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kvm tools: Use native vectored AIO in virtio-blk

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This patch hooks AIO support into virtio-blk, allowing for faster IO.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
[ penberg@kernel.org: wrap libaio include with CONFIG_HAS_AIO ]
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This commit is contained in:
Sasha Levin
2011-11-02 07:41:14 +02:00
committed by Will Deacon
parent 1664498d4a
commit f41a132b0a
5 changed files with 88 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files
disk/core.c
+37 -2
View File
@@ -1,8 +1,32 @@
#include "kvm/disk-image.h"
#include "kvm/qcow.h"
#include "kvm/virtio-blk.h"
#include <sys/eventfd.h>
#include <sys/poll.h>
#define AIO_MAX 32
int debug_iodelay;
#ifdef CONFIG_HAS_AIO
static void *disk_image__thread(void *param)
{
struct disk_image *disk = param;
u64 dummy;
while (read(disk->evt, &dummy, sizeof(dummy)) > 0) {
struct io_event event;
struct timespec notime = {0};
while (io_getevents(disk->ctx, 1, 1, &event, &notime) > 0)
disk->disk_req_cb(event.data, event.res);
}
return NULL;
}
#endif
struct disk_image *disk_image__new(int fd, u64 size, struct disk_image_operations *ops, int use_mmap)
{
struct disk_image *disk;
@@ -26,6 +50,16 @@ struct disk_image *disk_image__new(int fd, u64 size, struct disk_image_operation
}
}
#ifdef CONFIG_HAS_AIO
if (disk) {
pthread_t thread;
disk->evt = eventfd(0, 0);
io_setup(AIO_MAX, &disk->ctx);
if (pthread_create(&thread, NULL, disk_image__thread, disk) != 0)
die("Failed starting IO thread");
}
#endif
return disk;
}
@@ -87,6 +121,7 @@ struct disk_image **disk_image__open_all(const char **filenames, bool *readonly,
goto error;
}
}
return disks;
error:
for (i = 0; i < count; i++)
@@ -151,7 +186,7 @@ ssize_t disk_image__read(struct disk_image *disk, u64 sector, const struct iovec
/* Do nothing */
}
if (disk->disk_req_cb)
if (!disk->async && disk->disk_req_cb)
disk->disk_req_cb(param, total);
return total;
@@ -183,7 +218,7 @@ ssize_t disk_image__write(struct disk_image *disk, u64 sector, const struct iove
/* Do nothing */
}
if (disk->disk_req_cb)
if (!disk->async && disk->disk_req_cb)
disk->disk_req_cb(param, total);
return total;
disk/qcow.c
+4
View File
@@ -1145,6 +1145,8 @@ static struct disk_image *qcow2_probe(int fd, bool readonly)
if (!disk_image)
goto free_refcount_table;
disk_image->async = 1;
disk_image->priv = q;
return disk_image;
@@ -1276,6 +1278,8 @@ static struct disk_image *qcow1_probe(int fd, bool readonly)
if (!disk_image)
goto free_l1_table;
disk_image->async = 1;
disk_image->priv = q;
return disk_image;
disk/raw.c
+36 -2
View File
@@ -1,11 +1,22 @@
#include "kvm/disk-image.h"
#ifdef CONFIG_HAS_AIO
#include <libaio.h>
#endif
ssize_t raw_image__read_sector(struct disk_image *disk, u64 sector, const struct iovec *iov,
int iovcount, void *param)
{
u64 offset = sector << SECTOR_SHIFT;
#ifdef CONFIG_HAS_AIO
struct iocb iocb;
return aio_preadv(disk->ctx, &iocb, disk->fd, iov, iovcount, offset,
disk->evt, param);
#else
return preadv_in_full(disk->fd, iov, iovcount, offset);
#endif
}
ssize_t raw_image__write_sector(struct disk_image *disk, u64 sector, const struct iovec *iov,
@@ -13,7 +24,14 @@ ssize_t raw_image__write_sector(struct disk_image *disk, u64 sector, const struc
{
u64 offset = sector << SECTOR_SHIFT;
#ifdef CONFIG_HAS_AIO
struct iocb iocb;
return aio_pwritev(disk->ctx, &iocb, disk->fd, iov, iovcount, offset,
disk->evt, param);
#else
return pwritev_in_full(disk->fd, iov, iovcount, offset);
#endif
}
ssize_t raw_image__read_sector_mmap(struct disk_image *disk, u64 sector, const struct iovec *iov,
@@ -59,6 +77,12 @@ int raw_image__close(struct disk_image *disk)
if (disk->priv != MAP_FAILED)
ret = munmap(disk->priv, disk->size);
close(disk->evt);
#ifdef CONFIG_HAS_VIRTIO
io_destroy(disk->ctx);
#endif
return ret;
}
@@ -83,6 +107,7 @@ struct disk_image_operations ro_ops_nowrite = {
struct disk_image *raw_image__probe(int fd, struct stat *st, bool readonly)
{
struct disk_image *disk;
if (readonly) {
/*
@@ -94,8 +119,12 @@ struct disk_image *raw_image__probe(int fd, struct stat *st, bool readonly)
disk = disk_image__new(fd, st->st_size, &ro_ops, DISK_IMAGE_MMAP);
if (disk == NULL) {
ro_ops = raw_image_regular_ops;
ro_ops.write_sector = NULL;
disk = disk_image__new(fd, st->st_size, &ro_ops_nowrite, DISK_IMAGE_REGULAR);
#ifdef CONFIG_HAS_VIRTIO
if (disk)
disk->async = 1;
#endif
}
return disk;
@@ -103,6 +132,11 @@ struct disk_image *raw_image__probe(int fd, struct stat *st, bool readonly)
/*
* Use read/write instead of mmap
*/
return disk_image__new(fd, st->st_size, &raw_image_regular_ops, DISK_IMAGE_REGULAR);
disk = disk_image__new(fd, st->st_size, &raw_image_regular_ops, DISK_IMAGE_REGULAR);
#ifdef CONFIG_HAS_VIRTIO
if (disk)
disk->async = 1;
#endif
return disk;
}
}
include/kvm/disk-image.h
+5
View File
@@ -46,6 +46,11 @@ struct disk_image {
void *priv;
void *disk_req_cb_param;
void (*disk_req_cb)(void *param, long len);
bool async;
int evt;
#ifdef CONFIG_HAS_AIO
io_context_t ctx;
#endif
};
struct disk_image *disk_image__open(const char *filename, bool readonly);
virtio/blk.c
+6 -10
View File
@@ -2,7 +2,6 @@
#include "kvm/virtio-pci-dev.h"
#include "kvm/disk-image.h"
#include "kvm/virtio.h"
#include "kvm/mutex.h"
#include "kvm/util.h"
#include "kvm/kvm.h"
@@ -11,23 +10,23 @@
#include "kvm/ioeventfd.h"
#include "kvm/guest_compat.h"
#include "kvm/virtio-pci.h"
#include "kvm/virtio.h"
#include <linux/virtio_ring.h>
#include <linux/virtio_blk.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/types.h>
#include <pthread.h>
#define VIRTIO_BLK_MAX_DEV 4
#define NUM_VIRT_QUEUES 1
#define VIRTIO_BLK_QUEUE_SIZE 128
/*
* the header and status consume too entries
*/
#define DISK_SEG_MAX (VIRTIO_BLK_QUEUE_SIZE - 2)
#define VIRTIO_BLK_QUEUE_SIZE 128
#define NUM_VIRT_QUEUES 1
struct blk_dev_req {
struct list_head list;
@@ -86,8 +85,8 @@ void virtio_blk_complete(void *param, long len)
u8 *status;
/* status */
status = req->iov[req->out + req->in - 1].iov_base;
*status = (len < 0) ? VIRTIO_BLK_S_IOERR : VIRTIO_BLK_S_OK;
status = req->iov[req->out + req->in - 1].iov_base;
*status = (len < 0) ? VIRTIO_BLK_S_IOERR : VIRTIO_BLK_S_OK;
mutex_lock(&bdev->mutex);
virt_queue__set_used_elem(req->vq, req->head, len);
@@ -103,17 +102,14 @@ static void virtio_blk_do_io_request(struct kvm *kvm, struct blk_dev_req *req)
struct virtio_blk_outhdr *req_hdr;
ssize_t block_cnt;
struct blk_dev *bdev;
struct virt_queue *queue;
struct iovec *iov;
u16 out, in, head;
u16 out, in;
block_cnt = -1;
bdev = req->bdev;
queue = req->vq;
iov = req->iov;
out = req->out;
in = req->in;
head = req->head;
req_hdr = iov[0].iov_base;
switch (req_hdr->type) {