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[134.134.136.126]) by mx.google.com with ESMTPS id k3si763113pjt.87.2019.06.20.14.31.49 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 20 Jun 2019 14:31:49 -0700 (PDT) Received-SPF: fail (google.com: domain of andi@firstfloor.org does not designate 134.134.136.126 as permitted sender) client-ip=134.134.136.126; Authentication-Results: mx.google.com; spf=fail (google.com: domain of andi@firstfloor.org does not designate 134.134.136.126 as permitted sender) smtp.mailfrom=andi@firstfloor.org X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Jun 2019 14:31:48 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,398,1557212400"; d="scan'208";a="181950299" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.7.201.137]) by fmsmga001.fm.intel.com with ESMTP; 20 Jun 2019 14:31:48 -0700 Received: by tassilo.localdomain (Postfix, from userid 1000) id 8001B300FFA; Thu, 20 Jun 2019 14:31:48 -0700 (PDT) From: Andi Kleen To: Dan Williams Cc: Bjorn Helgaas , Nadav Amit , Andrew Morton , LKML , Linux-MM , Borislav Petkov , Toshi Kani , Peter Zijlstra , Dave Hansen , Ingo Molnar , "Kleen\, Andi" Subject: Re: [PATCH 3/3] resource: Introduce resource cache References: <20190613045903.4922-1-namit@vmware.com> <20190613045903.4922-4-namit@vmware.com> <20190617215750.8e46ae846c09cd5c1f22fdf9@linux-foundation.org> <98464609-8F5A-47B9-A64E-2F67809737AD@vmware.com> <8072D878-BBF2-47E4-B4C9-190F379F6221@vmware.com> Date: Thu, 20 Jun 2019 14:31:48 -0700 In-Reply-To: (Dan Williams's message of "Wed, 19 Jun 2019 14:53:54 -0700") Message-ID: <8736k49c57.fsf@firstfloor.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain 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: Dan Williams writes: > > The underlying issue is that the x86-PAT implementation wants to > ensure that conflicting mappings are not set up for the same physical > address. This is mentioned in the developer manuals as problematic on > some cpus. Andi, is lookup_memtype() and track_pfn_insert() still > relevant? There have been discussions about it in the past, and the right answer will likely differ for different CPUs: But so far the official answer for Intel CPUs is that these caching conflicts should be avoided. So I guess the cache in the original email makes sense for now. -Andi