From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
Marc Zyngier <maz@kernel.org>,
Oliver Upton <oliver.upton@linux.dev>,
Sean Christopherson <seanjc@google.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev,
K Prateek Nayak <kprateek.nayak@amd.com>,
David Matlack <dmatlack@google.com>,
Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Subject: [PATCH v2 08/12] sched/wait: Drop WQ_FLAG_EXCLUSIVE from add_wait_queue_priority()
Date: Mon, 19 May 2025 11:55:10 -0700 [thread overview]
Message-ID: <20250519185514.2678456-9-seanjc@google.com> (raw)
In-Reply-To: <20250519185514.2678456-1-seanjc@google.com>
Drop the setting of WQ_FLAG_EXCLUSIVE from add_wait_queue_priority() to
differentiate it from add_wait_queue_priority_exclusive(). The one and
only user add_wait_queue_priority(), Xen privcmd's irqfd_wakeup(),
unconditionally returns '0', i.e. doesn't actually operate in exclusive
mode.
Cc: Juergen Gross <jgross@suse.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
kernel/sched/wait.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
index 03252badb8e8..b8f6502372b0 100644
--- a/kernel/sched/wait.c
+++ b/kernel/sched/wait.c
@@ -40,7 +40,7 @@ void add_wait_queue_priority(struct wait_queue_head *wq_head, struct wait_queue_
{
unsigned long flags;
- wq_entry->flags |= WQ_FLAG_EXCLUSIVE | WQ_FLAG_PRIORITY;
+ wq_entry->flags |= WQ_FLAG_PRIORITY;
spin_lock_irqsave(&wq_head->lock, flags);
__add_wait_queue(wq_head, wq_entry);
spin_unlock_irqrestore(&wq_head->lock, flags);
@@ -82,7 +82,7 @@ EXPORT_SYMBOL(remove_wait_queue);
* the non-exclusive tasks. Normally, exclusive tasks will be at the end of
* the list and any non-exclusive tasks will be woken first. A priority task
* may be at the head of the list, and can consume the event without any other
- * tasks being woken.
+ * tasks being woken if it's also an exclusive task.
*
* There are circumstances in which we can try to wake a task which has already
* started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
--
2.49.0.1101.gccaa498523-goog
next prev parent reply other threads:[~2025-05-19 18:55 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-19 18:55 [PATCH v2 00/12] KVM: Make irqfd registration globally unique Sean Christopherson
2025-05-19 18:55 ` [PATCH v2 01/12] KVM: Use a local struct to do the initial vfs_poll() on an irqfd Sean Christopherson
2025-05-19 18:55 ` [PATCH v2 02/12] KVM: Acquire SCRU lock outside of irqfds.lock during assignment Sean Christopherson
2025-05-19 18:55 ` [PATCH v2 03/12] KVM: Initialize irqfd waitqueue callback when adding to the queue Sean Christopherson
2025-05-19 18:55 ` [PATCH v2 04/12] KVM: Add irqfd to KVM's list via the vfs_poll() callback Sean Christopherson
2025-05-19 18:55 ` [PATCH v2 05/12] KVM: Add irqfd to eventfd's waitqueue while holding irqfds.lock Sean Christopherson
2025-05-19 18:55 ` [PATCH v2 06/12] sched/wait: Add a waitqueue helper for fully exclusive priority waiters Sean Christopherson
2025-05-20 19:17 ` Peter Zijlstra
2025-05-20 20:57 ` Sean Christopherson
2025-05-19 18:55 ` [PATCH v2 07/12] KVM: Disallow binding multiple irqfds to an eventfd with a priority waiter Sean Christopherson
2025-05-19 18:55 ` Sean Christopherson [this message]
2025-05-20 19:18 ` [PATCH v2 08/12] sched/wait: Drop WQ_FLAG_EXCLUSIVE from add_wait_queue_priority() Peter Zijlstra
2025-05-20 22:20 ` Sean Christopherson
2025-05-21 11:42 ` Peter Zijlstra
2025-05-21 14:44 ` Michael Kelley
2025-05-21 15:05 ` Sean Christopherson
2025-05-21 13:22 ` Jürgen Groß
2025-05-19 18:55 ` [PATCH v2 09/12] KVM: Drop sanity check that per-VM list of irqfds is unique Sean Christopherson
2025-05-19 18:55 ` [PATCH v2 10/12] KVM: selftests: Assert that eventfd() succeeds in Xen shinfo test Sean Christopherson
2025-05-19 18:55 ` [PATCH v2 11/12] KVM: selftests: Add utilities to create eventfds and do KVM_IRQFD Sean Christopherson
2025-05-19 18:55 ` [PATCH v2 12/12] KVM: selftests: Add a KVM_IRQFD test to verify uniqueness requirements Sean Christopherson
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