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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2013-09-05 16:14:00 +0200 |
|---|---|---|
| committer | Frederic Weisbecker <fweisbec@gmail.com> | 2013-10-01 12:53:27 +0200 |
| commit | 0bed698a334766ed07bacd6cb33f0228003a7f61 (patch) | |
| tree | 476b852529e75b8d9d3c6e8bedd21468cb1e8f82 /kernel/softirq.c | |
| parent | irq: Improve a bit softirq debugging (diff) | |
| download | linux-0bed698a334766ed07bacd6cb33f0228003a7f61.tar.xz linux-0bed698a334766ed07bacd6cb33f0228003a7f61.zip | |
irq: Justify the various softirq stack choices
For clarity, comment the various stack choices for softirqs
processing, whether we execute them from ksoftirqd or
local_irq_enable() calls.
Their use on irq_exit() is already commented.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@au1.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Mackerras <paulus@au1.ibm.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: James E.J. Bottomley <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'kernel/softirq.c')
| -rw-r--r-- | kernel/softirq.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/kernel/softirq.c b/kernel/softirq.c index 9f8092b82a94..2b4328ea769f 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -170,8 +170,13 @@ static inline void _local_bh_enable_ip(unsigned long ip) */ sub_preempt_count(SOFTIRQ_DISABLE_OFFSET - 1); - if (unlikely(!in_interrupt() && local_softirq_pending())) + if (unlikely(!in_interrupt() && local_softirq_pending())) { + /* + * Run softirq if any pending. And do it in its own stack + * as we may be calling this deep in a task call stack already. + */ do_softirq(); + } dec_preempt_count(); #ifdef CONFIG_TRACE_IRQFLAGS @@ -769,6 +774,10 @@ static void run_ksoftirqd(unsigned int cpu) { local_irq_disable(); if (local_softirq_pending()) { + /* + * We can safely run softirq on inline stack, as we are not deep + * in the task stack here. + */ __do_softirq(); rcu_note_context_switch(cpu); local_irq_enable(); |