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From: Frederic Weisbecker <frederic@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Frederic Weisbecker <frederic@kernel.org>,
	Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
	Peter Zijlstra <peterz@infradead.org>,
	"David S . Miller" <davem@davemloft.net>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Pavan Kondeti <pkondeti@codeaurora.org>,
	Ingo Molnar <mingo@kernel.org>,
	Joel Fernandes <joel@joelfernandes.org>
Subject: [PATCH 27/37] softirq: Check enabled vectors before processing
Date: Thu, 28 Feb 2019 18:12:32 +0100	[thread overview]
Message-ID: <20190228171242.32144-28-frederic@kernel.org> (raw)
In-Reply-To: <20190228171242.32144-1-frederic@kernel.org>

There is no need to process softirqs if none of those pending are
enabled. Check about that early to avoid unnecessary overhead.

Reviewed-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Pavan Kondeti <pkondeti@codeaurora.org>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
---
 include/linux/interrupt.h |  5 +++++
 kernel/softirq.c          | 21 +++++++++++----------
 2 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 1f4bd62ae218..2bb8b7fcfb15 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -510,6 +510,11 @@ static inline void softirq_pending_set_mask(unsigned int pending)
 }
 #endif /* local_softirq_data */
 
+static inline int softirq_pending_enabled(void)
+{
+	return local_softirq_pending() & local_softirq_enabled();
+}
+
 /* map softirq index to softirq name. update 'softirq_to_name' in
  * kernel/softirq.c when adding a new softirq.
  */
diff --git a/kernel/softirq.c b/kernel/softirq.c
index e957615102dc..6c703bbb718b 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -183,7 +183,7 @@ void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
 	 */
 	preempt_count_sub(cnt - 1);
 
-	if (unlikely(!in_interrupt() && local_softirq_pending())) {
+	if (unlikely(!in_interrupt() && softirq_pending_enabled())) {
 		/*
 		 * 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.
@@ -252,7 +252,7 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
 	int max_restart = MAX_SOFTIRQ_RESTART;
 	struct softirq_action *h;
 	bool in_hardirq;
-	__u32 pending;
+	__u32 pending, enabled;
 	int softirq_bit;
 
 	/*
@@ -262,7 +262,8 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
 	 */
 	current->flags &= ~PF_MEMALLOC;
 
-	pending = local_softirq_pending();
+	enabled = local_softirq_enabled();
+	pending = local_softirq_pending() & enabled;
 	account_irq_enter_time(current);
 
 	__local_bh_disable_ip(_RET_IP_, SOFTIRQ_OFFSET);
@@ -270,7 +271,7 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
 
 restart:
 	/* Reset the pending bitmask before enabling irqs */
-	softirq_pending_clear_mask(SOFTIRQ_ALL_MASK);
+	softirq_pending_clear_mask(pending);
 
 	local_irq_enable();
 
@@ -307,7 +308,7 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
 		rcu_softirq_qs();
 	local_irq_disable();
 
-	pending = local_softirq_pending();
+	pending = local_softirq_pending() & enabled;
 	if (pending) {
 		if (time_before(jiffies, end) && !need_resched() &&
 		    --max_restart)
@@ -333,7 +334,7 @@ asmlinkage __visible void do_softirq(void)
 
 	local_irq_save(flags);
 
-	pending = local_softirq_pending();
+	pending = softirq_pending_enabled();
 
 	if (pending && !ksoftirqd_running(pending))
 		do_softirq_own_stack();
@@ -362,7 +363,7 @@ void irq_enter(void)
 
 static inline void invoke_softirq(void)
 {
-	if (ksoftirqd_running(local_softirq_pending()))
+	if (ksoftirqd_running(softirq_pending_enabled()))
 		return;
 
 	if (!force_irqthreads) {
@@ -411,7 +412,7 @@ void irq_exit(void)
 #endif
 	account_irq_exit_time(current);
 	preempt_count_sub(HARDIRQ_OFFSET);
-	if (!in_interrupt() && local_softirq_pending())
+	if (!in_interrupt() && softirq_pending_enabled())
 		invoke_softirq();
 
 	tick_irq_exit();
@@ -642,13 +643,13 @@ void __init softirq_init(void)
 
 static int ksoftirqd_should_run(unsigned int cpu)
 {
-	return local_softirq_pending();
+	return softirq_pending_enabled();
 }
 
 static void run_ksoftirqd(unsigned int cpu)
 {
 	local_irq_disable();
-	if (local_softirq_pending()) {
+	if (softirq_pending_enabled()) {
 		/*
 		 * We can safely run softirq on inline stack, as we are not deep
 		 * in the task stack here.
-- 
2.21.0


  parent reply	other threads:[~2019-02-28 17:14 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-28 17:12 [PATCH 00/37] softirq: Per vector masking v3 Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 01/37] locking/lockdep: Move valid_state() inside CONFIG_TRACE_IRQFLAGS && CONFIG_PROVE_LOCKING Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 02/37] locking/lockdep: Use expanded masks on find_usage_*() functions Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 03/37] locking/lockdep: Introduce struct lock_usage Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 04/37] locking/lockdep: Convert usage_mask to u64 Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 05/37] locking/lockdep: Introduce lock usage mask iterator Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 06/37] locking/lockdep: Test all incompatible scenario at once in check_irq_usage() Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 07/37] locking/lockdep: Prepare valid_state() to handle plain masks Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 08/37] locking/lockdep: Prepare check_usage_*() " Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 09/37] locking/lockdep: Prepare state_verbose() to handle all softirqs Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 10/37] locking/lockdep: Make mark_lock() fastpath to work with multiple usage at once Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 11/37] locking/lockdep: Save stack trace for each softirq vector involved Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 12/37] locking/lockdep: Report all usages on mark_lock() verbosity mode Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 13/37] softirq: Macrofy softirq vectors Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 14/37] locking/lockdep: Define per vector softirq lock usage states Frederic Weisbecker
2019-04-09 12:03   ` Peter Zijlstra
2019-02-28 17:12 ` [PATCH 15/37] softirq: Pass softirq vector number to lockdep on vector execution Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 16/37] x86: Revert "x86/irq: Demote irq_cpustat_t::__softirq_pending to u16" Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 17/37] arch/softirq: Rename softirq_pending fields to softirq_data Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 18/37] softirq: Normalize softirq_pending naming scheme Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 19/37] softirq: Convert softirq_pending_*() to set/clear mask scheme Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 20/37] softirq: Introduce disabled softirq vectors bits Frederic Weisbecker
2019-03-01 11:29   ` Sebastian Andrzej Siewior
2019-02-28 17:12 ` [PATCH 21/37] softirq: Rename _local_bh_enable() to local_bh_enable_no_softirq() Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 22/37] softirq: Move vectors bits to bottom_half.h Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 23/37] x86: Init softirq enabled field Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 24/37] parisc: " Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 25/37] powerpc: " Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 26/37] softirq: Init softirq enabled field for default irq_stat definition Frederic Weisbecker
2019-02-28 17:12 ` Frederic Weisbecker [this message]
2019-02-28 17:12 ` [PATCH 28/37] softirq: Remove stale comment Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 29/37] softirq: Uninline !CONFIG_TRACE_IRQFLAGS __local_bh_disable_ip() Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 30/37] softirq: Prepare for mixing all/per-vector masking Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 31/37] softirq: Support per vector masking Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 32/37] locking/lockdep: Remove redundant softirqs on check Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 33/37] locking/lockdep: Update check_flags() according to new layout Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 34/37] locking/lockdep: Branch the new vec-finegrained softirq masking to lockdep Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 35/37] softirq: Allow to soft interrupt vector-specific masked contexts Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 36/37] locking: Introduce spin_[un]lock_bh_mask() Frederic Weisbecker
2019-02-28 17:12 ` [PATCH 37/37] net: Make softirq vector masking finegrained on release_sock() Frederic Weisbecker
2019-02-28 17:33 ` [PATCH 00/37] softirq: Per vector masking v3 Linus Torvalds
2019-03-01  3:45   ` Frederic Weisbecker
2019-03-01 16:51     ` Linus Torvalds
2019-03-08 15:30       ` Frederic Weisbecker

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