Patching until the COWs come home (part 1)

Posted Mar 23, 2021 10:08 UTC (Tue) by pbonzini (subscriber, #60935)
In reply to: Patching until the COWs come home (part 1) by NYKevin
Parent article: Patching until the COWs come home (part 1)

posix_spawn() is not a single system call (technically both fork() and vfork() are wrappers around clone(2), but at least the latter is a single system call).

Patching until the COWs come home (part 1)

Posted Mar 23, 2021 16:12 UTC (Tue) by NYKevin (subscriber, #129325) [Link] (2 responses)

Well sure, but in the (absurd) hypothetical where we're eliminating COW, the kernel would presumably need to grow an interface with capabilities similar to fork+exec, and the POSIX standard name for that interface is posix_spawn.

Patching until the COWs come home (part 1)

Posted Mar 23, 2021 23:00 UTC (Tue) by Cyberax (✭ supporter ✭, #52523) [Link] (1 responses)

Apparently, people dislike posix_spawn. Perhaps we would grow a full replacement that would allow to create a suspended process, tweak its attributes (using file handle-based API) and then resume it.

But I feel what we might actually get is a io_uring-based API that does this using BPF.

Patching until the COWs come home (part 1)

Posted Mar 24, 2021 1:45 UTC (Wed) by foom (subscriber, #14868) [Link]

We _almost_ have that api already: ptrace.

Minor problem being that ptrace is really awful. It's too bad the proposals to add a saner handle based version have all died off.