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[Qemu-devel] [PATCH 4/4] linux-aio: simplify removal of completed iocbs
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 4/4] linux-aio: simplify removal of completed iocbs from the list |
Date: |
Wed, 10 Dec 2014 15:52:02 +0100 |
There is no need to do another O(n) pass on the list; the iocb to
splice the list at is already available in the array we passed to
io_submit.
Signed-off-by: Paolo Bonzini <address@hidden>
---
block/linux-aio.c | 12 ++++++------
include/qemu/queue.h | 11 +++++++++++
2 files changed, 17 insertions(+), 6 deletions(-)
diff --git a/block/linux-aio.c b/block/linux-aio.c
index b223d9e..6c98f72 100644
--- a/block/linux-aio.c
+++ b/block/linux-aio.c
@@ -186,9 +186,10 @@ static void ioq_init(LaioQueue *io_q)
static int ioq_submit(struct qemu_laio_state *s)
{
- int ret, i, len;
+ int ret, len;
struct qemu_laiocb *aiocb;
struct iocb *iocbs[MAX_QUEUED_IO];
+ QSIMPLEQ_HEAD(, qemu_laiocb) completed;
do {
len = 0;
@@ -201,16 +202,15 @@ static int ioq_submit(struct qemu_laio_state *s)
ret = io_submit(s->ctx, len, iocbs);
if (ret == -EAGAIN) {
- ret = 0;
+ break;
}
if (ret < 0) {
abort();
}
- for (i = 0; i < ret; i++) {
- s->io_q.n--;
- QSIMPLEQ_REMOVE_HEAD(&s->io_q.pending, next);
- }
+ s->io_q.n -= ret;
+ aiocb = container_of(iocbs[ret - 1], struct qemu_laiocb, iocb);
+ QSIMPLEQ_SPLIT_AFTER(&completed, &s->io_q.pending, aiocb, next);
} while (ret == len && !QSIMPLEQ_EMPTY(&s->io_q.pending));
s->io_q.blocked = (s->io_q.n > 0);
diff --git a/include/qemu/queue.h b/include/qemu/queue.h
index 0dedd29..2c21d28 100644
--- a/include/qemu/queue.h
+++ b/include/qemu/queue.h
@@ -279,6 +279,17 @@ struct {
\
(head)->sqh_last = &(head)->sqh_first; \
} while (/*CONSTCOND*/0)
+#define QSIMPLEQ_SPLIT_AFTER(head1, head2, elm, field) do { \
+ if (((head1)->sqh_first = (head2)->sqh_first) == NULL) { \
+ (head1)->sqh_last = &(head1)->sqh_first; \
+ } else { \
+ (head1)->sqh_last = &(elm)->field.sqe_next; \
+ if (((head2)->sqh_first = (elm)->field.sqe_next) == NULL) { \
+ (head2)->sqh_last = &(head2)->sqh_first; \
+ } \
+ } \
+} while (/*CONSTCOND*/0)
+
#define QSIMPLEQ_REMOVE(head, elm, type, field) do { \
if ((head)->sqh_first == (elm)) { \
QSIMPLEQ_REMOVE_HEAD((head), field); \
--
2.1.0
[Qemu-devel] [PATCH 2/4] linux-aio: track whether the queue is blocked, Paolo Bonzini, 2014/12/10
[Qemu-devel] [PATCH 4/4] linux-aio: simplify removal of completed iocbs from the list,
Paolo Bonzini <=
[Qemu-devel] [PATCH 3/4] linux-aio: rename LaioQueue idx field to "n", Paolo Bonzini, 2014/12/10