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,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable 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 D4633C43387 for ; Wed, 16 Jan 2019 12:45:08 +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 856A420657 for ; Wed, 16 Jan 2019 12:45:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="GxRivlC9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 856A420657 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-riscv-bounces+infradead-linux-riscv=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=rajAagzgYCERFVBPTuhc7v3/fSluwh8rmqoJkf5T3sk=; b=GxRivlC9Ebld2G 9yF/tRrWCzJEzRh6ZePp1uhZeSGxm2FxO01QYN8KWqXfKtptdl+glaYKpTQCpfQOpESPHn3KNSPuo i4wj0evVR0tN6bpjHfd048jW6zbXAbDgLyHbhp9mGnGss4f6TuQd0xGBpXMijRh7B/9LPnYpxAvZS 3tLvkS/obPXjUEXVnHydQK0rCYHvxzyMKOJPrc+SwTi6UrtI4CZ5ZeZQ/mk+YQhRx0El+mixvosnR FagzdnpTVv8vTR54IuUomeztJouNLcQljurA/kSvWkZpfN2A+bYNshaZUVPv0Aefd5YZyXENfXD31 fjsaozw7zd3BvFK5qUrw==; 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 1gjkZ7-0002PD-Tp; Wed, 16 Jan 2019 12:45:05 +0000 Received: from mx2.suse.de ([195.135.220.15] helo=mx1.suse.de) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1gjkYj-0001sE-12; Wed, 16 Jan 2019 12:44:46 +0000 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 C0897AED6; Wed, 16 Jan 2019 12:44:37 +0000 (UTC) Date: Wed, 16 Jan 2019 13:44:31 +0100 From: Michal Hocko To: Matthew Wilcox Subject: Re: [PATCH V2] mm: Introduce GFP_PGTABLE Message-ID: <20190116124431.GK24149@dhcp22.suse.cz> 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-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190116_044441_599917_2AA2000D X-CRM114-Status: GOOD ( 16.94 ) X-BeenThere: linux-riscv@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, linux-sh@vger.kernel.org, peterz@infradead.org, catalin.marinas@arm.com, dave.hansen@linux.intel.com, will.deacon@arm.com, christoffer.dall@arm.com, 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-riscv" Errors-To: linux-riscv-bounces+infradead-linux-riscv=archiver.kernel.org@lists.infradead.org On Wed 16-01-19 04:30:18, 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. Yes, I believe the only reason this is x86 only is that each arch would have to be tweaked separately. So a cleanup in _that_ regard would be helpful. There is no real reason to have ptes accounted only for x86. There might be some exceptions but well, our asm-generic allows to opt in for generic implementation or override it with a special one. The later should be an exception rather than the rule. -- Michal Hocko SUSE Labs _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv