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From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-devel@nongnu.org
Cc: Akihiko Odaki <akihiko.odaki@daynix.com>
Subject: [PULL 22/31] qemu-thread: Use futex if available for QemuLockCnt
Date: Fri,  6 Jun 2025 14:34:36 +0200	[thread overview]
Message-ID: <20250606123447.538131-23-pbonzini@redhat.com> (raw)
In-Reply-To: <20250606123447.538131-1-pbonzini@redhat.com>

From: Akihiko Odaki <akihiko.odaki@daynix.com>

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

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Link: https://lore.kernel.org/r/20250529-event-v5-6-53b285203794@daynix.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.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 f4b62a3f701..5a2800e3f18 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 ca27d8e61a5..92c9f8ceca8 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:[~2025-06-06 12:39 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-06-06 12:34 [PULL 00/31] Threading, Rust, i386 changes for 2025-06-06 Paolo Bonzini
2025-06-06 12:34 ` [PULL 01/31] subprojects: add the anyhow crate Paolo Bonzini
2025-06-06 12:34 ` [PULL 02/31] subprojects: add the foreign crate Paolo Bonzini
2025-06-06 12:34 ` [PULL 03/31] util/error: expose Error definition to Rust code Paolo Bonzini
2025-06-06 12:34 ` [PULL 04/31] util/error: allow non-NUL-terminated err->src Paolo Bonzini
2025-06-06 12:34 ` [PULL 05/31] util/error: make func optional Paolo Bonzini
2025-06-06 12:34 ` [PULL 06/31] rust: qemu-api: add bindings to Error Paolo Bonzini
2025-06-06 12:34 ` [PULL 07/31] rust: qemu-api: add tests for Error bindings Paolo Bonzini
2025-06-06 12:34 ` [PULL 08/31] rust: qdev: support returning errors from realize Paolo Bonzini
2025-06-06 12:34 ` [PULL 09/31] rust/hpet: change type of num_timers to usize Paolo Bonzini
2025-06-06 12:34 ` [PULL 10/31] hpet: adjust VMState for consistency with Rust version Paolo Bonzini
2025-06-06 12:34 ` [PULL 11/31] hpet: return errors from realize if properties are incorrect Paolo Bonzini
2025-06-06 12:34 ` [PULL 12/31] rust/hpet: " Paolo Bonzini
2025-06-06 12:34 ` [PULL 13/31] rust/hpet: Drop BqlCell wrapper for num_timers Paolo Bonzini
2025-06-06 12:34 ` [PULL 14/31] docs: update Rust module status Paolo Bonzini
2025-06-06 12:34 ` [PULL 15/31] rust: make TryFrom macro more resilient Paolo Bonzini
2025-06-06 12:34 ` [PULL 16/31] i386/kvm: Prefault memory on page state change Paolo Bonzini
2025-06-11  2:55   ` Xiaoyao Li
2025-06-11  6:12     ` Paolo Bonzini
2025-06-11  6:44       ` Xiaoyao Li
2025-06-06 12:34 ` [PULL 17/31] futex: Check value after qemu_futex_wait() Paolo Bonzini
2025-06-06 12:34 ` [PULL 18/31] futex: Support Windows Paolo Bonzini
2025-06-06 12:34 ` [PULL 19/31] qemu-thread: Replace __linux__ with CONFIG_LINUX Paolo Bonzini
2025-06-06 12:34 ` [PULL 20/31] qemu-thread: Avoid futex abstraction for non-Linux Paolo Bonzini
2025-06-06 12:34 ` [PULL 21/31] qemu-thread: Use futex for QemuEvent on Windows Paolo Bonzini
2025-06-06 12:34 ` Paolo Bonzini [this message]
2025-06-06 12:34 ` [PULL 23/31] qemu-thread: Document QemuEvent Paolo Bonzini
2025-06-06 12:34 ` [PULL 24/31] migration: Replace QemuSemaphore with QemuEvent Paolo Bonzini
2025-06-06 12:34 ` [PULL 25/31] migration/colo: " Paolo Bonzini
2025-06-06 12:34 ` [PULL 26/31] migration/postcopy: " Paolo Bonzini
2025-06-06 12:34 ` [PULL 27/31] hw/display/apple-gfx: " Paolo Bonzini
2025-06-06 12:34 ` [PULL 28/31] target/i386: Detect flush-to-zero after rounding Paolo Bonzini
2025-06-06 12:34 ` [PULL 29/31] target/i386: Use correct type for get_float_exception_flags() values Paolo Bonzini
2025-06-06 12:34 ` [PULL 30/31] target/i386: Wire up MXCSR.DE and FPUS.DE correctly Paolo Bonzini
2025-06-06 12:34 ` [PULL 31/31] tests/tcg/x86_64/fma: add test for exact-denormal output Paolo Bonzini
2025-06-06 15:27 ` [PULL 00/31] Threading, Rust, i386 changes for 2025-06-06 Stefan Hajnoczi

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