From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f197.google.com (mail-wr0-f197.google.com [209.85.128.197]) by kanga.kvack.org (Postfix) with ESMTP id 78C4F6B0033 for ; Fri, 6 Oct 2017 08:11:48 -0400 (EDT) Received: by mail-wr0-f197.google.com with SMTP id k7so12502076wre.5 for ; Fri, 06 Oct 2017 05:11:48 -0700 (PDT) Received: from smtp-out4.electric.net (smtp-out4.electric.net. [192.162.216.194]) by mx.google.com with ESMTPS id k5si1782321edd.18.2017.10.06.05.11.47 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 06 Oct 2017 05:11:47 -0700 (PDT) From: David Laight Subject: RE: [PATCH v10 09/10] mm: stop zeroing memory during allocation in vmemmap Date: Fri, 6 Oct 2017 12:11:42 +0000 Message-ID: <063D6719AE5E284EB5DD2968C1650D6DD008BB4D@AcuExch.aculab.com> References: <20171005211124.26524-1-pasha.tatashin@oracle.com> <20171005211124.26524-10-pasha.tatashin@oracle.com> <063D6719AE5E284EB5DD2968C1650D6DD008BA85@AcuExch.aculab.com> <20171006114729.fexwklupkhyxdpt3@dhcp22.suse.cz> In-Reply-To: <20171006114729.fexwklupkhyxdpt3@dhcp22.suse.cz> Content-Language: en-US Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: 'Michal Hocko' Cc: 'Pavel Tatashin' , "linux-kernel@vger.kernel.org" , "sparclinux@vger.kernel.org" , "linux-mm@kvack.org" , "linuxppc-dev@lists.ozlabs.org" , "linux-s390@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "x86@kernel.org" , "kasan-dev@googlegroups.com" , "borntraeger@de.ibm.com" , "heiko.carstens@de.ibm.com" , "davem@davemloft.net" , "willy@infradead.org" , "ard.biesheuvel@linaro.org" , "mark.rutland@arm.com" , "will.deacon@arm.com" , "catalin.marinas@arm.com" , "sam@ravnborg.org" , "mgorman@techsingularity.net" , "steven.sistare@oracle.com" , "daniel.m.jordan@oracle.com" , "bob.picco@oracle.com" From: Michal Hocko > Sent: 06 October 2017 12:47 > On Fri 06-10-17 11:10:14, David Laight wrote: > > From: Pavel Tatashin > > > Sent: 05 October 2017 22:11 > > > vmemmap_alloc_block() will no longer zero the block, so zero memory > > > at its call sites for everything except struct pages. Struct page me= mory > > > is zero'd by struct page initialization. > > > > It seems dangerous to change an allocator to stop zeroing memory. > > It is probably saver to add a new function that doesn't zero > > the memory and use that is the places where you don't want it > > to be zeroed. >=20 > Not sure what you mean. memblock_virt_alloc_try_nid_raw is a new > function which doesn't zero out... You should probably leave vmemap_alloc_block() zeroing the memory so that existing alls don't have to be changed - apart from the ones you are explicitly optimising. David -- 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/ . Don't email: email@kvack.org