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From: Frederic Weisbecker <fweisbec@gmail.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@au1.ibm.com>,
	Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	James Hogan <james.hogan@imgtec.com>,
	"James E.J. Bottomley" <jejb@parisc-linux.org>,
	Helge Deller <deller@gmx.de>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	"David S. Miller" <davem@davemloft.net>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH 3/3] irq: Comment on the use of inline stack for ksoftirq
Date: Thu,  5 Sep 2013 17:33:24 +0200	[thread overview]
Message-ID: <1378395204-25342-4-git-send-email-fweisbec@gmail.com> (raw)
In-Reply-To: <1378395204-25342-1-git-send-email-fweisbec@gmail.com>

Ksoftirqd shouldn't need softirq stack since it's executing
in a kernel thread with a callstack that is only beginning at
this stage.

Lets comment about that for clarity.

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>
---
 kernel/softirq.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/kernel/softirq.c b/kernel/softirq.c
index 657e047..1de0322 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -759,6 +759,7 @@ static void run_ksoftirqd(unsigned int cpu)
 {
 	local_irq_disable();
 	if (local_softirq_pending()) {
+		/* No need to use softirq stack here */
 		__do_softirq();
 		rcu_note_context_switch(cpu);
 		local_irq_enable();
-- 
1.7.5.4


  parent reply	other threads:[~2013-09-05 15:33 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-04 21:39 do_softirq() vs __do_softirq() in irq_exit() and stack overflow Benjamin Herrenschmidt
2013-09-05  0:27 ` Benjamin Herrenschmidt
2013-09-05 13:29 ` Frederic Weisbecker
2013-09-05 15:33 ` [RFC PATCH 0/3] irq: Fix stack overflow due to softirq called on current stack Frederic Weisbecker
2013-09-05 15:33   ` [PATCH 1/3] irq: Consolidate do_softirq() arch overriden implementations Frederic Weisbecker
2013-09-05 15:33   ` [PATCH 2/3] irq: Execute softirq on its own stack on irq exit Frederic Weisbecker
2013-09-05 15:33   ` Frederic Weisbecker [this message]
2013-09-05 22:56     ` [PATCH 3/3] irq: Comment on the use of inline stack for ksoftirq Frederic Weisbecker
2013-09-05 22:18   ` [RFC PATCH 0/3] irq: Fix stack overflow due to softirq called on current stack Benjamin Herrenschmidt
2013-09-18  6:51   ` Paul Mackerras
2013-09-19 15:38     ` Frederic Weisbecker

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