From 81d3dc9a349b1e61d77106bbb05a6e6dd29b9d5e Mon Sep 17 00:00:00 2001 From: Waiman Long Date: Thu, 26 Apr 2018 11:34:27 +0100 Subject: locking/qspinlock: Add stat tracking for pending vs. slowpath Currently, the qspinlock_stat code tracks only statistical counts in the PV qspinlock code. However, it may also be useful to track the number of locking operations done via the pending code vs. the MCS lock queue slowpath for the non-PV case. The qspinlock stat code is modified to do that. The stat counter pv_lock_slowpath is renamed to lock_slowpath so that it can be used by both the PV and non-PV cases. Signed-off-by: Waiman Long Acked-by: Peter Zijlstra (Intel) Acked-by: Waiman Long Cc: Linus Torvalds Cc: Thomas Gleixner Cc: boqun.feng@gmail.com Cc: linux-arm-kernel@lists.infradead.org Cc: paulmck@linux.vnet.ibm.com Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1524738868-31318-14-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar --- kernel/locking/qspinlock.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) (limited to 'kernel/locking/qspinlock.c') diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 46813185957b..bfaeb05123ff 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -12,11 +12,11 @@ * GNU General Public License for more details. * * (C) Copyright 2013-2015 Hewlett-Packard Development Company, L.P. - * (C) Copyright 2013-2014 Red Hat, Inc. + * (C) Copyright 2013-2014,2018 Red Hat, Inc. * (C) Copyright 2015 Intel Corp. * (C) Copyright 2015 Hewlett-Packard Enterprise Development LP * - * Authors: Waiman Long + * Authors: Waiman Long * Peter Zijlstra */ @@ -32,6 +32,11 @@ #include #include +/* + * Include queued spinlock statistics code + */ +#include "qspinlock_stat.h" + /* * The basic principle of a queue-based spinlock can best be understood * by studying a classic queue-based spinlock implementation called the @@ -295,7 +300,7 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) BUILD_BUG_ON(CONFIG_NR_CPUS >= (1U << _Q_TAIL_CPU_BITS)); if (pv_enabled()) - goto queue; + goto pv_queue; if (virt_spin_lock(lock)) return; @@ -348,6 +353,7 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) * *,1,0 -> *,0,1 */ clear_pending_set_locked(lock); + qstat_inc(qstat_lock_pending, true); return; } @@ -363,6 +369,8 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) * queuing. */ queue: + qstat_inc(qstat_lock_slowpath, true); +pv_queue: node = this_cpu_ptr(&mcs_nodes[0]); idx = node->count++; tail = encode_tail(smp_processor_id(), idx); -- cgit v1.2.3