> > > This is a multi-stage process, first we save and replace page table > > > entry with special HMM entry, also flushing tlb in the process. If > > > we run into non allocated entry we either use the zero page or we > > > allocate new page. For swaped entry we try to swap them in. > > > > > Please elaborate why swap entry is handled this way. > > So first, this is only when you have a device then use HMM and a device > that use memory migration. So far it only make sense for discrete GPUs. > So regular workload that do not use a GPUs with HMM are not impacted and > will not go throught this code path. > > Now, here we are migrating memory because the device driver is asking for > it, so presumably we are expecting that the device will use that memory > hence we want to swap in anything that have been swap to disk. Once it is > swap in memory we copy it to device memory and free the pages. So in the > end we only need to allocate a page temporarily until we move things to > the device. > I prefer it is in log message. thanks Hillf -- 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>