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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 32/37] locking/lockdep: Remove redundant softirqs on check
Date: Thu, 28 Feb 2019 18:12:37 +0100	[thread overview]
Message-ID: <20190228171242.32144-33-frederic@kernel.org> (raw)
In-Reply-To: <20190228171242.32144-1-frederic@kernel.org>

It makes no more sense to check for redundant softirqs on because
trace_softirqs_on() is no more symmetrical to trace_softirqs_off().

Indeed trace_softirqs_off() is called whenever we know that all softirq
vectors have been disabled. And trace_softirqs_on() is called everytime
we enable at least one vector. So curr->softirqs_enabled may well remain
true throughout subsequent calls.

FIXME: Perhaps we should rename those functions. Another solution would
be to make curr->softirqs_enabled to record the last value of
local_softirqs_enabled() so we could track again redundant calls.

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>
---
 kernel/locking/lockdep.c           | 5 -----
 kernel/locking/lockdep_internals.h | 1 -
 kernel/locking/lockdep_proc.c      | 2 +-
 3 files changed, 1 insertion(+), 7 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index a99fd5fade54..ce027d436651 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2978,11 +2978,6 @@ void trace_softirqs_on(unsigned long ip)
 	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
 		return;
 
-	if (curr->softirqs_enabled) {
-		debug_atomic_inc(redundant_softirqs_on);
-		return;
-	}
-
 	current->lockdep_recursion = 1;
 	/*
 	 * We'll do an OFF -> ON transition:
diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h
index 4b0c03f0f7ce..3401e4a91afb 100644
--- a/kernel/locking/lockdep_internals.h
+++ b/kernel/locking/lockdep_internals.h
@@ -186,7 +186,6 @@ struct lockdep_stats {
 	int	redundant_hardirqs_off;
 	int	softirqs_on_events;
 	int	softirqs_off_events;
-	int	redundant_softirqs_on;
 	int	redundant_softirqs_off;
 	int	nr_unused_locks;
 	int	nr_redundant_checks;
diff --git a/kernel/locking/lockdep_proc.c b/kernel/locking/lockdep_proc.c
index 3d31f9b0059e..4157560b36d2 100644
--- a/kernel/locking/lockdep_proc.c
+++ b/kernel/locking/lockdep_proc.c
@@ -169,7 +169,7 @@ static void lockdep_stats_debug_show(struct seq_file *m)
 			   hr2 = debug_atomic_read(redundant_hardirqs_off),
 			   si1 = debug_atomic_read(softirqs_on_events),
 			   si2 = debug_atomic_read(softirqs_off_events),
-			   sr1 = debug_atomic_read(redundant_softirqs_on),
+			   sr1 = 0,
 			   sr2 = debug_atomic_read(redundant_softirqs_off);
 
 	seq_printf(m, " chain lookup misses:           %11llu\n",
-- 
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 ` [PATCH 27/37] softirq: Check enabled vectors before processing Frederic Weisbecker
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 ` Frederic Weisbecker [this message]
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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