On Fri, 13 Nov 2020 09:34:48 -0800 Suren Baghdasaryan <surenb@xxxxxxxxxx> wrote: > When a process is being killed it might be in an uninterruptible sleep > which leads to an unpredictable delay in its memory reclaim. In low memory > situations, when it's important to free up memory quickly, such delay is > problematic. Kernel solves this problem with oom-reaper thread which > performs memory reclaim even when the victim process is not runnable. > Userspace currently lacks such mechanisms and the need and potential > solutions were discussed before (see links below). > This patch provides a mechanism to perform memory reclaim in the context > of the process that sends SIGKILL signal. New SYNC_REAP_MM flag for > pidfd_send_signal syscall can be used only when sending SIGKILL signal > and will lead to the caller synchronously reclaiming the memory that > belongs to the victim and can be easily reclaimed. hm. Seems to me that the ability to reap another process's memory is a generally useful one, and that it should not be tied to delivering a signal in this fashion. And we do have the new process_madvise(MADV_PAGEOUT). It may need a few changes and tweaks, but can't that be used to solve this problem?
