Re: [PATCH] Force processes to non-realtime before mm_exit
From: Corey Minyard <hidden>
Date: 2016-06-05 00:28:15
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lkml
On 06/03/2016 06:18 PM, Brian Silverman wrote:
Without this, a realtime process which has called mlockall exiting causes large latencies for other realtime processes at the same or lower priorities. This seems like a fairly common use case too, because realtime processes generally want their memory locked into RAM.
Could this cause a subtle priority inversion for a process waiting on this process to die? I'm thinking that if this is a critical process, it crashes, and the system is very busy with other RT processes, it could take a long time before the process gets restarted when it is expected to happen quickly. I don't have another solution for you, and beyond speeding up the memory reclamation process (which may not be possible or easy) I'm not sure there is. I'm just pointing out a possible side effect. -corey
quoted hunk ↗ jump to hunk
Signed-off-by: Brian Silverman <redacted> --- kernel/exit.c | 6 ++++++ 1 file changed, 6 insertions(+)diff --git a/kernel/exit.c b/kernel/exit.c index a0cf72b..68a97df 100644 --- a/kernel/exit.c +++ b/kernel/exit.c@@ -730,6 +730,12 @@ void do_exit(long code) tsk->exit_code = code; taskstats_exit(tsk, group_dead); + if (tsk->policy == SCHED_FIFO || tsk->policy == SCHED_RR) { + struct sched_param param = { .sched_priority = 0 }; + + sched_setscheduler_nocheck(current, SCHED_NORMAL, ¶m); + } + exit_mm(tsk); if (group_dead)