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=-3.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,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 C64F1C43387 for ; Wed, 16 Jan 2019 12:34:34 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8F7E720651 for ; Wed, 16 Jan 2019 12:34:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="bQcVPthd" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8F7E720651 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=qK7q8/hNi7AuBD/W9uYT03J+Dq5DVW6yCoyo2/PJGGI=; b=bQcVPthdravbol DF96XESQprgNmlE4qGxkBEiLT+S0TCDqt7YcWFd+iGCbU6SNAbQMMzurZt+VD1R9d0KjtLWdY7cJD mLDxNx4cu6lRBhddm1camrvdqPzB4OF9UOBnxTLSegUP4/UIdDQdv3tP4mYGIuhnaxM+tinbGpSm9 uMVzPO7W0FdaGeRWLbtbQXhamCpjtpvbhNZ0hwrr/OZMcWx1L2KUB+e8Rc71juzBaBJmEcoWgkeEL p0dXX1Jrbv0QKIdfUC8OG5MxOHcxKbZx00URMwBXn31pAiwvnvXrCEllY+2xYzuU/R3lhBwni4Q0a hrU7pOAcrC6UIgJZ8iYw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gjkOt-0004dc-6Z; Wed, 16 Jan 2019 12:34:31 +0000 Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gjkOr-0004dF-9T; Wed, 16 Jan 2019 12:34:29 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id A441B2029D919; Wed, 16 Jan 2019 13:34:27 +0100 (CET) Date: Wed, 16 Jan 2019 13:34:27 +0100 From: Peter Zijlstra To: Matthew Wilcox Subject: Re: [PATCH V2] mm: Introduce GFP_PGTABLE Message-ID: <20190116123427.GE10803@hirez.programming.kicks-ass.net> References: <1547619692-7946-1-git-send-email-anshuman.khandual@arm.com> <20190116065703.GE24149@dhcp22.suse.cz> <20190116123018.GF6310@bombadil.infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190116123018.GF6310@bombadil.infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, christoffer.dall@arm.com, linux-sh@vger.kernel.org, catalin.marinas@arm.com, dave.hansen@linux.intel.com, will.deacon@arm.com, Michal Hocko , linux-mm@kvack.org, linux-riscv@lists.infradead.org, kvmarm@lists.cs.columbia.edu, mpe@ellerman.id.au, greentime@andestech.com, linux@armlinux.org.uk, mingo@redhat.com, vbabka@suse.cz, rientjes@google.com, palmer@sifive.com, Anshuman Khandual , marc.zyngier@arm.com, rppt@linux.vnet.ibm.com, shakeelb@google.com, kirill@shutemov.name, tglx@linutronix.de, linux-arm-kernel@lists.infradead.org, ard.biesheuvel@linaro.org, robin.murphy@arm.com, steve.capper@arm.com, linux-kernel@vger.kernel.org, james.morse@arm.com, aneesh.kumar@linux.ibm.com, akpm@linux-foundation.org, linuxppc-dev@lists.ozlabs.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Jan 16, 2019 at 04:30:18AM -0800, Matthew Wilcox wrote: > On Wed, Jan 16, 2019 at 07:57:03AM +0100, Michal Hocko wrote: > > On Wed 16-01-19 11:51:32, Anshuman Khandual wrote: > > > All architectures have been defining their own PGALLOC_GFP as (GFP_KERNEL | > > > __GFP_ZERO) and using it for allocating page table pages. This causes some > > > code duplication which can be easily avoided. GFP_KERNEL allocated and > > > cleared out pages (__GFP_ZERO) are required for page tables on any given > > > architecture. This creates a new generic GFP flag flag which can be used > > > for any page table page allocation. Does not cause any functional change. > > > > > > GFP_PGTABLE is being added into include/asm-generic/pgtable.h which is the > > > generic page tabe header just to prevent it's potential misuse as a general > > > allocation flag if included in include/linux/gfp.h. > > > > I haven't reviewed the patch yet but I am wondering whether this is > > really worth it without going all the way down to unify the common code > > and remove much more code duplication. Or is this not possible for some > > reason? > > Exactly what I suggested doing in response to v1. > > Also, the approach taken here is crazy. x86 has a feature that no other > architecture has bothered to implement yet -- accounting page tables > to the process. Yet instead of spreading that goodness to all other > architectures, Anshuman has gone to more effort to avoid doing that. Also, s390 (of course, who else) has a fun custom page-table allocator for reasons that don't apply to many other archs. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel