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From: Akihiko Odaki <akihiko.odaki@daynix.com>
To: Paolo Bonzini <pbonzini@redhat.com>, Stefan Weil <sw@weilnetz.de>,
	 Peter Xu <peterx@redhat.com>, Fabiano Rosas <farosas@suse.de>,
	 Hailiang Zhang <zhanghailiang@xfusion.com>
Cc: "Phil Dennis-Jordan" <phil@philjordan.eu>,
	qemu-devel@nongnu.org, devel@daynix.com,
	"Marc-André Lureau" <marcandre.lureau@redhat.com>,
	"Daniel P. Berrangé" <berrange@redhat.com>,
	"Philippe Mathieu-Daudé" <philmd@linaro.org>,
	"Akihiko Odaki" <akihiko.odaki@daynix.com>
Subject: [PATCH v4 07/11] qemu-thread: Use futex if available for QemuLockCnt
Date: Mon, 26 May 2025 14:29:17 +0900	[thread overview]
Message-ID: <20250526-event-v4-7-5b784cc8e1de@daynix.com> (raw)
In-Reply-To: <20250526-event-v4-0-5b784cc8e1de@daynix.com>

This unlocks the futex-based implementation of QemuLockCnt to Windows.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 include/qemu/lockcnt.h | 2 +-
 util/lockcnt.c         | 7 ++++---
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/include/qemu/lockcnt.h b/include/qemu/lockcnt.h
index f4b62a3f7011..5a2800e3f182 100644
--- a/include/qemu/lockcnt.h
+++ b/include/qemu/lockcnt.h
@@ -17,7 +17,7 @@
 typedef struct QemuLockCnt QemuLockCnt;
 
 struct QemuLockCnt {
-#ifndef CONFIG_LINUX
+#ifndef HAVE_FUTEX
     QemuMutex mutex;
 #endif
     unsigned count;
diff --git a/util/lockcnt.c b/util/lockcnt.c
index ca27d8e61a5c..92c9f8ceca88 100644
--- a/util/lockcnt.c
+++ b/util/lockcnt.c
@@ -12,10 +12,11 @@
 #include "qemu/atomic.h"
 #include "trace.h"
 
-#ifdef CONFIG_LINUX
-#include "qemu/futex.h"
+#ifdef HAVE_FUTEX
 
-/* On Linux, bits 0-1 are a futex-based lock, bits 2-31 are the counter.
+/*
+ * When futex is available, bits 0-1 are a futex-based lock, bits 2-31 are the
+ * counter.
  * For the mutex algorithm see Ulrich Drepper's "Futexes Are Tricky" (ok,
  * this is not the most relaxing citation I could make...).  It is similar
  * to mutex2 in the paper.

-- 
2.49.0



  parent reply	other threads:[~2025-05-26  5:31 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-26  5:29 [PATCH v4 00/11] Improve futex usage Akihiko Odaki
2025-05-26  5:29 ` [PATCH v4 01/11] futex: Check value after qemu_futex_wait() Akihiko Odaki
2025-05-26  5:29 ` [PATCH v4 02/11] futex: Support Windows Akihiko Odaki
2025-05-26  5:29 ` [PATCH v4 03/11] qemu-thread: Remove qatomic_read() in qemu_event_set() Akihiko Odaki
2025-05-26  5:29 ` [PATCH v4 04/11] qemu-thread: Replace __linux__ with CONFIG_LINUX Akihiko Odaki
2025-05-26  9:09   ` Philippe Mathieu-Daudé
2025-05-26  5:29 ` [PATCH v4 05/11] qemu-thread: Avoid futex abstraction for non-Linux Akihiko Odaki
2025-05-26  5:29 ` [PATCH v4 06/11] qemu-thread: Use futex for QemuEvent on Windows Akihiko Odaki
2025-05-26  9:23   ` Philippe Mathieu-Daudé
2025-05-26  5:29 ` Akihiko Odaki [this message]
2025-05-26  5:29 ` [PATCH v4 08/11] migration: Replace QemuSemaphore with QemuEvent Akihiko Odaki
2025-05-26  9:24   ` Philippe Mathieu-Daudé
2025-05-26  5:29 ` [PATCH v4 09/11] migration/colo: " Akihiko Odaki
2025-05-26  9:24   ` Philippe Mathieu-Daudé
2025-05-26  5:29 ` [PATCH v4 10/11] migration/postcopy: " Akihiko Odaki
2025-05-26  5:29 ` [PATCH v4 11/11] hw/display/apple-gfx: " Akihiko Odaki
2025-05-26  9:27   ` Philippe Mathieu-Daudé
2025-05-26  9:29     ` Philippe Mathieu-Daudé
2025-05-29  4:49       ` Akihiko Odaki
2025-05-26 14:48 ` [PATCH v4 00/11] Improve futex usage Peter Xu
2025-05-27  2:09   ` Akihiko Odaki
2025-05-27 13:46     ` Peter Xu
2025-05-28  3:30       ` Akihiko Odaki
2025-05-26 16:51 ` Paolo Bonzini
2025-05-27  3:00   ` Akihiko Odaki
2025-05-27 15:01     ` Paolo Bonzini
2025-05-28  3:26       ` Akihiko Odaki

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