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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 autolearn=no 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 C8068C54E4A for ; Tue, 12 May 2020 15:13:40 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9526020730 for ; Tue, 12 May 2020 15:13:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9526020730 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=goodmis.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 387039000C6; Tue, 12 May 2020 11:13:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 31078900036; Tue, 12 May 2020 11:13:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 226AF9000C6; Tue, 12 May 2020 11:13:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0123.hostedemail.com [216.40.44.123]) by kanga.kvack.org (Postfix) with ESMTP id 06CDC900036 for ; Tue, 12 May 2020 11:13:38 -0400 (EDT) Received: from smtpin03.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id B4727181AEF1D for ; Tue, 12 May 2020 15:13:37 +0000 (UTC) X-FDA: 76808411274.03.steel92_3c9ec61efd733 X-HE-Tag: steel92_3c9ec61efd733 X-Filterd-Recvd-Size: 2633 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf41.hostedemail.com (Postfix) with ESMTP for ; Tue, 12 May 2020 15:13:36 +0000 (UTC) Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id E42592054F; Tue, 12 May 2020 15:13:33 +0000 (UTC) Date: Tue, 12 May 2020 11:13:32 -0400 From: Steven Rostedt To: Joerg Roedel Cc: Andy Lutomirski , Andy Lutomirski , Peter Zijlstra , Joerg Roedel , X86 ML , "H. Peter Anvin" , Dave Hansen , "Rafael J. Wysocki" , Arnd Bergmann , Andrew Morton , Vlastimil Babka , Michal Hocko , LKML , Linux ACPI , linux-arch , Linux-MM Subject: Re: [RFC PATCH 0/7] mm: Get rid of vmalloc_sync_(un)mappings() Message-ID: <20200512111332.24f5cd7a@gandalf.local.home> In-Reply-To: <20200512150250.GC8135@suse.de> References: <20200511191414.GY8135@suse.de> <8D6745B7-0EC2-4FCC-B6FC-E7E1557EB18E@amacapital.net> <20200512150250.GC8135@suse.de> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, 12 May 2020 17:02:50 +0200 Joerg Roedel wrote: > On Mon, May 11, 2020 at 12:36:19PM -0700, Andy Lutomirski wrote: > > I=E2=80=99m guessing the right solution is either your series or your s= eries > > plus preallocation on 64-bit. I=E2=80=99m just grumpy about it... =20 >=20 > Okay, so we can do the pre-allocation when it turns out the pgd_list > lock-times become a problem on x86-64. The tracking code in vmalloc.c is > needed anyway for 32-bit and there is no reason why 64-bit shouldn't use > it as well for now. > I don't think that taking the lock _will_ be a problem, as it is only > taken when a new PGD/P4D entry is populated. And it is pretty unlikely > that a system will populate all 64 of them, with 4-level paging each of > these entries will map 512GB of address space. But if I am wrong here > pre-allocating is still an option. >=20 256TB of RAM isn't too far in the future ;-) -- Steve