Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [RFC PATCH 4/4] irq: Call tick_irq_enter() inside HARDIRQ_OFFSET | Date | Wed, 25 Nov 2020 03:15:42 +0100 |
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Now that account_irq_enter_time() is called after HARDIRQ_OFFSET has been incremented, there is nothing left that prevents us from also moving tick_irq_enter() after HARDIRQ_OFFSET is incremented.
The desired outcome is to remove the nasty hack that prevents softirqs from being raised through ksoftirqd instead of the hardirq bottom half. Also tick_irq_enter() then becomes appropriately covered by lockdep.
Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> --- kernel/softirq.c | 14 +++++--------- 1 file changed, 5 insertions(+), 9 deletions(-)
diff --git a/kernel/softirq.c b/kernel/softirq.c index 24254c41bb7c..447ee4d6fe4d 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -377,16 +377,12 @@ asmlinkage __visible void __softirq_entry __do_softirq(void) */ void irq_enter_rcu(void) { - if (is_idle_task(current) && !in_interrupt()) { - /* - * Prevent raise_softirq from needlessly waking up ksoftirqd - * here, as softirq will be serviced on return from interrupt. - */ - local_bh_disable(); + __irq_enter_raw(); + + if (is_idle_task(current) && (irq_count() == HARDIRQ_OFFSET)) tick_irq_enter(); - _local_bh_enable(); - } - __irq_enter(); + + account_irq_enter_time(current); } /** -- 2.25.1
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