From: Nicholas Piggin <npiggin@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Nicholas Piggin <npiggin@gmail.com>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
Waiman Long <longman@redhat.com>,
Boqun Feng <boqun.feng@gmail.com>,
linux-kernel@vger.kernel.org
Subject: [PATCH 12/13] locking/qspinlock: separate pv_wait_node from the non-paravirt path
Date: Tue, 5 Jul 2022 00:38:19 +1000 [thread overview]
Message-ID: <20220704143820.3071004-13-npiggin@gmail.com> (raw)
In-Reply-To: <20220704143820.3071004-1-npiggin@gmail.com>
pv_wait_node waits until node->locked is non-zero, no need for the
pv case to wait again by also executing the !pv code path.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
kernel/locking/qspinlock.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c
index 9db168753124..19e2f286be0a 100644
--- a/kernel/locking/qspinlock.c
+++ b/kernel/locking/qspinlock.c
@@ -862,10 +862,11 @@ static inline void queued_spin_lock_mcs_queue(struct qspinlock *lock, bool parav
/* Link @node into the waitqueue. */
WRITE_ONCE(prev->next, node);
+ /* Wait for mcs node lock to be released */
if (paravirt)
pv_wait_node(node, prev);
- /* Wait for mcs node lock to be released */
- smp_cond_load_acquire(&node->locked, VAL);
+ else
+ smp_cond_load_acquire(&node->locked, VAL);
/*
* While waiting for the MCS lock, the next pointer may have
--
2.35.1
next prev parent reply other threads:[~2022-07-04 14:40 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-04 14:38 [PATCH 00/13] locking/qspinlock: simplify code generation Nicholas Piggin
2022-07-04 14:38 ` [PATCH 01/13] locking/qspinlock: remove pv_node abstraction Nicholas Piggin
2022-07-06 23:23 ` Boqun Feng
2022-07-04 14:38 ` [PATCH 02/13] locking/qspinlock: inline mcs_spinlock functions into qspinlock Nicholas Piggin
2022-07-05 16:57 ` Peter Zijlstra
2022-07-12 0:06 ` Nicholas Piggin
2022-07-04 14:38 ` [PATCH 03/13] locking/qspinlock: split common mcs queueing code into its own function Nicholas Piggin
2022-07-05 17:01 ` Peter Zijlstra
2022-07-12 0:10 ` Nicholas Piggin
2022-07-04 14:38 ` [PATCH 04/13] locking/qspinlock: move pv lock word helpers into qspinlock.c Nicholas Piggin
2022-07-05 19:34 ` Waiman Long
2022-07-12 0:11 ` Nicholas Piggin
2022-07-04 14:38 ` [PATCH 05/13] locking/qspinlock: be less clever with the preprocessor Nicholas Piggin
2022-07-05 17:08 ` Peter Zijlstra
2022-07-12 0:29 ` Nicholas Piggin
2022-07-05 20:02 ` Waiman Long
2022-07-12 0:33 ` Nicholas Piggin
2022-07-04 14:38 ` [PATCH 06/13] locking/qspinlock: merge qspinlock_paravirt.h into qspinlock.c Nicholas Piggin
2022-07-05 17:20 ` Peter Zijlstra
2022-07-05 17:36 ` Peter Zijlstra
2022-07-12 0:46 ` Nicholas Piggin
2022-07-06 13:35 ` Waiman Long
2022-07-06 14:16 ` Peter Zijlstra
2022-07-04 14:38 ` [PATCH 07/13] locking/qspinlock: remove arch qspinlock_paravirt.h includes Nicholas Piggin
2022-07-04 14:38 ` [PATCH 08/13] locking/qspinlock: stop renaming queued_spin_lock_slowpath to native_queued_spin_lock_slowpath Nicholas Piggin
2022-07-05 17:28 ` Peter Zijlstra
2022-07-04 14:38 ` [PATCH 09/13] locking/qspinlock: rename __pv_init_lock_hash to pv_spinlocks_init Nicholas Piggin
2022-07-04 14:38 ` [PATCH 10/13] locking/qspinlock: paravirt use simple trylock in case idx overflows Nicholas Piggin
2022-07-04 14:38 ` [PATCH 11/13] locking/qspinlock: Use queued_spin_trylock in pv_hybrid_queued_unfair_trylock Nicholas Piggin
2022-07-05 17:31 ` Peter Zijlstra
2022-07-05 20:15 ` Waiman Long
2022-07-12 0:48 ` Nicholas Piggin
2022-07-04 14:38 ` Nicholas Piggin [this message]
2022-07-05 17:34 ` [PATCH 12/13] locking/qspinlock: separate pv_wait_node from the non-paravirt path Peter Zijlstra
2022-07-12 0:50 ` Nicholas Piggin
2022-07-04 14:38 ` [PATCH 13/13] locking/qspinlock: simplify pv_wait_head_or_lock calling scheme Nicholas Piggin
2022-07-05 17:59 ` [PATCH 00/13] locking/qspinlock: simplify code generation Peter Zijlstra
2022-07-12 0:56 ` Nicholas Piggin
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