From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F19EDC5CFEB for ; Wed, 11 Jul 2018 12:48:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B20172089B for ; Wed, 11 Jul 2018 12:48:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B20172089B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732562AbeGKMwO (ORCPT ); Wed, 11 Jul 2018 08:52:14 -0400 Received: from mx2.suse.de ([195.135.220.15]:37932 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726457AbeGKMwO (ORCPT ); Wed, 11 Jul 2018 08:52:14 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 738DCADAB; Wed, 11 Jul 2018 12:48:02 +0000 (UTC) Date: Wed, 11 Jul 2018 14:48:01 +0200 From: Michal Hocko To: Cannon Matthews Cc: Andrew Morton , Mike Kravetz , Nadia Yvette Chambers , linux-mm@kvack.org, linux-kernel@vger.kernel.org, andreslc@google.com, pfeiner@google.com, dmatlack@google.com, gthelen@google.com Subject: Re: [PATCH] mm: hugetlb: don't zero 1GiB bootmem pages. Message-ID: <20180711124801.GO20050@dhcp22.suse.cz> References: <20180710184903.68239-1-cannonmatthews@google.com> <20180711124711.GA20172@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180711124711.GA20172@dhcp22.suse.cz> User-Agent: Mutt/1.10.0 (2018-05-17) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 11-07-18 14:47:11, Michal Hocko wrote: > On Tue 10-07-18 11:49:03, Cannon Matthews wrote: > > When using 1GiB pages during early boot, use the new > > memblock_virt_alloc_try_nid_raw() function to allocate memory without > > zeroing it. Zeroing out hundreds or thousands of GiB in a single core > > memset() call is very slow, and can make early boot last upwards of > > 20-30 minutes on multi TiB machines. > > > > To be safe, still zero the first sizeof(struct boomem_huge_page) bytes > > since this is used a temporary storage place for this info until > > gather_bootmem_prealloc() processes them later. > > > > The rest of the memory does not need to be zero'd as the hugetlb pages > > are always zero'd on page fault. > > > > Tested: Booted with ~3800 1G pages, and it booted successfully in > > roughly the same amount of time as with 0, as opposed to the 25+ > > minutes it would take before. > > The patch makes perfect sense to me. I wasn't even aware that it > zeroying memblock allocation. Thanks for spotting this and fixing it. > > > Signed-off-by: Cannon Matthews > > I just do not think we need to to zero huge_bootmem_page portion of it. > It should be sufficient to INIT_LIST_HEAD before list_add. We do > initialize the rest explicitly already. Forgot to mention that after that is addressed you can add Acked-by: Michal Hocko -- Michal Hocko SUSE Labs