Use tif_need_resched(NR_now) instead of need_resched() to be explicit
that this path only reschedules if it is needed imminently.
Also, add a comment about why we need a need-resched check here at
all, given that the top level conditional already has checked the
preempt_count().
Cc: Peter Zijlstra <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Originally-by: Thomas Gleixner <[email protected]>
Link: https://lore.kernel.org/lkml/87jzshhexi.ffs@tglx/
Signed-off-by: Ankur Arora <[email protected]>
---
kernel/entry/common.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index 5c5befb05410..e1e6d7c92ca2 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -301,7 +301,15 @@ void raw_irqentry_exit_cond_resched(void)
rcu_irq_exit_check_preempt();
if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
WARN_ON_ONCE(!on_thread_stack());
- if (need_resched())
+
+ /*
+ * Check if we need to preempt eagerly.
+ *
+ * Note we need an explicit check here because some archs don't
+ * fold TIF_NEED_RESCHED in the preempt_count. For archs that
+ * do, this is already covered in the conditinal above.
+ */
+ if (tif_need_resched(NR_now))
preempt_schedule_irq();
}
}
--
2.31.1