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[Qemu-devel] [PULL 15/19] linux-aio: queue requests that cannot be submi
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL 15/19] linux-aio: queue requests that cannot be submitted |
Date: |
Fri, 12 Dec 2014 17:10:01 +0000 |
From: Paolo Bonzini <address@hidden>
Keep a queue of requests that were not submitted; pass them to
the kernel when a completion is reported, unless the queue is
plugged.
The array of iocbs is rebuilt every time from scratch. This
avoids keeping the iocbs array and list synchronized.
Signed-off-by: Paolo Bonzini <address@hidden>
Reviewed-by: Kevin Wolf <address@hidden>
Message-id: address@hidden
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
block/linux-aio.c | 75 ++++++++++++++++++++++++-------------------------------
1 file changed, 33 insertions(+), 42 deletions(-)
diff --git a/block/linux-aio.c b/block/linux-aio.c
index d92513b..b6fbfd8 100644
--- a/block/linux-aio.c
+++ b/block/linux-aio.c
@@ -35,14 +35,13 @@ struct qemu_laiocb {
size_t nbytes;
QEMUIOVector *qiov;
bool is_read;
- QLIST_ENTRY(qemu_laiocb) node;
+ QSIMPLEQ_ENTRY(qemu_laiocb) next;
};
typedef struct {
- struct iocb *iocbs[MAX_QUEUED_IO];
int plugged;
- unsigned int size;
unsigned int idx;
+ QSIMPLEQ_HEAD(, qemu_laiocb) pending;
} LaioQueue;
struct qemu_laio_state {
@@ -59,6 +58,8 @@ struct qemu_laio_state {
int event_max;
};
+static int ioq_submit(struct qemu_laio_state *s);
+
static inline ssize_t io_event_ret(struct io_event *ev)
{
return (ssize_t)(((uint64_t)ev->res2 << 32) | ev->res);
@@ -135,6 +136,10 @@ static void qemu_laio_completion_bh(void *opaque)
qemu_laio_process_completion(s, laiocb);
}
+
+ if (!s->io_q.plugged && !QSIMPLEQ_EMPTY(&s->io_q.pending)) {
+ ioq_submit(s);
+ }
}
static void qemu_laio_completion_cb(EventNotifier *e)
@@ -172,52 +177,40 @@ static const AIOCBInfo laio_aiocb_info = {
static void ioq_init(LaioQueue *io_q)
{
- io_q->size = MAX_QUEUED_IO;
- io_q->idx = 0;
+ QSIMPLEQ_INIT(&io_q->pending);
io_q->plugged = 0;
+ io_q->idx = 0;
}
static int ioq_submit(struct qemu_laio_state *s)
{
- int ret, i = 0;
- int len = s->io_q.idx;
-
- do {
- ret = io_submit(s->ctx, len, s->io_q.iocbs);
- } while (i++ < 3 && ret == -EAGAIN);
+ int ret, i;
+ int len = 0;
+ struct qemu_laiocb *aiocb;
+ struct iocb *iocbs[MAX_QUEUED_IO];
- /* empty io queue */
- s->io_q.idx = 0;
+ QSIMPLEQ_FOREACH(aiocb, &s->io_q.pending, next) {
+ iocbs[len++] = &aiocb->iocb;
+ if (len == MAX_QUEUED_IO) {
+ break;
+ }
+ }
+ ret = io_submit(s->ctx, len, iocbs);
+ if (ret == -EAGAIN) {
+ ret = 0;
+ }
if (ret < 0) {
- i = 0;
- } else {
- i = ret;
+ abort();
}
- for (; i < len; i++) {
- struct qemu_laiocb *laiocb =
- container_of(s->io_q.iocbs[i], struct qemu_laiocb, iocb);
-
- laiocb->ret = (ret < 0) ? ret : -EIO;
- qemu_laio_process_completion(s, laiocb);
+ for (i = 0; i < ret; i++) {
+ s->io_q.idx--;
+ QSIMPLEQ_REMOVE_HEAD(&s->io_q.pending, next);
}
return ret;
}
-static void ioq_enqueue(struct qemu_laio_state *s, struct iocb *iocb)
-{
- unsigned int idx = s->io_q.idx;
-
- s->io_q.iocbs[idx++] = iocb;
- s->io_q.idx = idx;
-
- /* submit immediately if queue is full */
- if (idx == s->io_q.size) {
- ioq_submit(s);
- }
-}
-
void laio_io_plug(BlockDriverState *bs, void *aio_ctx)
{
struct qemu_laio_state *s = aio_ctx;
@@ -236,7 +229,7 @@ int laio_io_unplug(BlockDriverState *bs, void *aio_ctx,
bool unplug)
return 0;
}
- if (s->io_q.idx > 0) {
+ if (!QSIMPLEQ_EMPTY(&s->io_q.pending)) {
ret = ioq_submit(s);
}
@@ -276,12 +269,10 @@ BlockAIOCB *laio_submit(BlockDriverState *bs, void
*aio_ctx, int fd,
}
io_set_eventfd(&laiocb->iocb, event_notifier_get_fd(&s->e));
- if (!s->io_q.plugged) {
- if (io_submit(s->ctx, 1, &iocbs) < 0) {
- goto out_free_aiocb;
- }
- } else {
- ioq_enqueue(s, iocbs);
+ QSIMPLEQ_INSERT_TAIL(&s->io_q.pending, laiocb, next);
+ s->io_q.idx++;
+ if (s->io_q.idx == (s->io_q.plugged ? MAX_QUEUED_IO : 1)) {
+ ioq_submit(s);
}
return &laiocb->common;
--
2.1.0
- [Qemu-devel] [PULL 04/19] block/rbd: fix memory leak, (continued)
- [Qemu-devel] [PULL 04/19] block/rbd: fix memory leak, Stefan Hajnoczi, 2014/12/12
- [Qemu-devel] [PULL 05/19] block: vhdx - remove redundant comments, Stefan Hajnoczi, 2014/12/12
- [Qemu-devel] [PULL 06/19] block: vhdx - update PAYLOAD_BLOCK_UNMAPPED value to match 1.00 spec, Stefan Hajnoczi, 2014/12/12
- [Qemu-devel] [PULL 07/19] block: vhdx - change .vhdx_create default block state to ZERO, Stefan Hajnoczi, 2014/12/12
- [Qemu-devel] [PULL 08/19] qemu-io: Add sigraise command, Stefan Hajnoczi, 2014/12/12
- [Qemu-devel] [PULL 09/19] iotests: Filter for "Killed" in qemu-io output, Stefan Hajnoczi, 2014/12/12
- [Qemu-devel] [PULL 10/19] iotests: Fix test 039, Stefan Hajnoczi, 2014/12/12
- [Qemu-devel] [PULL 11/19] block: vhdx - set .bdrv_has_zero_init to bdrv_has_zero_init_1, Stefan Hajnoczi, 2014/12/12
- [Qemu-devel] [PULL 13/19] block: Don't add trailing space in "Formating..." message, Stefan Hajnoczi, 2014/12/12
- [Qemu-devel] [PULL 14/19] block: drop unused bdrv_clear_incoming_migration_all() prototype, Stefan Hajnoczi, 2014/12/12
- [Qemu-devel] [PULL 15/19] linux-aio: queue requests that cannot be submitted,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL 16/19] linux-aio: track whether the queue is blocked, Stefan Hajnoczi, 2014/12/12
- [Qemu-devel] [PULL 17/19] linux-aio: rename LaioQueue idx field to "n", Stefan Hajnoczi, 2014/12/12
- [Qemu-devel] [PULL 18/19] linux-aio: drop return code from laio_io_unplug and ioq_submit, Stefan Hajnoczi, 2014/12/12
- [Qemu-devel] [PULL 19/19] linux-aio: simplify removal of completed iocbs from the list, Stefan Hajnoczi, 2014/12/12
- [Qemu-devel] [PULL 12/19] qemu-iotests: Remove traling whitespaces in *.out, Stefan Hajnoczi, 2014/12/12
- Re: [Qemu-devel] [PULL 00/19] Block patches, Peter Maydell, 2014/12/15
- [Qemu-devel] [PULL 00/19] Block patches, Kevin Wolf, 2014/12/19