 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17040706-0025-0000-0000-000011453A68 Message-Id: <87bms8rbes.fsf@skywalker.in.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-04-07_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1702020001 definitions=main-1704070056 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2373 Lines: 58 Heiko Carstens writes: > On Fri, Mar 24, 2017 at 03:19:52PM -0400, Pavel Tatashin wrote: >> If we are using deferred struct page initialization feature, most of >> "struct page"es are getting initialized after other CPUs are started, and >> hence we are benefiting from doing this job in parallel. However, we are >> still zeroing all the memory that is allocated for "struct pages" using the >> boot CPU. This patch solves this problem, by deferring zeroing "struct >> pages" to only when they are initialized. >> >> Signed-off-by: Pavel Tatashin >> Reviewed-by: Shannon Nelson >> --- >> arch/powerpc/mm/init_64.c | 2 +- >> arch/s390/mm/vmem.c | 2 +- >> arch/sparc/mm/init_64.c | 2 +- >> arch/x86/mm/init_64.c | 2 +- >> 4 files changed, 4 insertions(+), 4 deletions(-) >> >> diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c >> index eb4c270..24faf2d 100644 >> --- a/arch/powerpc/mm/init_64.c >> +++ b/arch/powerpc/mm/init_64.c >> @@ -181,7 +181,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) >> if (vmemmap_populated(start, page_size)) >> continue; >> >> - p = vmemmap_alloc_block(page_size, node, true); >> + p = vmemmap_alloc_block(page_size, node, VMEMMAP_ZERO); >> if (!p) >> return -ENOMEM; >> >> diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c >> index 9c75214..ffe9ba1 100644 >> --- a/arch/s390/mm/vmem.c >> +++ b/arch/s390/mm/vmem.c >> @@ -252,7 +252,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node) >> void *new_page; >> >> new_page = vmemmap_alloc_block(PMD_SIZE, node, >> - true); >> + VMEMMAP_ZERO); >> if (!new_page) >> goto out; >> pmd_val(*pm_dir) = __pa(new_page) | sgt_prot; > > s390 has two call sites that need to be converted, like you did in one of > your previous patches. The same seems to be true for powerpc, unless there > is a reason to not convert them? > vmemmap_list_alloc is not really struct page allocation right ? We are just allocating memory to be used as vmemmmap_backing. But considering we are updating all the three elements of the sturct, we can avoid that memset . But instead of VMEMMAP_ZERO we can just pass false in that case ? -aneesh