This patch allocates an IOThread object for each xen_disk instance and
sets the AIO context appropriately on connect. This allows processing
of I/O to proceed in parallel.
The patch also adds tracepoints into xen_disk to make it possible to
follow the state transtions of an instance in the log.
Signed-off-by: Paul Durrant <paul.durr...@citrix.com>
---
Cc: Stefano Stabellini <sstabell...@kernel.org>
Cc: Anthony Perard <anthony.per...@citrix.com>
Cc: Kevin Wolf <kw...@redhat.com>
Cc: Max Reitz <mre...@redhat.com>
v3:
- Use new iothread_create/destroy() functions
v2:
- explicitly acquire and release AIO context in qemu_aio_complete() and
blk_bh()
---
hw/block/trace-events | 7 +++++++
hw/block/xen_disk.c | 53 ++++++++++++++++++++++++++++++++++++++++++++-------
2 files changed, 53 insertions(+), 7 deletions(-)
diff --git a/hw/block/trace-events b/hw/block/trace-events
index cb6767b3ee..962a3bfa24 100644
--- a/hw/block/trace-events
+++ b/hw/block/trace-events
@@ -10,3 +10,10 @@ virtio_blk_submit_multireq(void *vdev, void *mrb, int start,
int num_reqs, uint6
# hw/block/hd-geometry.c
hd_geometry_lchs_guess(void *blk, int cyls, int heads, int secs) "blk %p LCHS
%d %d %d"
hd_geometry_guess(void *blk, uint32_t cyls, uint32_t heads, uint32_t secs, int
trans) "blk %p CHS %u %u %u trans %d"
+
+# hw/block/xen_disk.c
+xen_disk_alloc(char *name) "%s"
+xen_disk_init(char *name) "%s"
+xen_disk_connect(char *name) "%s"
+xen_disk_disconnect(char *name) "%s"
+xen_disk_free(char *name) "%s"
diff --git a/hw/block/xen_disk.c b/hw/block/xen_disk.c
index e431bd89e8..f74fcd42d1 100644
--- a/hw/block/xen_disk.c
+++ b/hw/block/xen_disk.c
@@ -27,10 +27,12 @@
#include "hw/xen/xen_backend.h"
#include "xen_blkif.h"
#include "sysemu/blockdev.h"
+#include "sysemu/iothread.h"
#include "sysemu/block-backend.h"
#include "qapi/error.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qstring.h"
+#include "trace.h"
/* ------------------------------------------------------------- */
@@ -125,6 +127,9 @@ struct XenBlkDev {
DriveInfo *dinfo;
BlockBackend *blk;
QEMUBH *bh;
+
+ IOThread *iothread;
+ AioContext *ctx;
};
/* ------------------------------------------------------------- */
@@ -596,9 +601,12 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq);
static void qemu_aio_complete(void *opaque, int ret)
{
struct ioreq *ioreq = opaque;
+ struct XenBlkDev *blkdev = ioreq->blkdev;
+
+ aio_context_acquire(blkdev->ctx);
if (ret != 0) {
- xen_pv_printf(&ioreq->blkdev->xendev, 0, "%s I/O error\n",
+ xen_pv_printf(&blkdev->xendev, 0, "%s I/O error\n",
ioreq->req.operation == BLKIF_OP_READ ? "read" :
"write");
ioreq->aio_errors++;
}
@@ -607,10 +615,10 @@ static void qemu_aio_complete(void *opaque, int ret)
if (ioreq->presync) {
ioreq->presync = 0;
ioreq_runio_qemu_aio(ioreq);
- return;
+ goto done;
}
if (ioreq->aio_inflight > 0) {
- return;
+ goto done;
}
if (xen_feature_grant_copy) {
@@ -647,16 +655,19 @@ static void qemu_aio_complete(void *opaque, int ret)
}
case BLKIF_OP_READ:
if (ioreq->status == BLKIF_RSP_OKAY) {
- block_acct_done(blk_get_stats(ioreq->blkdev->blk), &ioreq->acct);
+ block_acct_done(blk_get_stats(blkdev->blk), &ioreq->acct);
} else {
- block_acct_failed(blk_get_stats(ioreq->blkdev->blk), &ioreq->acct);
+ block_acct_failed(blk_get_stats(blkdev->blk), &ioreq->acct);
}
break;
case BLKIF_OP_DISCARD:
default:
break;
}
- qemu_bh_schedule(ioreq->blkdev->bh);
+ qemu_bh_schedule(blkdev->bh);
+
+done:
+ aio_context_release(blkdev->ctx);
}
static bool blk_split_discard(struct ioreq *ioreq, blkif_sector_t
sector_number,
@@ -913,17 +924,29 @@ static void blk_handle_requests(struct XenBlkDev *blkdev)
static void blk_bh(void *opaque)
{
struct XenBlkDev *blkdev = opaque;
+
+ aio_context_acquire(blkdev->ctx);
blk_handle_requests(blkdev);
+ aio_context_release(blkdev->ctx);
}
static void blk_alloc(struct XenDevice *xendev)
{
struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+ Error *err = NULL;
+
+ trace_xen_disk_alloc(xendev->name);
QLIST_INIT(&blkdev->inflight);
QLIST_INIT(&blkdev->finished);
QLIST_INIT(&blkdev->freelist);
- blkdev->bh = qemu_bh_new(blk_bh, blkdev);
+
+ blkdev->iothread = iothread_create(xendev->name, &err);
+ assert(!err);
+
+ blkdev->ctx = iothread_get_aio_context(blkdev->iothread);
+ blkdev->bh = aio_bh_new(blkdev->ctx, blk_bh, blkdev);
+
if (xen_mode != XEN_EMULATE) {
batch_maps = 1;
}
@@ -950,6 +973,8 @@ static int blk_init(struct XenDevice *xendev)
int info = 0;
char *directiosafe = NULL;
+ trace_xen_disk_init(xendev->name);
+
/* read xenstore entries */
if (blkdev->params == NULL) {
char *h = NULL;
@@ -1062,6 +1087,8 @@ static int blk_connect(struct XenDevice *xendev)
unsigned int i;
uint32_t *domids;
+ trace_xen_disk_connect(xendev->name);
+
/* read-only ? */
if (blkdev->directiosafe) {
qflags = BDRV_O_NOCACHE | BDRV_O_NATIVE_AIO;
@@ -1287,6 +1314,8 @@ static int blk_connect(struct XenDevice *xendev)
blkdev->persistent_gnt_count = 0;
}
+ blk_set_aio_context(blkdev->blk, blkdev->ctx);
+
xen_be_bind_evtchn(&blkdev->xendev);
xen_pv_printf(&blkdev->xendev, 1, "ok: proto %s, nr-ring-ref %u, "
@@ -1300,13 +1329,20 @@ static void blk_disconnect(struct XenDevice *xendev)
{
struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
+ trace_xen_disk_disconnect(xendev->name);
+
+ aio_context_acquire(blkdev->ctx);
+
if (blkdev->blk) {
+ blk_set_aio_context(blkdev->blk, qemu_get_aio_context());
blk_detach_dev(blkdev->blk, blkdev);
blk_unref(blkdev->blk);
blkdev->blk = NULL;
}
xen_pv_unbind_evtchn(&blkdev->xendev);
+ aio_context_release(blkdev->ctx);
+
if (blkdev->sring) {
xengnttab_unmap(blkdev->xendev.gnttabdev, blkdev->sring,
blkdev->nr_ring_ref);
@@ -1345,6 +1381,8 @@ static int blk_free(struct XenDevice *xendev)
struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev);
struct ioreq *ioreq;
+ trace_xen_disk_free(xendev->name);
+
blk_disconnect(xendev);
while (!QLIST_EMPTY(&blkdev->freelist)) {
@@ -1360,6 +1398,7 @@ static int blk_free(struct XenDevice *xendev)
g_free(blkdev->dev);
g_free(blkdev->devtype);
qemu_bh_delete(blkdev->bh);
+ iothread_destroy(blkdev->iothread);
return 0;
}
--
2.11.0
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