On Mon 20-11-17 20:48:10, Shawn Landden wrote: > On Mon, Nov 20, 2017 at 12:35 AM, Michal Hocko <mhocko@xxxxxxxxxx> wrote: > > On Fri 17-11-17 20:45:03, Shawn Landden wrote: > >> On Fri, Nov 3, 2017 at 2:09 AM, Michal Hocko <mhocko@xxxxxxxxxx> wrote: > >> > >> > On Thu 02-11-17 23:35:44, Shawn Landden wrote: > >> > > It is common for services to be stateless around their main event loop. > >> > > If a process sets PR_SET_IDLE to PR_IDLE_MODE_KILLME then it > >> > > signals to the kernel that epoll_wait() and friends may not complete, > >> > > and the kernel may send SIGKILL if resources get tight. > >> > > > >> > > See my systemd patch: https://github.com/shawnl/systemd/tree/prctl > >> > > > >> > > Android uses this memory model for all programs, and having it in the > >> > > kernel will enable integration with the page cache (not in this > >> > > series). > >> > > > >> > > 16 bytes per process is kinda spendy, but I want to keep > >> > > lru behavior, which mem_score_adj does not allow. When a supervisor, > >> > > like Android's user input is keeping track this can be done in > >> > user-space. > >> > > It could be pulled out of task_struct if an cross-indexing additional > >> > > red-black tree is added to support pid-based lookup. > >> > > >> > This is still an abuse and the patch is wrong. We really do have an API > >> > to use I fail to see why you do not use it. > >> > > >> When I looked at wait_queue_head_t it was 20 byes. > > > > I do not understand. What I meant to say is that we do have a proper > > user api to hint OOM killer decisions. > This is a FIFO queue, rather than a heuristic, which is all you get > with the current API. Yes I can read the code. All I am saing is that we already have an API to achieve what you want or at least very similar. Let me be explicit. Nacked-by: Michal Hocko <mhocko@xxxxxxxx> until it is sufficiently explained that the oom_score_adj is not suitable and there are no other means to achieve what you need. -- Michal Hocko SUSE Labs
