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[2001:8b0:10b:1231::1]) by mx.google.com with ESMTPS id b15si14689770wrq.75.2019.04.05.09.42.59 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 05 Apr 2019 09:43:00 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of peterz@infradead.org designates 2001:8b0:10b:1231::1 as permitted sender) client-ip=2001:8b0:10b:1231::1; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=merlin.20170209 header.b=mSyEKQ6J; spf=pass (google.com: best guess record for domain of peterz@infradead.org designates 2001:8b0:10b:1231::1 as permitted sender) smtp.mailfrom=peterz@infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=hZhTCIKAv1SX7OWxy0ZNyMB8ohuTPeMfZbFpPWX134E=; b=mSyEKQ6JZ9GlE5lyhXCQh7u8P JA4MAqkaoxKIVkTuxNwnuhPTfHK8zPdr08TWvJ6JUIugUaxRVglFTjUylYGHaD+x2o8dvgpKcO0qz eUjrz8o+fWFx+CYfeZfmOIJ+aXdSmsXEImKgw+nnm+5NO88EzKR1Ru4oeJlFkZLN6b74Yjnuxk5x/ YNCB9uZwVBdLfAFdwruvtEpxUeVrR2zOvWKfK6R7CDAbFlsptY/4EOBPFQyV+yAFaXGPn7y09TUB3 Jes/EhjyBsBuQNRk23wzulz2u4Q54hhn7TZqlLOQu3QFVhULpEEsbU1aqllppWXWEwrrB31MMmbmP PtLOwsb/A==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hCRuO-0005wn-GU; Fri, 05 Apr 2019 16:41:40 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 984BF29AB6604; Fri, 5 Apr 2019 18:41:37 +0200 (CEST) Date: Fri, 5 Apr 2019 18:41:37 +0200 From: Peter Zijlstra To: Andy Lutomirski Cc: Dave Hansen , Thomas Gleixner , Khalid Aziz , Andy Lutomirski , Juerg Haefliger , Tycho Andersen , jsteckli@amazon.de, Andi Kleen , liran.alon@oracle.com, Kees Cook , Konrad Rzeszutek Wilk , deepa.srinivasan@oracle.com, chris hyser , Tyler Hicks , "Woodhouse, David" , Andrew Cooper , Jon Masters , Boris Ostrovsky , kanth.ghatraju@oracle.com, Joao Martins , Jim Mattson , pradeep.vincent@oracle.com, John Haxby , "Kirill A. Shutemov" , Christoph Hellwig , steven.sistare@oracle.com, Laura Abbott , Aaron Lu , Andrew Morton , alexander.h.duyck@linux.intel.com, Amir Goldstein , Andrey Konovalov , aneesh.kumar@linux.ibm.com, anthony.yznaga@oracle.com, Ard Biesheuvel , Arnd Bergmann , arunks@codeaurora.org, Ben Hutchings , Sebastian Andrzej Siewior , Borislav Petkov , brgl@bgdev.pl, Catalin Marinas , Jonathan Corbet , cpandya@codeaurora.org, Daniel Vetter , Dan Williams , Greg KH , Roman Gushchin , Johannes Weiner , "H. Peter Anvin" , Joonsoo Kim , James Morse , Jann Horn , Juergen Gross , Jiri Kosina , James Morris , Joe Perches , Souptick Joarder , Joerg Roedel , Keith Busch , Konstantin Khlebnikov , Logan Gunthorpe , marco.antonio.780@gmail.com, Mark Rutland , Mel Gorman , Michal Hocko , Michal Hocko , Mike Kravetz , Ingo Molnar , "Michael S. Tsirkin" , Marek Szyprowski , Nicholas Piggin , osalvador@suse.de, "Paul E. McKenney" , pavel.tatashin@microsoft.com, Randy Dunlap , richard.weiyang@gmail.com, Rik van Riel , David Rientjes , Robin Murphy , Steven Rostedt , Mike Rapoport , Sai Praneeth Prakhya , "Serge E. Hallyn" , Steve Capper , thymovanbeers@gmail.com, Vlastimil Babka , Will Deacon , Matthew Wilcox , yaojun8558363@gmail.com, Huang Ying , zhangshaokun@hisilicon.com, iommu@lists.linux-foundation.org, X86 ML , linux-arm-kernel , LKML , Linux-MM , LSM List , Khalid Aziz Subject: Re: [RFC PATCH v9 12/13] xpfo, mm: Defer TLB flushes for non-current CPUs (x86 only) Message-ID: <20190405164137.GF4038@hirez.programming.kicks-ass.net> References: <4495dda4bfc4a06b3312cc4063915b306ecfaecb.1554248002.git.khalid.aziz@oracle.com> <91f1dbce-332e-25d1-15f6-0e9cfc8b797b@oracle.com> <26b00051-b03c-9fce-1446-52f0d6ed52f8@intel.com> <36b999d4-adf6-08a3-2897-d77b9cba20f8@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) 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 Fri, Apr 05, 2019 at 10:27:05AM -0600, Andy Lutomirski wrote: > At the risk of asking stupid questions: we already have a mechanism > for this: highmem. Can we enable highmem on x86_64, maybe with some > heuristics to make it work well? That's what I said; but note that I'm still not convinced fixmap/highmem is actually correct TLB wise.