On 18.01.25 16:31, Dust Li wrote: > On 2025-01-17 11:38:39, Niklas Schnelle wrote: >> On Fri, 2025-01-17 at 10:13 +0800, Dust Li wrote: >>>> >> ---8<--- >>>> Here are some of my thoughts on the matter: >>>>>> >>>>>> Naming and Structure: I suggest we refer to it as SHD (Shared Memory >>>>>> Device) instead of ISM (Internal Shared Memory). >>>> >>>> >>>> So where does the 'H' come from? If you want to call it Shared Memory _D_evice? >>> >>> Oh, I was trying to refer to SHM(Share memory file in the userspace, see man >>> shm_open(3)). SMD is also OK. >>> >>>> >>>> >>>> To my knowledge, a >>>>>> "Shared Memory Device" better encapsulates the functionality we're >>>>>> aiming to implement. >>>> >>>> >>>> Could you explain why that would be better? >>>> 'Internal Shared Memory' is supposed to be a bit of a counterpart to the >>>> Remote 'R' in RoCE. Not the greatest name, but it is used already by our ISM >>>> devices and by ism_loopback. So what is the benefit in changing it? >>> >>> 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. >>> >>> In my opinion, "ISM" doesn’t quite capture what the device provides. >>> Since we’re adding a "Device" that enables different entities (such 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’m 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. > > Make sense, I agree with MCD. > > Best regard, > Dust > In the discussion with Andrew Lunn, it showed that a) we need an abstract description of 'ISM' devices (noted) b) DMBs (Direct Memory Buffers) are a critical differentiator. So what do your think of Direct Memory Communication (DMC) as class name for these devices? I don't have a strong preference (we could also stay with ISM). But DMC may be a bit more concrete than MCD or ISM.
