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Wythe" , Tony Lu , Wen Gu , Peter Oberparleiter , David Miller , Jakub Kicinski , Paolo Abeni , Eric Dumazet , Andrew Lunn Cc: Thorsten Winkler , netdev@vger.kernel.org, linux-s390@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Simon Horman Date: Fri, 17 Jan 2025 11:38:39 +0100 In-Reply-To: <20250117021353.GF89233@linux.alibaba.com> References: <20250115195527.2094320-1-wintera@linux.ibm.com> <20250116093231.GD89233@linux.alibaba.com> <0f96574a-567e-495a-b815-6aef336f12e6@linux.ibm.com> <20250117021353.GF89233@linux.alibaba.com> Autocrypt: addr=schnelle@linux.ibm.com; prefer-encrypt=mutual; keydata=mQINBGHm3M8BEAC+MIQkfoPIAKdjjk84OSQ8erd2OICj98+GdhMQpIjHXn/RJdCZLa58k /ay5x0xIHkWzx1JJOm4Lki7WEzRbYDexQEJP0xUia0U+4Yg7PJL4Dg/W4Ho28dRBROoJjgJSLSHwc 3/1pjpNlSaX/qg3ZM8+/EiSGc7uEPklLYu3gRGxcWV/944HdUyLcnjrZwCn2+gg9ncVJjsimS0ro/ 2wU2RPE4ju6NMBn5Go26sAj1owdYQQv9t0d71CmZS9Bh+2+cLjC7HvyTHKFxVGOznUL+j1a45VrVS XQ+nhTVjvgvXR84z10bOvLiwxJZ/00pwNi7uCdSYnZFLQ4S/JGMs4lhOiCGJhJ/9FR7JVw/1t1G9a UlqVp23AXwzbcoV2fxyE/CsVpHcyOWGDahGLcH7QeitN6cjltf9ymw2spBzpRnfFn80nVxgSYVG1d w75ksBAuQ/3e+oTQk4GAa2ShoNVsvR9GYn7rnsDN5pVILDhdPO3J2PGIXa5ipQnvwb3EHvPXyzakY tK50fBUPKk3XnkRwRYEbbPEB7YT+ccF/HioCryqDPWUivXF8qf6Jw5T1mhwukUV1i+QyJzJxGPh19 /N2/GK7/yS5wrt0Lwxzevc5g+jX8RyjzywOZGHTVu9KIQiG8Pqx33UxZvykjaqTMjo7kaAdGEkrHZ dVHqoPZwhCsgQARAQABtChOaWtsYXMgU2NobmVsbGUgPHNjaG5lbGxlQGxpbnV4LmlibS5jb20+iQ JXBBMBCABBAhsBBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAAhkBFiEEnbAAstJ1IDCl9y3cr+Q/Fej CYJAFAmWVooIFCQWP+TMACgkQr+Q/FejCYJCmLg/+OgZD6wTjooE77/ZHmW6Egb5nUH6DU+2nMHMH UupkE3dKuLcuzI4aEf/6wGG2xF/LigMRrbb1iKRVk/VG/swyLh/OBOTh8cJnhdmURnj3jhaefzslA 1wTHcxeH4wMGJWVRAhOfDUpMMYV2J5XoroiA1+acSuppelmKAK5voVn9/fNtrVr6mgBXT5RUnmW60 UUq5z6a1zTMOe8lofwHLVvyG9zMgv6Z9IQJc/oVnjR9PWYDUX4jqFL3yO6DDt5iIQCN8WKaodlNP6 1lFKAYujV8JY4Ln+IbMIV2h34cGpIJ7f76OYt2XR4RANbOd41+qvlYgpYSvIBDml/fT2vWEjmncm7 zzpVyPtCZlijV3npsTVerGbh0Ts/xC6ERQrB+rkUqN/fx+dGnTT9I7FLUQFBhK2pIuD+U1K+A+Egw UiTyiGtyRMqz12RdWzerRmWFo5Mmi8N1jhZRTs0yAUn3MSCdRHP1Nu3SMk/0oE+pVeni3ysdJ69Sl kCAZoaf1TMRdSlF71oT/fNgSnd90wkCHUK9pUJGRTUxgV9NjafZy7sx1Gz11s4QzJE6JBelClBUiF 6QD4a+MzFh9TkUcpG0cPNsFfEGyxtGzuoeE86sL1tk3yO6ThJSLZyqFFLrZBIJvYK2UiD+6E7VWRW 9y1OmPyyFBPBosOvmrkLlDtAtyfYInO0KU5pa2xhcyBTY2huZWxsZSA8bmlrbGFzLnNjaG5lbGxlQ GlibS5jb20+iQJUBBMBCAA+AhsBBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAFiEEnbAAstJ1IDCl9y 3cr+Q/FejCYJAFAmWVoosFCQWP+TMACgkQr+Q/FejCYJB7oxAAksHYU+myhSZD0YSuYZl3oLDUEFP 3fm9m6N9zgtiOg/GGI0jHc+Tt8qiQaLEtVeP/waWKgQnje/emHJOEDZTb0AdeXZk+T5/ydrKRLmYC 6rPge3ue1yQUCiA+T72O3WfjZILI2yOstNwd1f0epQ32YaAvM+QbKDloJSmKhGWZlvdVUDXWkS6/m aUtUwZpddFY8InXBxsYCbJsqiKF3kPVD515/6keIZmZh1cTIFQ+Kc+UZaz0MxkhiCyWC4cH6HZGKR fiXLhPlmmAyW9FiZK9pwDocTLemfgMR6QXOiB0uisdoFnjhXNfp6OHSy7w7LTIHzCsJoHk+vsyvSp +fxkjCXgFzGRQaJkoX33QZwQj1mxeWl594QUfR4DIZ2KERRNI0OMYjJVEtB5jQjnD/04qcTrSCpJ5 ZPtiQ6Umsb1c9tBRIJnL7gIslo/OXBe/4q5yBCtCZOoD6d683XaMPGhi/F6+fnGvzsi6a9qDBgVvt arI8ybayhXDuS6/StR8qZKCyzZ/1CUofxGVIdgkseDhts0dZ4AYwRVCUFQULeRtyoT4dKfEot7hPE /4wjm9qZf2mDPRvJOqss6jObTNuw1YzGlpe9OvDYtGeEfHgcZqEmHbiMirwfGLaTG2xKDx4g2jd2z Ocf83TCERFKJEhvZxB3tRiUQTd3dZ1TIaisv/o+y0K05pa2xhcyBTY2huZWxsZSA8bmlrbGFzLnNj aG5lbGxlQGdtYWlsLmNvbT6JAlQEEwEIAD4CGwEFCwkIBwIGFQoJCAsCBBYCAwECHgECF4AWIQSds ACy0nUgMKX3Ldyv5D8V6MJgkAUCZZWiiwUJBY/5MwAKCRCv5D8V6MJgkNVuEACo12niyoKhnXLQFt NaqxNZ+8p/MGA7g2XcVJ1bYMPoZ2Wh8zwX0sKX/dLlXVHIAeqelL5hIv6GoTykNqQGUN2Kqf0h/z7 b85o3tHiqMAQV0dAB0y6qdIwdiB69SjpPNK5KKS1+AodLzosdIVKb+LiOyqUFKhLnablni1hiKlqY yDeD4k5hePeQdpFixf1YZclGZLFbKlF/A/0Q13USOHuAMYoA/iSgJQDMSUWkuC0mNxdhfVt/gVJnu Kq+uKUghcHflhK+yodqezlxmmRxg6HrPVqRG4pZ6YNYO7YXuEWy9JiEH7MmFYcjNdgjn+kxx4IoYU O0MJ+DjLpVCV1QP1ZvMy8qQxScyEn7pMpQ0aW6zfJBsvoV3EHCR1emwKYO6rJOfvtu1rElGCTe3sn sScV9Z1oXlvo8pVNH5a2SlnsuEBQe0RXNXNJ4RAls8VraGdNSHi4MxcsYEgAVHVaAdTLfJcXZNCIU cZejkOE+U2talW2n5sMvx+yURAEVsT/50whYcvomt0y81ImvCgUz4xN1axZ3PCjkgyhNiqLe+vzge xq7B2Kx2++hxIBDCKLUTn8JUAtQ1iGBZL9RuDrBy2rR7xbHcU2424iSbP0zmnpav5KUg4F1JVYG12 vDCi5tq5lORCL28rjOQqE0aLHU1M1D2v51kjkmNuc2pgLDFzpvgLQhTmlrbGFzIFNjaG5lbGxlIDx uaWtzQGtlcm5lbC5vcmc+iQJUBBMBCAA+AhsBBQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAFiEEnbAA stJ1IDCl9y3cr+Q/FejCYJAFAmWVoosFCQWP+TMACgkQr+Q/FejCYJAglRAAihbDxiGLOWhJed5cF kOwdTZz6MyYgazbr+2sFrfAhX3hxPFoG4ogY/BzsjkN0cevWpSigb2I8Y1sQD7BFWJ2OjpEpVQd0D sk5VbJBXEWIVDBQ4VMoACLUKgfrb0xiwMRg9C2h6KlwrPBlfgctfvrWWLBq7+oqx73CgxqTcGpfFy tD87R4ovR9W1doZbh7pjsH5Ae9xX5PnQFHruib3y35zC8+tvSgvYWv3Eg/8H4QWlrjLHHy2AfZDVl 9F5t5RfGL8NRsiTdVg9VFYg/GDdck9WPEgdO3L/qoq3Iuk0SZccGl+Nj8vtWYPKNlu2UvgYEbB8cl UoWhg+SjjYQka7/p6tc+CCPZ8JUpkgkAdt7yXt6370wP1gct2VztS6SEGcmAE1qxtGhi5Kuln4ZJ/ UO2yxhPHgoW99OuZw3IRHe0+mNR67JbIpSuFWDFNjZ0nckQcU1taSEUi0euWs7i4MEkm0NsOsVhbs 4D2vMiC6kO/FqWOPmWZeAjyJw/KRUG4PaJAr5zJUx57nhKWgeTniW712n4DwCUh77D/PHY0nqBTG/ B+QQCR/FYGpTFkO4DRVfapT8njDrsWyVpP9o64VNZP42S+DuRGWfUKCMAXsM/wPzRiDEVfnZMcUR9 vwLSHeoV7MiIFC0xIrp5ES9R00t4UFgqtGc36DV71qjR+66Im0= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.54.3 (3.54.3-1.fc41) Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-GUID: DTJhf1yHZ7mngKYbw6j3msxxG0evpR2g X-Proofpoint-ORIG-GUID: 5mUbzYkTwYIEZSN2yWJqZTMjBH-N76z7 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-01-17_04,2025-01-16_01,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 suspectscore=0 priorityscore=1501 malwarescore=0 lowpriorityscore=0 adultscore=0 phishscore=0 impostorscore=0 mlxscore=0 mlxlogscore=753 bulkscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2501170084 On Fri, 2025-01-17 at 10:13 +0800, Dust Li wrote: > >=20 ---8<--- > > Here are some of my thoughts on the matter: > > > >=20 > > > > Naming and Structure: I suggest we refer to it as SHD (Shared Memor= y > > > > Device) instead of ISM (Internal Shared Memory).=20 > >=20 > >=20 > > So where does the 'H' come from? If you want to call it Shared Memory _= D_evice? >=20 > Oh, I was trying to refer to SHM(Share memory file in the userspace, see = man > shm_open(3)). SMD is also OK. >=20 > >=20 > >=20 > > To my knowledge, a > > > > "Shared Memory Device" better encapsulates the functionality we're > > > > aiming to implement.=20 > >=20 > >=20 > > Could you explain why that would be better? > > 'Internal Shared Memory' is supposed to be a bit of a counterpart to th= e > > Remote 'R' in RoCE. Not the greatest name, but it is used already by ou= r ISM > > devices and by ism_loopback. So what is the benefit in changing it? >=20 > I believe that if we are going to separate and refine the code, and add > a common subsystem, we should choose the most appropriate name. >=20 > In my opinion, "ISM" doesn=E2=80=99t quite capture what the device provid= es. > Since we=E2=80=99re adding a "Device" that enables different entities (su= ch as > processes or VMs) to perform shared memory communication, I think a more > fitting name would be better. If you have any alternative suggestions, > I=E2=80=99m open to them. I kept thinking about this a bit and I'd like to propose yet another name for this group of devices: Memory Communication Devices (MCD) One important point I see is that there is a bit of a misnomer in the existing ISM name in that our ISM device does in fact *not* share memory in the common sense of the "shared memory" wording. Instead it copies data between partitions of memory that share a common cache/memory hierarchy while not sharing the memory itself. loopback- ism and a possibly future virtio-ism on the other hand would share memory in the "shared memory" sense. Though I'd very much hope they will retain a copy mode to allow use in partition scenarios. With that background I think the common denominator between them and the main idea behind ISM is that they facilitate communication via memory buffers and very simple and reliable copy/share operations. I think this would also capture our planned use-case of devices (TTYs, block devices, framebuffers + HID etc) provided by a peer on top of such a memory communication device. Thanks, Niklas