On 25/10/16 04:38, Dave Hansen wrote: > On 10/23/2016 09:31 PM, Anshuman Khandual wrote: >> VMAs containing coherent device memory should be marked with VM_CDM. These >> VMAs need to be identified in various core kernel paths and this new flag >> will help in this regard. > > ... and it's sticky? So if a VMA *ever* has one of these funky pages in > it, it's stuck being VM_CDM forever? Never to be merged with other > VMAs? Never to see the light of autonuma ever again? > > What if a 100TB VMA has one page of fancy pants device memory, and the > rest normal vanilla memory? Do we really want to consider the whole > thing fancy? >
Those are good review comments to improve the patchset. > This whole patch set is looking really hackish. If you want things to > be isolated from the VM, them it should probably *actually* be isolated > from the VM. As Jerome mentioned, ZONE_DEVICE is probably a better > thing to use here than to try what you're attempting. > The RFC explains the motivation, this is not fancy pants, it is regular memory from the systems perspective, with some changes as described Thanks for the review! Balbir Singh
