diff options
| author | Tejun Heo <tj@kernel.org> | 2024-11-09 10:43:55 -1000 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2024-11-09 10:43:55 -1000 |
| commit | a6250aa251eacaf3ebfcfe152a96a727fd483ecd (patch) | |
| tree | 763a6d78a04ea2d66f8baa2406d7c704094f7f6f /kernel/sched/sched.h | |
| parent | a759bf0dfc4db3cb6556fc79c7c98da3a46b2b80 (diff) | |
sched_ext: Handle cases where pick_task_scx() is called without preceding balance_scx()
sched_ext dispatches tasks from the BPF scheduler from balance_scx() and
thus every pick_task_scx() call must be preceded by balance_scx(). While
this usually holds, due to a bug, there are cases where the fair class's
balance() returns true indicating that it has tasks to run on the CPU and
thus terminating balance() calls but fails to actually find the next task to
run when pick_task() is called. In such cases, pick_task_scx() can be called
without preceding balance_scx().
Detect this condition using SCX_RQ_BAL_PENDING flags. If detected, keep
running the previous task if possible and avoid stalling from entering idle
without balancing.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/Ztj_h5c2LYsdXYbA@slm.duckdns.org
Diffstat (limited to 'kernel/sched/sched.h')
| -rw-r--r-- | kernel/sched/sched.h | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 6085ef50febf..4d79804631e4 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -751,8 +751,9 @@ enum scx_rq_flags { */ SCX_RQ_ONLINE = 1 << 0, SCX_RQ_CAN_STOP_TICK = 1 << 1, - SCX_RQ_BAL_KEEP = 1 << 2, /* balance decided to keep current */ - SCX_RQ_BYPASSING = 1 << 3, + SCX_RQ_BAL_PENDING = 1 << 2, /* balance hasn't run yet */ + SCX_RQ_BAL_KEEP = 1 << 3, /* balance decided to keep current */ + SCX_RQ_BYPASSING = 1 << 4, SCX_RQ_IN_WAKEUP = 1 << 16, SCX_RQ_IN_BALANCE = 1 << 17, |