On Thu, 20 Apr 2017, Balbir Singh wrote: > Couple of things are needed > > 1. Isolation of allocation cgroups, memory policy and cpuset provide that > 2. Isolation of certain algorithms like kswapd/auto-numa balancing Ok that may mean adding some generic functionality to limit those > > The approach sounds pretty invasive to me. > > Could you please elaborate, you mean the user space programming bits? No I mean the modification of the memory policies in particular. We are adding more exceptions to an already complex and fragile system. Can we do this in a generic way just using hotplug nodes and some of the existing isolation mechanisms? > Ideally we need the following: > > 1. Transparency about being able to allocate memory anywhere and the ability > to migrate memory between coherent device memory and normal system memory If it is a memory node then you have that already. > 2. The ability to explictly allocate memory from coherent device memory Ditto > 3. Isolation of normal allocations from coherent device memory unless > explictly stated, same as (2) above memory policies etc do that. > 4. The ability to hotplug in and out the memory at run-time hotplug code does that. > 5. Exchange pointers between coherent device memory and normal memory > for the compute on the coherent device memory to use I dont see anything preventing that from occurring right now. Thats a device issue with doing proper virtual to physical mapping right? > I could list further things, but largely coherent device memory is like > system memory except that we believe that things like auto-numa balancing > and kswapd will not work well due to lack of information about references > and faults. Ok so far I do not see that we need coherent nodes at all. > Some of the mm-summit notes are at https://lwn.net/Articles/717601/ > The goals align with HMM, except that the device memory is coherent. HMM > has a CDM variation as well. I was at the presentation but at that point you were interested in a different approach it seems. > We've been using the term coherent device memory (CDM). I could rephrase the > text and documentation for consistency. Would you prefer a different term? Hotplug memory node? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
