mirror of
https://github.com/qemu/qemu.git
synced 2025-10-31 04:06:46 +00:00
5c0919d020
Since Linux switched to blk-mq as the default in Linux commit
5c279bd9e406 ("scsi: default to scsi-mq"), virtio-scsi LUNs consume
about 10x as much guest kernel memory.
This commit allows you to choose the virtqueue size for each
virtio-scsi-pci controller like this:
-device virtio-scsi-pci,id=scsi,virtqueue_size=16
The default is still 128 as before. Using smaller virtqueue_size
allows many more disks to be added to small memory virtual machines.
For a 1 vCPU, 500 MB, no swap VM I observed:
With scsi-mq enabled (upstream kernel): 175 disks
-"- ditto -"- virtqueue_size=64: 318 disks
-"- ditto -"- virtqueue_size=16: 775 disks
With scsi-mq disabled (kernel before 5c279bd9e406): 1755 disks
Note that to have any effect, this requires a kernel patch:
https://lkml.org/lkml/2017/8/10/689
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Message-Id: <20170810165255.20865-1-rjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
162 lines
4.4 KiB
C
162 lines
4.4 KiB
C
/*
|
|
* Virtio SCSI HBA
|
|
*
|
|
* Copyright IBM, Corp. 2010
|
|
*
|
|
* Authors:
|
|
* Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
|
|
*
|
|
* This work is licensed under the terms of the GNU GPL, version 2. See
|
|
* the COPYING file in the top-level directory.
|
|
*
|
|
*/
|
|
|
|
#ifndef QEMU_VIRTIO_SCSI_H
|
|
#define QEMU_VIRTIO_SCSI_H
|
|
|
|
/* Override CDB/sense data size: they are dynamic (guest controlled) in QEMU */
|
|
#define VIRTIO_SCSI_CDB_SIZE 0
|
|
#define VIRTIO_SCSI_SENSE_SIZE 0
|
|
#include "standard-headers/linux/virtio_scsi.h"
|
|
#include "hw/virtio/virtio.h"
|
|
#include "hw/pci/pci.h"
|
|
#include "hw/scsi/scsi.h"
|
|
#include "chardev/char-fe.h"
|
|
#include "sysemu/iothread.h"
|
|
|
|
#define TYPE_VIRTIO_SCSI_COMMON "virtio-scsi-common"
|
|
#define VIRTIO_SCSI_COMMON(obj) \
|
|
OBJECT_CHECK(VirtIOSCSICommon, (obj), TYPE_VIRTIO_SCSI_COMMON)
|
|
|
|
#define TYPE_VIRTIO_SCSI "virtio-scsi-device"
|
|
#define VIRTIO_SCSI(obj) \
|
|
OBJECT_CHECK(VirtIOSCSI, (obj), TYPE_VIRTIO_SCSI)
|
|
|
|
#define VIRTIO_SCSI_MAX_CHANNEL 0
|
|
#define VIRTIO_SCSI_MAX_TARGET 255
|
|
#define VIRTIO_SCSI_MAX_LUN 16383
|
|
|
|
typedef struct virtio_scsi_cmd_req VirtIOSCSICmdReq;
|
|
typedef struct virtio_scsi_cmd_resp VirtIOSCSICmdResp;
|
|
typedef struct virtio_scsi_ctrl_tmf_req VirtIOSCSICtrlTMFReq;
|
|
typedef struct virtio_scsi_ctrl_tmf_resp VirtIOSCSICtrlTMFResp;
|
|
typedef struct virtio_scsi_ctrl_an_req VirtIOSCSICtrlANReq;
|
|
typedef struct virtio_scsi_ctrl_an_resp VirtIOSCSICtrlANResp;
|
|
typedef struct virtio_scsi_event VirtIOSCSIEvent;
|
|
typedef struct virtio_scsi_config VirtIOSCSIConfig;
|
|
|
|
struct VirtIOSCSIConf {
|
|
uint32_t num_queues;
|
|
uint32_t virtqueue_size;
|
|
uint32_t max_sectors;
|
|
uint32_t cmd_per_lun;
|
|
#ifdef CONFIG_VHOST_SCSI
|
|
char *vhostfd;
|
|
char *wwpn;
|
|
#endif
|
|
CharBackend chardev;
|
|
uint32_t boot_tpgt;
|
|
IOThread *iothread;
|
|
};
|
|
|
|
struct VirtIOSCSI;
|
|
|
|
typedef struct VirtIOSCSICommon {
|
|
VirtIODevice parent_obj;
|
|
VirtIOSCSIConf conf;
|
|
|
|
uint32_t sense_size;
|
|
uint32_t cdb_size;
|
|
VirtQueue *ctrl_vq;
|
|
VirtQueue *event_vq;
|
|
VirtQueue **cmd_vqs;
|
|
} VirtIOSCSICommon;
|
|
|
|
typedef struct VirtIOSCSI {
|
|
VirtIOSCSICommon parent_obj;
|
|
|
|
SCSIBus bus;
|
|
int resetting;
|
|
bool events_dropped;
|
|
|
|
/* Fields for dataplane below */
|
|
AioContext *ctx; /* one iothread per virtio-scsi-pci for now */
|
|
|
|
bool dataplane_started;
|
|
bool dataplane_starting;
|
|
bool dataplane_stopping;
|
|
bool dataplane_fenced;
|
|
uint32_t host_features;
|
|
} VirtIOSCSI;
|
|
|
|
typedef struct VirtIOSCSIReq {
|
|
/* Note:
|
|
* - fields up to resp_iov are initialized by virtio_scsi_init_req;
|
|
* - fields starting at vring are zeroed by virtio_scsi_init_req.
|
|
* */
|
|
VirtQueueElement elem;
|
|
|
|
VirtIOSCSI *dev;
|
|
VirtQueue *vq;
|
|
QEMUSGList qsgl;
|
|
QEMUIOVector resp_iov;
|
|
|
|
union {
|
|
/* Used for two-stage request submission */
|
|
QTAILQ_ENTRY(VirtIOSCSIReq) next;
|
|
|
|
/* Used for cancellation of request during TMFs */
|
|
int remaining;
|
|
};
|
|
|
|
SCSIRequest *sreq;
|
|
size_t resp_size;
|
|
enum SCSIXferMode mode;
|
|
union {
|
|
VirtIOSCSICmdResp cmd;
|
|
VirtIOSCSICtrlTMFResp tmf;
|
|
VirtIOSCSICtrlANResp an;
|
|
VirtIOSCSIEvent event;
|
|
} resp;
|
|
union {
|
|
VirtIOSCSICmdReq cmd;
|
|
VirtIOSCSICtrlTMFReq tmf;
|
|
VirtIOSCSICtrlANReq an;
|
|
} req;
|
|
} VirtIOSCSIReq;
|
|
|
|
static inline void virtio_scsi_acquire(VirtIOSCSI *s)
|
|
{
|
|
if (s->ctx) {
|
|
aio_context_acquire(s->ctx);
|
|
}
|
|
}
|
|
|
|
static inline void virtio_scsi_release(VirtIOSCSI *s)
|
|
{
|
|
if (s->ctx) {
|
|
aio_context_release(s->ctx);
|
|
}
|
|
}
|
|
|
|
void virtio_scsi_common_realize(DeviceState *dev,
|
|
VirtIOHandleOutput ctrl,
|
|
VirtIOHandleOutput evt,
|
|
VirtIOHandleOutput cmd,
|
|
Error **errp);
|
|
|
|
void virtio_scsi_common_unrealize(DeviceState *dev, Error **errp);
|
|
bool virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq);
|
|
bool virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq);
|
|
bool virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq);
|
|
void virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq, VirtIOSCSIReq *req);
|
|
void virtio_scsi_free_req(VirtIOSCSIReq *req);
|
|
void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev,
|
|
uint32_t event, uint32_t reason);
|
|
|
|
void virtio_scsi_dataplane_setup(VirtIOSCSI *s, Error **errp);
|
|
int virtio_scsi_dataplane_start(VirtIODevice *s);
|
|
void virtio_scsi_dataplane_stop(VirtIODevice *s);
|
|
|
|
#endif /* QEMU_VIRTIO_SCSI_H */
|