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> Basically I still believe that to do application-side paging now that disks are also faster (ratio compared to RAM) is an interesting approach. I still think

> Basically I still believe that to do application-side paging now that disks are also faster (ratio compared to RAM) is an interesting approach. I still think that using the kernel VM to do so is a bad idea in general, but could work for certain apps. Please elaborate. If disk/block-device performance is improving, wouldn't the VM benefit as well? Also the last sentence seems to make more sense the other way around: VM in the general case, user-land memory management for "certain apps".

antirez 10y ago
The OS VM would benefit, the problem is with using the OS VM in order to implement paging in certain applications like Redis. Does not work well because there is a tension between flexibility of in-memory representation and data locality, and OS VM needs data locality because it has no info about content and requires logically grouped data to be in near pages. About VM in the general case: yes if for general case you mean, a random process is running and is out of memory. If we are talking about in-memory systems wanting to off-load data to disk IMHO the default is that VM does not work well.