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Store the data to send also in iovec

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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>
This commit is contained in:
Orit Wasserman 2013-03-22 16:48:00 +02:00 committed by Juan Quintela
parent 7d8a30bb98
commit b3ea2bdb79
1 changed files with 22 additions and 2 deletions
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24
savevm.c
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@ -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);
}
}