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authorOrit Wasserman <owasserm@redhat.com>2013-03-22 16:48:00 +0200
committerJuan Quintela <quintela@redhat.com>2013-03-26 13:32:33 +0100
commitb3ea2bdb792f6d961ba3adf45cf1f0c63c61e09d (patch)
treeba1b0f19b37d38c8a6c3e977993593648b0ab3b9 /savevm.c
parent7d8a30bb98e89c203b3d2289ab0638c38bbeb7c1 (diff)
downloadqemu-arm-b3ea2bdb792f6d961ba3adf45cf1f0c63c61e09d.tar.gz
Store the data to send also in iovec
All data is still copied into the static buffer. Adjacent iovecs are coalesced so we send one big buffer instead of many small buffers. Signed-off-by: Orit Wasserman <owasserm@redhat.com> Signed-off-by: Juan Quintela <quintela@redhat.com>
Diffstat (limited to 'savevm.c')
-rw-r--r--savevm.c24
1 files changed, 22 insertions, 2 deletions
diff --git a/savevm.c b/savevm.c
index 5ab256c97d..aaaf39a678 100644
--- a/savevm.c
+++ b/savevm.c
@@ -114,6 +114,7 @@ void qemu_announce_self(void)
/* savevm/loadvm support */
#define IO_BUF_SIZE 32768
+#define MAX_IOV_SIZE MIN(IOV_MAX, 64)
struct QEMUFile {
const QEMUFileOps *ops;
@@ -129,6 +130,9 @@ struct QEMUFile {
int buf_size; /* 0 when writing */
uint8_t buf[IO_BUF_SIZE];
+ struct iovec iov[MAX_IOV_SIZE];
+ unsigned int iovcnt;
+
int last_error;
};
@@ -528,6 +532,7 @@ static void qemu_fflush(QEMUFile *f)
f->pos += f->buf_index;
}
f->buf_index = 0;
+ f->iovcnt = 0;
}
if (ret < 0) {
qemu_file_set_error(f, ret);
@@ -601,6 +606,18 @@ int qemu_fclose(QEMUFile *f)
return ret;
}
+static void add_to_iovec(QEMUFile *f, const uint8_t *buf, int size)
+{
+ /* check for adjacent buffer and coalesce them */
+ if (f->iovcnt > 0 && buf == f->iov[f->iovcnt - 1].iov_base +
+ f->iov[f->iovcnt - 1].iov_len) {
+ f->iov[f->iovcnt - 1].iov_len += size;
+ } else {
+ f->iov[f->iovcnt].iov_base = (uint8_t *)buf;
+ f->iov[f->iovcnt++].iov_len = size;
+ }
+}
+
void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size)
{
int l;
@@ -620,12 +637,13 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, int size)
if (l > size)
l = size;
memcpy(f->buf + f->buf_index, buf, l);
+ add_to_iovec(f, f->buf + f->buf_index, l);
f->is_write = 1;
f->buf_index += l;
f->bytes_xfer += l;
buf += l;
size -= l;
- if (f->buf_index >= IO_BUF_SIZE) {
+ if (f->buf_index >= IO_BUF_SIZE || f->iovcnt >= MAX_IOV_SIZE) {
qemu_fflush(f);
if (qemu_file_get_error(f)) {
break;
@@ -650,7 +668,9 @@ void qemu_put_byte(QEMUFile *f, int v)
f->is_write = 1;
f->bytes_xfer++;
- if (f->buf_index >= IO_BUF_SIZE) {
+ add_to_iovec(f, f->buf + (f->buf_index - 1), 1);
+
+ if (f->buf_index >= IO_BUF_SIZE || f->iovcnt >= MAX_IOV_SIZE) {
qemu_fflush(f);
}
}