aboutsummaryrefslogtreecommitdiff
path: root/include
diff options
context:
space:
mode:
authorPaolo Bonzini <pbonzini@redhat.com>2014-12-02 12:05:47 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2015-01-13 13:43:29 +0000
commitc740ad92d0d958fa785e5d7aa1b67ecaf30a6a54 (patch)
tree9294b5dcdf00456ad6f8823ef7891d76ff45e003 /include
parent6d86ae0824bdd6175dd3874688a871e981093888 (diff)
QSLIST: add lock-free operations
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 <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 1417518350-6167-5-git-send-email-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'include')
-rw-r--r--include/qemu/queue.h15
1 files changed, 13 insertions, 2 deletions
diff --git a/include/qemu/queue.h b/include/qemu/queue.h
index 42bcadfbb1..a98eb3ad79 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 { \