xemu/hw/9pfs/virtio-9p.h
Paolo Bonzini 51b19ebe43 virtio: move allocation to virtqueue_pop/vring_pop
The return code of virtqueue_pop/vring_pop is unused except to check for
errors or 0.  We can thus easily move allocation inside the functions
and just return a pointer to the VirtQueueElement.

The advantage is that we will be able to allocate only the space that
is needed for the actual size of the s/g list instead of the full
VIRTQUEUE_MAX_SIZE items.  Currently VirtQueueElement takes about 48K
of memory, and this kind of allocation puts a lot of stress on malloc.
By cutting the size by two or three orders of magnitude, malloc can
use much more efficient algorithms.

The patch is pretty large, but changes to each device are testable
more or less independently.  Splitting it would mostly add churn.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
2016-02-06 20:39:07 +02:00

32 lines
914 B
C

#ifndef _QEMU_VIRTIO_9P_H
#define _QEMU_VIRTIO_9P_H
#include "standard-headers/linux/virtio_9p.h"
#include "hw/virtio/virtio.h"
#include "9p.h"
typedef struct V9fsVirtioState
{
VirtIODevice parent_obj;
VirtQueue *vq;
size_t config_size;
V9fsPDU pdus[MAX_REQ];
VirtQueueElement *elems[MAX_REQ];
V9fsState state;
} V9fsVirtioState;
extern void virtio_9p_push_and_notify(V9fsPDU *pdu);
ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
const char *fmt, va_list ap);
ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
const char *fmt, va_list ap);
void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
unsigned int *pniov, bool is_write);
#define TYPE_VIRTIO_9P "virtio-9p-device"
#define VIRTIO_9P(obj) \
OBJECT_CHECK(V9fsVirtioState, (obj), TYPE_VIRTIO_9P)
#endif