From: Peter Zijlstra <peterz@infradead.org>
To: longman@redhat.com, mingo@redhat.com, will@kernel.org
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, boqun.feng@gmail.com
Subject: [PATCH 2/6] locking/rwsem: Enforce queueing when HANDOFF
Date: Thu, 23 Feb 2023 13:26:44 +0100 [thread overview]
Message-ID: <20230223123319.428168721@infradead.org> (raw)
In-Reply-To: 20230223122642.491637862@infradead.org
Ensure that HANDOFF disables all spinning and stealing.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/locking/rwsem.c | 9 +++++++++
1 file changed, 9 insertions(+)
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -468,7 +468,12 @@ static void rwsem_mark_wake(struct rw_se
adjustment -= RWSEM_FLAG_HANDOFF;
lockevent_inc(rwsem_rlock_handoff);
}
+ /*
+ * With HANDOFF set for reader, we must
+ * terminate all spinning.
+ */
waiter->handoff_set = true;
+ rwsem_set_nonspinnable(sem);
}
atomic_long_add(-adjustment, &sem->count);
@@ -755,6 +760,10 @@ rwsem_spin_on_owner(struct rw_semaphore
owner = rwsem_owner_flags(sem, &flags);
state = rwsem_owner_state(owner, flags);
+
+ if (owner == current)
+ return OWNER_NONSPINNABLE; /* Handoff granted */
+
if (state != OWNER_WRITER)
return state;
next prev parent reply other threads:[~2023-02-23 12:35 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-23 12:26 [PATCH 0/6] locking/rwsem: Rework writer wakeup and handoff Peter Zijlstra
2023-02-23 12:26 ` [PATCH 1/6] locking/rwsem: Minor code refactoring in rwsem_mark_wake() Peter Zijlstra
2023-02-23 12:26 ` Peter Zijlstra [this message]
2023-02-23 12:26 ` [PATCH 3/6] locking/rwsem: Rework writer wakeup Peter Zijlstra
2023-02-23 21:38 ` Waiman Long
2023-02-26 11:58 ` Peter Zijlstra
2023-02-26 12:00 ` Peter Zijlstra
2023-02-26 21:31 ` Waiman Long
2023-02-26 11:59 ` Peter Zijlstra
2023-02-26 15:04 ` Peter Zijlstra
2023-02-26 16:51 ` Peter Zijlstra
2023-02-27 0:22 ` Waiman Long
2023-02-27 10:31 ` Peter Zijlstra
2023-02-27 20:16 ` Waiman Long
2023-03-20 8:12 ` Peter Zijlstra
2023-03-20 17:36 ` Waiman Long
2023-02-23 12:26 ` [PATCH 4/6] locking/rwsem: Split out rwsem_reader_wake() Peter Zijlstra
2023-02-23 12:26 ` [PATCH 5/6] locking/rwsem: Unify wait loop Peter Zijlstra
2023-02-23 19:31 ` Boqun Feng
2023-02-24 1:33 ` Boqun Feng
2023-02-26 12:01 ` Peter Zijlstra
2023-02-26 18:22 ` Boqun Feng
2023-02-23 22:45 ` Waiman Long
2023-02-26 16:15 ` Peter Zijlstra
2023-02-23 12:26 ` [PATCH 6/6] locking/rwsem: Use the force Peter Zijlstra
2023-02-24 1:19 ` [PATCH 0/6] locking/rwsem: Rework writer wakeup and handoff Waiman Long
2023-02-24 11:55 ` Jiri Wiesner
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