"User-space data may not be resident in RAM"
"User-space data may not be resident in RAM"
Posted Jul 8, 2020 12:32 UTC (Wed) by k3ninho (subscriber, #50375)In reply to: "User-space data may not be resident in RAM" by epa
Parent article: Sleepable BPF programs
>...how much kernel could could be simplified out once you know that all user-space data is always in physical RAM?
You're still going to LRU files listed in the VFS cache, and maybe that would go away when you've got enough spare RAM to pin a mount point into the cache -- operating (eg root and home partitions) from RAM at the cost of being write heavy keeping disk in fsync().
You're still going to LRU files listed in the VFS cache, and maybe that would go away when you've got enough spare RAM to pin a mount point into the cache -- operating (eg root and home partitions) from RAM at the cost of being write heavy keeping disk in fsync().
K3n.
Posted Jul 8, 2020 12:54 UTC (Wed)
by epa (subscriber, #39769)
[Link]
"User-space data may not be resident in RAM"
Unless I've misunderstood, the VFS cache is not user-space data. I meant if you can assume that all of a user process's address space (apart from memory-mapped files) is in RAM and so there is no possibility of having to wait for it to be paged in.