scx_nest: Set timer callback after cancelling #92
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In scx_nest, we use a per-cpu BPF timer to schedule compaction for a primary core before it goes idle. If a task comes along that could use that core, we cancel the callback with bpf_timer_cancel(). bpf_timer_cancel() drops a refcnt on the prog and nullifies the callback, so if we want to schedule the callback again, we must use bpf_timer_set_callback() to reset the prog. This patch does that. Reported-by: Julia Lawall <julia.lawall@inria.fr> Signed-off-by: David Vernet <void@manifault.com>
Now that scheduling BPF timers works correctly, we don't need this extra logic to eagerly compact if a scheduling for compaction has happened a few times in a row. Let's remove it. Signed-off-by: David Vernet <void@manifault.com>
htejun
approved these changes
Jan 17, 2024
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scx_nest: Set timer callback after cancelling
In scx_nest, we use a per-cpu BPF timer to schedule compaction for a
primary core before it goes idle. If a task comes along that could use
that core, we cancel the callback with bpf_timer_cancel().
bpf_timer_cancel() drops a refcnt on the prog and nullifies the
callback, so if we want to schedule the callback again, we must use
bpf_timer_set_callback() to reset the prog. This patch does that.
Reported-by: Julia Lawall julia.lawall@inria.fr
Signed-off-by: David Vernet void@manifault.com