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 10/13] locking/qspinlock: paravirt use simple trylock in case idx overflows
Date: Tue, 5 Jul 2022 00:38:17 +1000 [thread overview]
Message-ID: <20220704143820.3071004-11-npiggin@gmail.com> (raw)
In-Reply-To: <20220704143820.3071004-1-npiggin@gmail.com>
The mcs node overflow fallback locking case does not have to use
pv_hybrid_queued_unfair_trylock as the trylock, which reduces the
differences between pv and !pv cases.
This was likely an artifact of function renaming making it use the pv
trylock, which is not a bug but it is unexpected.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
kernel/locking/qspinlock.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c
index 1d5b3443772c..cef0ca7d94e1 100644
--- a/kernel/locking/qspinlock.c
+++ b/kernel/locking/qspinlock.c
@@ -798,13 +798,8 @@ static inline void queued_spin_lock_mcs_queue(struct qspinlock *lock, bool parav
*/
if (unlikely(idx >= MAX_NODES)) {
lockevent_inc(lock_no_node);
- if (paravirt) {
- while (!pv_hybrid_queued_unfair_trylock(lock))
- cpu_relax();
- } else {
- while (!queued_spin_trylock(lock))
- cpu_relax();
- }
+ while (!queued_spin_trylock(lock))
+ cpu_relax();
goto release;
}
--
2.35.1
next prev parent reply other threads:[~2022-07-04 14:39 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 ` Nicholas Piggin [this message]
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 ` [PATCH 12/13] locking/qspinlock: separate pv_wait_node from the non-paravirt path Nicholas Piggin
2022-07-05 17:34 ` 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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