On 01/31/2017 12:55 PM, John Hubbard wrote: > On 01/30/2017 05:57 PM, Dave Hansen wrote: >> On 01/30/2017 05:36 PM, Anshuman Khandual wrote: >>>> Let's say we had a CDM node with 100x more RAM than the rest of the >>>> system and it was just as fast as the rest of the RAM. Would we still >>>> want it isolated like this? Or would we want a different policy? >>> >>> But then the other argument being, dont we want to keep this 100X more >>> memory isolated for some special purpose to be utilized by specific >>> applications ? >> >> I was thinking that in this case, we wouldn't even want to bother with >> having "system RAM" in the fallback lists. A device who got its memory >> usage off by 1% could start to starve the rest of the system. A sane >> policy in this case might be to isolate the "system RAM" from the >> device's. > > I also don't like having these policies hard-coded, and your 100x > example above helps clarify what can go wrong about it. It would be > nicer if, instead, we could better express the "distance" between nodes > (bandwidth, latency, relative to sysmem, perhaps), and let the NUMA > system figure out the Right Thing To Do. > > I realize that this is not quite possible with NUMA just yet, but I > wonder if that's a reasonable direction to go with this? That is complete overhaul of the NUMA representation in the kernel. What CDM attempts is to find a solution with existing NUMA framework and with as little code change as possible. -- 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>
