[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH v4 06/14] qemu-thread: add simple test-and-set spinl
From: |
Emilio G. Cota |
Subject: |
[Qemu-devel] [PATCH v4 06/14] qemu-thread: add simple test-and-set spinlock |
Date: |
Fri, 29 Apr 2016 23:33:09 -0400 |
From: Guillaume Delbergue <address@hidden>
Signed-off-by: Guillaume Delbergue <address@hidden>
[Rewritten. - Paolo]
Signed-off-by: Paolo Bonzini <address@hidden>
[Emilio's additions: use atomic_test_and_set instead of atomic_xchg;
call cpu_relax() while spinning; optimize for uncontended locks by
acquiring the lock with TAS instead of TATAS.]
Signed-off-by: Emilio G. Cota <address@hidden>
---
include/qemu/thread.h | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/include/qemu/thread.h b/include/qemu/thread.h
index bdae6df..39ff1ac 100644
--- a/include/qemu/thread.h
+++ b/include/qemu/thread.h
@@ -1,6 +1,9 @@
#ifndef __QEMU_THREAD_H
#define __QEMU_THREAD_H 1
+#include <errno.h>
+#include "qemu/processor.h"
+#include "qemu/atomic.h"
typedef struct QemuMutex QemuMutex;
typedef struct QemuCond QemuCond;
@@ -60,4 +63,35 @@ struct Notifier;
void qemu_thread_atexit_add(struct Notifier *notifier);
void qemu_thread_atexit_remove(struct Notifier *notifier);
+typedef struct QemuSpin {
+ int value;
+} QemuSpin;
+
+static inline void qemu_spin_init(QemuSpin *spin)
+{
+ spin->value = 0;
+}
+
+static inline void qemu_spin_lock(QemuSpin *spin)
+{
+ while (atomic_test_and_set(&spin->value)) {
+ while (atomic_read(&spin->value)) {
+ cpu_relax();
+ }
+ }
+}
+
+static inline int qemu_spin_trylock(QemuSpin *spin)
+{
+ if (atomic_test_and_set(&spin->value)) {
+ return -EBUSY;
+ }
+ return 0;
+}
+
+static inline void qemu_spin_unlock(QemuSpin *spin)
+{
+ atomic_mb_set(&spin->value, 0);
+}
+
#endif
--
2.5.0
- [Qemu-devel] [PATCH v4 00/14] tb hash improvements, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 01/14] compiler.h: add QEMU_ALIGNED() to enforce struct alignment, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 04/14] include/processor.h: define cpu_relax(), Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 08/14] tb hash: hash phys_pc, pc, and flags with xxhash, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 03/14] seqlock: rename write_lock/unlock to write_begin/end, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 10/14] qdist: add test program, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 05/14] atomics: add atomic_test_and_set, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 11/14] qht: QEMU's fast, resizable and scalable Hash Table, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 06/14] qemu-thread: add simple test-and-set spinlock,
Emilio G. Cota <=
- [Qemu-devel] [PATCH v4 14/14] translate-all: add tb hash bucket info to 'info jit' dump, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 02/14] seqlock: remove optional mutex, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 07/14] exec: add tb_hash_func5, derived from xxhash, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 12/14] qht: add test program, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 13/14] tb hash: track translated blocks with qht, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 09/14] qdist: add module to represent frequency distributions of data, Emilio G. Cota, 2016/04/29