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[Qemu-devel] [PULL v2 34/44] QSLIST: add lock-free operations
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL v2 34/44] QSLIST: add lock-free operations |
Date: |
Mon, 12 Jan 2015 16:40:24 +0000 |
From: Paolo Bonzini <address@hidden>
These operations are trivial to implement and do not have ABA problems.
They are enough to implement simple multiple-producer, single consumer
lock-free lists or, as in the next patch, the multiple consumers can
steal a whole batch of elements and process them at their leisure.
Signed-off-by: Paolo Bonzini <address@hidden>
Reviewed-by: Fam Zheng <address@hidden>
Message-id: address@hidden
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
include/qemu/queue.h | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/include/qemu/queue.h b/include/qemu/queue.h
index 42bcadf..a98eb3a 100644
--- a/include/qemu/queue.h
+++ b/include/qemu/queue.h
@@ -191,8 +191,19 @@ struct {
\
} while (/*CONSTCOND*/0)
#define QSLIST_INSERT_HEAD(head, elm, field) do { \
- (elm)->field.sle_next = (head)->slh_first; \
- (head)->slh_first = (elm); \
+ (elm)->field.sle_next = (head)->slh_first; \
+ (head)->slh_first = (elm); \
+} while (/*CONSTCOND*/0)
+
+#define QSLIST_INSERT_HEAD_ATOMIC(head, elm, field) do { \
+ do { \
+ (elm)->field.sle_next = (head)->slh_first; \
+ } while (atomic_cmpxchg(&(head)->slh_first, (elm)->field.sle_next, \
+ (elm)) != (elm)->field.sle_next); \
+} while (/*CONSTCOND*/0)
+
+#define QSLIST_MOVE_ATOMIC(dest, src) do { \
+ (dest)->slh_first = atomic_xchg(&(src)->slh_first, NULL); \
} while (/*CONSTCOND*/0)
#define QSLIST_REMOVE_HEAD(head, field) do { \
--
2.1.0
- [Qemu-devel] [PULL v2 00/44] Block patches, Stefan Hajnoczi, 2015/01/12
- [Qemu-devel] [PULL v2 32/44] qemu-thread: add per-thread atexit functions, Stefan Hajnoczi, 2015/01/12
- [Qemu-devel] [PULL v2 33/44] test-coroutine: avoid overflow on 32-bit systems, Stefan Hajnoczi, 2015/01/12
- [Qemu-devel] [PULL v2 34/44] QSLIST: add lock-free operations,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL v2 35/44] coroutine: rewrite pool to avoid mutex, Stefan Hajnoczi, 2015/01/12
- [Qemu-devel] [PULL v2 26/44] block/raw-posix.c: Fixes raw_getlength() on Mac OS X so that it reports the correct length of a real CD, Stefan Hajnoczi, 2015/01/12
- [Qemu-devel] [PULL v2 36/44] coroutine: drop qemu_coroutine_adjust_pool_size, Stefan Hajnoczi, 2015/01/12
- [Qemu-devel] [PULL v2 25/44] libqos: Add virtio MMIO support, Stefan Hajnoczi, 2015/01/12
- [Qemu-devel] [PULL v2 21/44] libqos: Change use of pointers to uint64_t in virtio, Stefan Hajnoczi, 2015/01/12
- [Qemu-devel] [PULL v2 24/44] libqos: Add malloc generic, Stefan Hajnoczi, 2015/01/12
- [Qemu-devel] [PULL v2 39/44] block: Split BLOCK_OP_TYPE_COMMIT to BLOCK_OP_TYPE_COMMIT_{SOURCE, TARGET}, Stefan Hajnoczi, 2015/01/12
- [Qemu-devel] [PULL v2 20/44] libqos: Convert malloc-pc allocator to a generic allocator, Stefan Hajnoczi, 2015/01/12
- [Qemu-devel] [PULL v2 23/44] libqos: Remove PCI assumptions in constants of virtio driver, Stefan Hajnoczi, 2015/01/12
- [Qemu-devel] [PULL v2 38/44] block: limited request size in write zeroes unsupported path, Stefan Hajnoczi, 2015/01/12