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<20181126152015.7464c786@naga> From: David Hildenbrand Openpgp: preference=signencrypt Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwX4EEwECACgFAljj9eoCGwMFCQlmAYAGCwkI BwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEE3eEPcA/4Na5IIP/3T/FIQMxIfNzZshIq687qgG 8UbspuE/YSUDdv7r5szYTK6KPTlqN8NAcSfheywbuYD9A4ZeSBWD3/NAVUdrCaRP2IvFyELj xoMvfJccbq45BxzgEspg/bVahNbyuBpLBVjVWwRtFCUEXkyazksSv8pdTMAs9IucChvFmmq3 jJ2vlaz9lYt/lxN246fIVceckPMiUveimngvXZw21VOAhfQ+/sofXF8JCFv2mFcBDoa7eYob s0FLpmqFaeNRHAlzMWgSsP80qx5nWWEvRLdKWi533N2vC/EyunN3HcBwVrXH4hxRBMco3jvM m8VKLKao9wKj82qSivUnkPIwsAGNPdFoPbgghCQiBjBe6A75Z2xHFrzo7t1jg7nQfIyNC7ez MZBJ59sqA9EDMEJPlLNIeJmqslXPjmMFnE7Mby/+335WJYDulsRybN+W5rLT5aMvhC6x6POK z55fMNKrMASCzBJum2Fwjf/VnuGRYkhKCqqZ8gJ3OvmR50tInDV2jZ1DQgc3i550T5JDpToh dPBxZocIhzg+MBSRDXcJmHOx/7nQm3iQ6iLuwmXsRC6f5FbFefk9EjuTKcLMvBsEx+2DEx0E UnmJ4hVg7u1PQ+2Oy+Lh/opK/BDiqlQ8Pz2jiXv5xkECvr/3Sv59hlOCZMOaiLTTjtOIU7Tq 7ut6OL64oAq+zsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCghCj/CA/lc/LMthqQ773ga uB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseBfDXHA6m4B3mUTWo13nid 0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts6TZ+IrPOwT1hfB4WNC+X 2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiuQmt3yqrmN63V9wzaPhC+ xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKBTccu2AXJXWAE1Xjh6GOC 8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvFFFyAS0Nk1q/7EChPcbRb hJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh2YmnmLRTro6eZ/qYwWkC u8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRkF3TwgucpyPtcpmQtTkWS gDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0LLH63+BrrHasfJzxKXzqg rW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4vq7oFCPsOgwARAQABwsFl BBgBAgAPBQJVy5+RAhsMBQkJZgGAAAoJEE3eEPcA/4NagOsP/jPoIBb/iXVbM+fmSHOjEshl KMwEl/m5iLj3iHnHPVLBUWrXPdS7iQijJA/VLxjnFknhaS60hkUNWexDMxVVP/6lbOrs4bDZ NEWDMktAeqJaFtxackPszlcpRVkAs6Msn9tu8hlvB517pyUgvuD7ZS9gGOMmYwFQDyytpepo YApVV00P0u3AaE0Cj/o71STqGJKZxcVhPaZ+LR+UCBZOyKfEyq+ZN311VpOJZ1IvTExf+S/5 lqnciDtbO3I4Wq0ArLX1gs1q1XlXLaVaA3yVqeC8E7kOchDNinD3hJS4OX0e1gdsx/e6COvy qNg5aL5n0Kl4fcVqM0LdIhsubVs4eiNCa5XMSYpXmVi3HAuFyg9dN+x8thSwI836FoMASwOl C7tHsTjnSGufB+D7F7ZBT61BffNBBIm1KdMxcxqLUVXpBQHHlGkbwI+3Ye+nE6HmZH7IwLwV W+Ajl7oYF+jeKaH4DZFtgLYGLtZ1LDwKPjX7VAsa4Yx7S5+EBAaZGxK510MjIx6SGrZWBrrV TEvdV00F2MnQoeXKzD7O4WFbL55hhyGgfWTHwZ457iN9SgYi1JLPqWkZB0JRXIEtjd4JEQcx +8Umfre0Xt4713VxMygW0PnQt5aSQdMD58jHFxTk092mU+yIHj5LeYgvwSgZN4airXk5yRXl SE+xAvmumFBY Organization: Red Hat GmbH Message-ID: <2d05e5d1-c5b5-8884-e642-89421685052f@redhat.com> Date: Mon, 26 Nov 2018 16:59:14 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 MIME-Version: 1.0 In-Reply-To: <20181126152015.7464c786@naga> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.32]); Mon, 26 Nov 2018 15:59:26 +0000 (UTC) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kate Stewart , Rich Felker , linux-ia64@vger.kernel.org, linux-sh@vger.kernel.org, Peter Zijlstra , Dave Hansen , Heiko Carstens , linux-mm@kvack.org, Michal Hocko , Paul Mackerras , "H. Peter Anvin" , Rashmica Gupta , "K. Y. Srinivasan" , Boris Ostrovsky , Stephen Rothwell , Michael Neuling , Stephen Hemminger , Yoshinori Sato , linux-acpi@vger.kernel.org, Ingo Molnar , xen-devel@lists.xenproject.org, Rob Herring , Len Brown , Pavel Tatashin , linux-s390@vger.kernel.org, "mike.travis@hpe.com" , Haiyang Zhang , =?UTF-8?Q?Jonathan_Neusch=c3=a4fer?= , Nicholas Piggin , Joe Perches , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Mike Rapoport , Borislav Petkov , Andy Lutomirski , Dan Williams , Joonsoo Kim , Oscar Salvador , Juergen Gross , Tony Luck , Mathieu Malaterre , Greg Kroah-Hartman , "Rafael J. Wysocki" , linux-kernel@vger.kernel.org, Fenghua Yu , Mauricio Faria de Oliveira , Thomas Gleixner , Philippe Ombredanne , Martin Schwidefsky , devel@linuxdriverproject.org, Andrew Morton , linuxppc-dev@lists.ozlabs.org, "Kirill A. Shutemov" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 26.11.18 15:20, Michal Suchánek wrote: > On Mon, 26 Nov 2018 14:33:29 +0100 > David Hildenbrand wrote: > >> On 26.11.18 13:30, David Hildenbrand wrote: >>> On 23.11.18 19:06, Michal Suchánek wrote: > >>>> >>>> If we are going to fake the driver information we may as well add the >>>> type attribute and be done with it. >>>> >>>> I think the problem with the patch was more with the semantic than the >>>> attribute itself. >>>> >>>> What is normal, paravirtualized, and standby memory? >>>> >>>> I can understand DIMM device, baloon device, or whatever mechanism for >>>> adding memory you might have. >>>> >>>> I can understand "memory designated as standby by the cluster >>>> administrator". >>>> >>>> However, DIMM vs baloon is orthogonal to standby and should not be >>>> conflated into one property. >>>> >>>> paravirtualized means nothing at all in relationship to memory type and >>>> the desired online policy to me. >>> >>> Right, so with whatever we come up, it should allow to make a decision >>> in user space about >>> - if memory is to be onlined automatically >> >> And I will think about if we really should model standby memory. Maybe >> it is really better to have in user space something like (as Dan noted) > > If it is possible to designate the memory as standby or online in the > s390 admin interface and the kernel does have access to this > information it makes sense to forward it to userspace (as separate > s390-specific property). If not then you need to make some kind of > assumption like below and the user can tune the script according to > their usecase. Also true, standby memory really represents a distinct type of memory block (memory seems to be there but really isn't). Right now I am thinking about something like this (tried to formulate it on a very generic level because we can't predict which mechanism might want to make use of these types in the future). /* * Memory block types allow user space to formulate rules if and how to * online memory blocks. The types are exposed to user space as text * strings in sysfs. While the typical online strategies are described * along with the types, there are use cases where that can differ (e.g. * use MOVABLE zone for more reliable huge page usage, use NORMAL zone * due to zone imbalance or because memory unplug is not intended). * * MEMORY_BLOCK_NONE: * No memory block is to be created (e.g. device memory). Used internally * only. * * MEMORY_BLOCK_REMOVABLE: * This memory block type should be treated as if it can be * removed/unplugged from the system again. E.g. there is a hardware * interface to unplug such memory. This memory block type is usually * onlined to the MOVABLE zone, to e.g. make offlining of it more * reliable. Examples include ACPI and PPC DIMMs. * * MEMORY_BLOCK_UNREMOVABLE: * This memory block type should be treated as if it can not be * removed/unplugged again. E.g. there is no hardware interface to * unplug such memory. This memory block type is usually onlined to * the NORMAL zone, as offlining is not beneficial. Examples include boot * memory on most architectures and memory added via balloon devices. * * MEMORY_BLOCK_STANDBY: * The memory block type should be treated as if it can be * removed/unplugged again, however the actual memory hot(un)plug is * performed by onlining/offlining. In virtual environments, such memory * is usually added during boot and never removed. Onlining memory will * result in memory getting allocated to a VM. This memory type is usually * not onlined automatically but explicitly by the administrator. One * example is standby memory on s390x. */ > >> >> if (isS390x() && type == "dimm") { >> /* don't online, on s390x system DIMMs are standby memory */ >> } > > Thanks > > Michal > -- Thanks, David / dhildenb