Re: [Qemu-block] [PATCH 2/2] quorum: do not allocate multiple iovecs for FIFO strategy

[Alberto Garcia]

On Wed 05 Oct 2016 06:35:27 PM CEST, Paolo Bonzini wrote:
> In FIFO mode there are no parallel reads, hence there is no need to
> allocate separate buffers and clone the iovecs.
>
> The two cases of quorum_aio_cb are now even more different, and
> most of quorum_aio_finalize is only needed in one of them, so split
> them in separate functions.
>
> Signed-off-by: Paolo Bonzini 

Reviewed-by: Alberto Garcia 

Berto

Re: [Qemu-block] [PATCH 2/2] quorum: do not allocate multiple iovecs for FIFO strategy

[Max Reitz]

On 05.10.2016 18:35, Paolo Bonzini wrote:
> In FIFO mode there are no parallel reads, hence there is no need to
> allocate separate buffers and clone the iovecs.
> 
> The two cases of quorum_aio_cb are now even more different, and
> most of quorum_aio_finalize is only needed in one of them, so split
> them in separate functions.
> 
> Signed-off-by: Paolo Bonzini 
> ---
>  block/quorum.c | 79 
> +-
>  1 file changed, 40 insertions(+), 39 deletions(-)

Reviewed-by: Max Reitz 



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[Qemu-block] [PATCH 2/2] quorum: do not allocate multiple iovecs for FIFO strategy

[Paolo Bonzini]

In FIFO mode there are no parallel reads, hence there is no need to
allocate separate buffers and clone the iovecs.

The two cases of quorum_aio_cb are now even more different, and
most of quorum_aio_finalize is only needed in one of them, so split
them in separate functions.

Signed-off-by: Paolo Bonzini 
---
 block/quorum.c | 79 +-
 1 file changed, 40 insertions(+), 39 deletions(-)

diff --git a/block/quorum.c b/block/quorum.c
index 435296e..d122299 100644
--- a/block/quorum.c
+++ b/block/quorum.c
@@ -156,21 +156,7 @@ static AIOCBInfo quorum_aiocb_info = {
 
 static void quorum_aio_finalize(QuorumAIOCB *acb)
 {
-int i, ret = 0;
-
-if (acb->vote_ret) {
-ret = acb->vote_ret;
-}
-
-acb->common.cb(acb->common.opaque, ret);
-
-if (acb->is_read) {
-for (i = 0; i < acb->children_read; i++) {
-qemu_vfree(acb->qcrs[i].buf);
-qemu_iovec_destroy(>qcrs[i].qiov);
-}
-}
-
+acb->common.cb(acb->common.opaque, acb->vote_ret);
 g_free(acb->qcrs);
 qemu_aio_unref(acb);
 }
@@ -282,38 +268,52 @@ static void quorum_copy_qiov(QEMUIOVector *dest, 
QEMUIOVector *source)
 }
 }
 
-static void quorum_aio_cb(void *opaque, int ret)
+static void quorum_report_bad_acb(QuorumChildRequest *sacb, int ret)
+{
+QuorumAIOCB *acb = sacb->parent;
+QuorumOpType type = acb->is_read ? QUORUM_OP_TYPE_READ : 
QUORUM_OP_TYPE_WRITE;
+quorum_report_bad(type, acb->sector_num, acb->nb_sectors,
+  sacb->aiocb->bs->node_name, ret);
+}
+
+static void quorum_fifo_aio_cb(void *opaque, int ret)
 {
 QuorumChildRequest *sacb = opaque;
 QuorumAIOCB *acb = sacb->parent;
 BDRVQuorumState *s = acb->common.bs->opaque;
-bool rewrite = false;
 
-if (ret == 0) {
-acb->success_count++;
-} else {
-QuorumOpType type;
-type = acb->is_read ? QUORUM_OP_TYPE_READ : QUORUM_OP_TYPE_WRITE;
-quorum_report_bad(type, acb->sector_num, acb->nb_sectors,
-  sacb->aiocb->bs->node_name, ret);
-}
+assert(acb->is_read && s->read_pattern == QUORUM_READ_PATTERN_FIFO);
+
+if (ret < 0) {
+quorum_report_bad_acb(sacb, ret);
 
-if (acb->is_read && s->read_pattern == QUORUM_READ_PATTERN_FIFO) {
 /* We try to read next child in FIFO order if we fail to read */
-if (ret < 0 && acb->children_read < s->num_children) {
+if (acb->children_read < s->num_children) {
 read_fifo_child(acb);
 return;
 }
-
-if (ret == 0) {
-quorum_copy_qiov(acb->qiov, >qcrs[acb->children_read - 
1].qiov);
-}
-acb->vote_ret = ret;
-quorum_aio_finalize(acb);
-return;
 }
 
+acb->vote_ret = ret;
+
+/* FIXME: rewrite failed children if acb->children_read > 1? */
+quorum_aio_finalize(acb);
+}
+
+static void quorum_aio_cb(void *opaque, int ret)
+{
+QuorumChildRequest *sacb = opaque;
+QuorumAIOCB *acb = sacb->parent;
+BDRVQuorumState *s = acb->common.bs->opaque;
+bool rewrite = false;
+int i;
+
 sacb->ret = ret;
+if (ret == 0) {
+acb->success_count++;
+} else {
+quorum_report_bad_acb(sacb, ret);
+}
 acb->count++;
 assert(acb->count <= s->num_children);
 assert(acb->success_count <= s->num_children);
@@ -324,6 +324,10 @@ static void quorum_aio_cb(void *opaque, int ret)
 /* Do the vote on read */
 if (acb->is_read) {
 rewrite = quorum_vote(acb);
+for (i = 0; i < s->num_children; i++) {
+qemu_vfree(acb->qcrs[i].buf);
+qemu_iovec_destroy(>qcrs[i].qiov);
+}
 } else {
 quorum_has_too_much_io_failed(acb);
 }
@@ -672,12 +676,9 @@ static BlockAIOCB *read_fifo_child(QuorumAIOCB *acb)
 BDRVQuorumState *s = acb->common.bs->opaque;
 int n = acb->children_read++;
 
-acb->qcrs[n].buf = qemu_blockalign(s->children[n]->bs, acb->qiov->size);
-qemu_iovec_init(>qcrs[n].qiov, acb->qiov->niov);
-qemu_iovec_clone(>qcrs[n].qiov, acb->qiov, acb->qcrs[n].buf);
 acb->qcrs[n].aiocb = bdrv_aio_readv(s->children[n], acb->sector_num,
->qcrs[n].qiov, acb->nb_sectors,
-quorum_aio_cb, >qcrs[n]);
+acb->qiov, acb->nb_sectors,
+quorum_fifo_aio_cb, >qcrs[n]);
 
 return >common;
 }
-- 
2.7.4