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
next prev 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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