Author: mav
Date: Sun Mar 15 14:57:11 2015
New Revision: 280037
URL: https://svnweb.freebsd.org/changeset/base/280037
Log:
Rewrite virtio block device driver to work asynchronously and use the block
I/O interface.
Asynchronous operation, based on r280026 change, allows to not block virtual
CPU during I/O processing, that on slow/busy storage can take seconds.
Use of recently improved block I/O interface allows to process multiple
requests same time, that improves random I/O performance on wide storages.
Benchmarks of virtual disk, backed by ZVOL on RAID10 pool of 4 HDDs, show
~3.5 times random read performance improvements, while no degradation on
linear I/O. Guest CPU usage during test dropped from 100% to almost zero.
MFC after: 2 weeks
Modified:
head/usr.sbin/bhyve/block_if.c
head/usr.sbin/bhyve/pci_virtio_block.c
Modified: head/usr.sbin/bhyve/block_if.c
==============================================================================
--- head/usr.sbin/bhyve/block_if.c Sun Mar 15 14:41:26 2015
(r280036)
+++ head/usr.sbin/bhyve/block_if.c Sun Mar 15 14:57:11 2015
(r280037)
@@ -54,7 +54,7 @@ __FBSDID("$FreeBSD$");
#define BLOCKIF_SIG 0xb109b109
-#define BLOCKIF_MAXREQ 33
+#define BLOCKIF_MAXREQ 64
#define BLOCKIF_NUMTHR 8
enum blockop {
Modified: head/usr.sbin/bhyve/pci_virtio_block.c
==============================================================================
--- head/usr.sbin/bhyve/pci_virtio_block.c Sun Mar 15 14:41:26 2015
(r280036)
+++ head/usr.sbin/bhyve/pci_virtio_block.c Sun Mar 15 14:57:11 2015
(r280037)
@@ -51,6 +51,7 @@ __FBSDID("$FreeBSD$");
#include "bhyverun.h"
#include "pci_emul.h"
#include "virtio.h"
+#include "block_if.h"
#define VTBLK_RINGSZ 64
@@ -120,6 +121,13 @@ static int pci_vtblk_debug;
#define DPRINTF(params) if (pci_vtblk_debug) printf params
#define WPRINTF(params) printf params
+struct pci_vtblk_ioreq {
+ struct blockif_req io_req;
+ struct pci_vtblk_softc *io_sc;
+ uint8_t *io_status;
+ uint16_t io_idx;
+};
+
/*
* Per-device softc
*/
@@ -127,10 +135,10 @@ struct pci_vtblk_softc {
struct virtio_softc vbsc_vs;
pthread_mutex_t vsc_mtx;
struct vqueue_info vbsc_vq;
- int vbsc_fd;
- int vbsc_ischr;
- struct vtblk_config vbsc_cfg;
+ struct vtblk_config vbsc_cfg;
+ struct blockif_ctxt *bc;
char vbsc_ident[VTBLK_BLK_ID_BYTES];
+ struct pci_vtblk_ioreq vbsc_ios[VTBLK_RINGSZ];
};
static void pci_vtblk_reset(void *);
@@ -160,10 +168,34 @@ pci_vtblk_reset(void *vsc)
}
static void
+pci_vtblk_done(struct blockif_req *br, int err)
+{
+ struct pci_vtblk_ioreq *io = br->br_param;
+ struct pci_vtblk_softc *sc = io->io_sc;
+
+ /* convert errno into a virtio block error return */
+ if (err == EOPNOTSUPP || err == ENOSYS)
+ *io->io_status = VTBLK_S_UNSUPP;
+ else if (err != 0)
+ *io->io_status = VTBLK_S_IOERR;
+ else
+ *io->io_status = VTBLK_S_OK;
+
+ /*
+ * Return the descriptor back to the host.
+ * We wrote 1 byte (our status) to host.
+ */
+ pthread_mutex_lock(&sc->vsc_mtx);
+ vq_relchain(&sc->vbsc_vq, io->io_idx, 1);
+ vq_endchains(&sc->vbsc_vq, 0);
+ pthread_mutex_unlock(&sc->vsc_mtx);
+}
+
+static void
pci_vtblk_proc(struct pci_vtblk_softc *sc, struct vqueue_info *vq)
{
struct virtio_blk_hdr *vbh;
- uint8_t *status;
+ struct pci_vtblk_ioreq *io;
int i, n;
int err;
int iolen;
@@ -184,11 +216,14 @@ pci_vtblk_proc(struct pci_vtblk_softc *s
*/
assert(n >= 2 && n <= VTBLK_MAXSEGS + 2);
+ io = &sc->vbsc_ios[idx];
assert((flags[0] & VRING_DESC_F_WRITE) == 0);
assert(iov[0].iov_len == sizeof(struct virtio_blk_hdr));
vbh = iov[0].iov_base;
-
- status = iov[--n].iov_base;
+ memcpy(&io->io_req.br_iov, &iov[1], sizeof(struct iovec) * (n - 2));
+ io->io_req.br_iovcnt = n - 2;
+ io->io_req.br_offset = vbh->vbh_sector * DEV_BSIZE;
+ io->io_status = iov[--n].iov_base;
assert(iov[n].iov_len == 1);
assert(flags[n] & VRING_DESC_F_WRITE);
@@ -200,8 +235,6 @@ pci_vtblk_proc(struct pci_vtblk_softc *s
type = vbh->vbh_type & ~VBH_FLAG_BARRIER;
writeop = (type == VBH_OP_WRITE);
- offset = vbh->vbh_sector * DEV_BSIZE;
-
iolen = 0;
for (i = 1; i < n; i++) {
/*
@@ -217,48 +250,28 @@ pci_vtblk_proc(struct pci_vtblk_softc *s
DPRINTF(("virtio-block: %s op, %d bytes, %d segs, offset %ld\n\r",
writeop ? "write" : "read/ident", iolen, i - 1, offset));
- err = 0;
switch (type) {
+ case VBH_OP_READ:
+ err = blockif_read(sc->bc, &io->io_req);
+ break;
case VBH_OP_WRITE:
- if (pwritev(sc->vbsc_fd, iov + 1, i - 1, offset) < 0)
- err = errno;
+ err = blockif_write(sc->bc, &io->io_req);
break;
- case VBH_OP_READ:
- if (preadv(sc->vbsc_fd, iov + 1, i - 1, offset) < 0)
- err = errno;
+ case VBH_OP_FLUSH:
+ case VBH_OP_FLUSH_OUT:
+ err = blockif_flush(sc->bc, &io->io_req);
break;
case VBH_OP_IDENT:
/* Assume a single buffer */
strlcpy(iov[1].iov_base, sc->vbsc_ident,
MIN(iov[1].iov_len, sizeof(sc->vbsc_ident)));
- err = 0;
- break;
- case VBH_OP_FLUSH:
- case VBH_OP_FLUSH_OUT:
- if (sc->vbsc_ischr) {
- if (ioctl(sc->vbsc_fd, DIOCGFLUSH))
- err = errno;
- } else if (fsync(sc->vbsc_fd))
- err = errno;
- break;
+ pci_vtblk_done(&io->io_req, 0);
+ return;
default:
- err = -ENOSYS;
- break;
+ pci_vtblk_done(&io->io_req, EOPNOTSUPP);
+ return;
}
-
- /* convert errno into a virtio block error return */
- if (err == -ENOSYS)
- *status = VTBLK_S_UNSUPP;
- else if (err != 0)
- *status = VTBLK_S_IOERR;
- else
- *status = VTBLK_S_OK;
-
- /*
- * Return the descriptor back to the host.
- * We wrote 1 byte (our status) to host.
- */
- vq_relchain(vq, idx, 1);
+ assert(err == 0);
}
static void
@@ -268,19 +281,18 @@ pci_vtblk_notify(void *vsc, struct vqueu
while (vq_has_descs(vq))
pci_vtblk_proc(sc, vq);
- vq_endchains(vq, 1); /* Generate interrupt if appropriate. */
}
static int
pci_vtblk_init(struct vmctx *ctx, struct pci_devinst *pi, char *opts)
{
- struct stat sbuf;
+ char bident[sizeof("XX:X:X")];
+ struct blockif_ctxt *bctxt;
MD5_CTX mdctx;
u_char digest[16];
struct pci_vtblk_softc *sc;
- off_t size, sts, sto;
- int fd;
- int sectsz;
+ off_t size;
+ int i, sectsz, sts, sto;
if (opts == NULL) {
printf("virtio-block: backing device required\n");
@@ -290,43 +302,26 @@ pci_vtblk_init(struct vmctx *ctx, struct
/*
* The supplied backing file has to exist
*/
- fd = open(opts, O_RDWR);
- if (fd < 0) {
+ snprintf(bident, sizeof(bident), "%d:%d", pi->pi_slot, pi->pi_func);
+ bctxt = blockif_open(opts, bident);
+ if (bctxt == NULL) {
perror("Could not open backing file");
return (1);
}
- if (fstat(fd, &sbuf) < 0) {
- perror("Could not stat backing file");
- close(fd);
- return (1);
- }
-
- /*
- * Deal with raw devices
- */
- size = sbuf.st_size;
- sectsz = DEV_BSIZE;
- sts = sto = 0;
- if (S_ISCHR(sbuf.st_mode)) {
- if (ioctl(fd, DIOCGMEDIASIZE, &size) < 0 ||
- ioctl(fd, DIOCGSECTORSIZE, §sz)) {
- perror("Could not fetch dev blk/sector size");
- close(fd);
- return (1);
- }
- assert(size != 0);
- assert(sectsz != 0);
- if (ioctl(fd, DIOCGSTRIPESIZE, &sts) == 0 && sts > 0)
- ioctl(fd, DIOCGSTRIPEOFFSET, &sto);
- } else
- sts = sbuf.st_blksize;
+ size = blockif_size(bctxt);
+ sectsz = blockif_sectsz(bctxt);
+ blockif_psectsz(bctxt, &sts, &sto);
sc = calloc(1, sizeof(struct pci_vtblk_softc));
-
- /* record fd of storage device/file */
- sc->vbsc_fd = fd;
- sc->vbsc_ischr = S_ISCHR(sbuf.st_mode);
+ sc->bc = bctxt;
+ for (i = 0; i < VTBLK_RINGSZ; i++) {
+ struct pci_vtblk_ioreq *io = &sc->vbsc_ios[i];
+ io->io_req.br_callback = pci_vtblk_done;
+ io->io_req.br_param = io;
+ io->io_sc = sc;
+ io->io_idx = i;
+ }
pthread_mutex_init(&sc->vsc_mtx, NULL);
@@ -375,8 +370,11 @@ pci_vtblk_init(struct vmctx *ctx, struct
pci_lintr_request(pi);
- if (vi_intr_init(&sc->vbsc_vs, 1, fbsdrun_virtio_msix()))
+ if (vi_intr_init(&sc->vbsc_vs, 1, fbsdrun_virtio_msix())) {
+ blockif_close(sc->bc);
+ free(sc);
return (1);
+ }
vi_set_io_bar(&sc->vbsc_vs, 0);
return (0);
}
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