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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0DBE0C433F5 for ; Wed, 13 Apr 2022 16:30:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 96CD56B0074; Wed, 13 Apr 2022 12:30:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 91F636B0075; Wed, 13 Apr 2022 12:30:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7E62F6B0078; Wed, 13 Apr 2022 12:30:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0001.hostedemail.com [216.40.44.1]) by kanga.kvack.org (Postfix) with ESMTP id 6E7F96B0074 for ; Wed, 13 Apr 2022 12:30:02 -0400 (EDT) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 25095A7C49 for ; Wed, 13 Apr 2022 16:30:02 +0000 (UTC) X-FDA: 79352392644.23.785B369 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf06.hostedemail.com (Postfix) with ESMTP id 2297F180008 for ; Wed, 13 Apr 2022 16:30:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=5bxNeFCNqtSiVLbQzdDfEBDhH6rbLnTelph4miGTqcI=; b=ZDD2+/SPzOdS7gIGaIEN0WYdw2 csM5cEpfpVa4zPMV6qQMG16FX8GAc8H1eGmVn0mAyKrCmXot6li/ApLCBGfTBvms7T8/IlTqWq2rd cX+7Jh1S0o7VKL2iQxM+0BNlZHKrUACHDPR7gs2zVuDVpyoevItTU8TJemXQCr41HAh1Hpim+LNfs yY8nXcbyB2ub4RiGkg1g+qHiyg/tnrreZACe8kSk14FDiMf4TUFKJaafxLONmflJFnNsSOAxNDaBV JGQCMma/H2xQN3MxEre5D8cDJ5NZrCjJMYzaLHVaYF6Mwj1pYuFfulzY3NdBoTnz/PSqQXCy5o/PP jjAo4hOw==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1nefsQ-00EOn1-Uf; Wed, 13 Apr 2022 16:29:55 +0000 Date: Wed, 13 Apr 2022 17:29:54 +0100 From: Matthew Wilcox To: Anshuman Khandual Cc: inux-mm@kvack.org, Andrew Morton , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Peter Zijlstra , Arnd Bergmann , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] tlb/hugetlb: Add framework to handle PGDIR_SIZE HugeTLB pages Message-ID: References: <20220413100714.509888-1-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220413100714.509888-1-anshuman.khandual@arm.com> X-Rspam-User: Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b="ZDD2+/SP"; spf=none (imf06.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 2297F180008 X-Stat-Signature: r75cmcn7xmbs6gwtgsiaca7yrww4zw1e X-HE-Tag: 1649867400-941080 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 Wed, Apr 13, 2022 at 03:37:14PM +0530, Anshuman Khandual wrote: > Change tlb_remove_huge_tlb_entry() to accommodate larger PGDIR_SIZE HugeTLB > pages via adding a new helper tlb_flush_pgd_range(). While here also update > struct mmu_gather as required, that is add a new member cleared_pgds. Is this just completionist junk, or are there really CPUs that support PGDIR sized pages? We already have support for p4d (512GB), even though at least Intel don't support pages larger than 1GB. I think the largest size page I've heard of is 16GB on POWER. PGDIR_SIZE would be 256TB on x86 which just seems ludicrous to be talking about supporting. > --- > This applies on v5.18-rc2, some earlier context could be found here > > https://lore.kernel.org/all/20220406112124.GD2731@worktop.programming.kicks-ass.net/ Read it, doesn't talk about any real users of this.