On Tue, Nov 03, 2020 at 01:40:41PM -0800, Suren Baghdasaryan wrote: > On Tue, Nov 3, 2020 at 1:32 PM Minchan Kim <minchan@xxxxxxxxxx> wrote: > > > > On Tue, Nov 03, 2020 at 10:35:50AM +0100, Michal Hocko wrote: > > > On Mon 02-11-20 12:29:24, Suren Baghdasaryan wrote: > > > [...] > > > > To follow up on this. Should I post an RFC implementing SIGKILL_SYNC > > > > which in addition to sending a kill signal would also reap the > > > > victim's mm in the context of the caller? Maybe having some code will > > > > get the discussion moving forward? > > > > > > Yeah, having a code, even preliminary, might help here. This definitely > > > needs a good to go from process management people as that proper is land > > > full of surprises... > > > > Just to remind a idea I suggested to reuse existing concept > > > > fd = pidfd_open(victim process) > > fdatasync(fd); > > close(fd); > > > > Yep, I just posted a comment about that. I think though your above > sequence is missing a pidfd_send_signal(fd, SIGKILL) before the > fdatasync(fd)... > Not sure if fdatasync(pidfd) or fsync(pidfd) would be more appropriate > for this but will use one and we can discuss details in the RFC with > the code. IMO, fdatasync would be better symantic since fsync invovles metadata (i.e., task_struct, mm_struct and so on). I think what you need is just pages attached to address_space, which sounds like data, not metadata.
