Messages in this thread | | | Date | Fri, 13 Nov 2020 15:55:39 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 1/1] RFC: add pidfd_send_signal flag to reclaim mm while killing a process |
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On Fri, 13 Nov 2020 09:34:48 -0800 Suren Baghdasaryan <surenb@google.com> 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?
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