| Message ID | 20170620134756.9632-4-paul.durrant@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 20/06/2017 15:47, Paul Durrant wrote: > 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.durrant@citrix.com> The QEMU block layer is not yet thread safe, but code running in IOThreads still has to take the AioContext lock. You need to call aio_context_acquire/release in blk_bh and qemu_aio_complete. Paolo > --- > Cc: Stefano Stabellini <sstabellini@kernel.org> > Cc: Anthony Perard <anthony.perard@citrix.com> > Cc: Kevin Wolf <kwolf@redhat.com> > Cc: Max Reitz <mreitz@redhat.com> > --- > hw/block/trace-events | 7 +++++++ > hw/block/xen_disk.c | 44 +++++++++++++++++++++++++++++++++++++++++++- > 2 files changed, 50 insertions(+), 1 deletion(-) > > diff --git a/hw/block/trace-events b/hw/block/trace-events > index 65e83dc258..608b24ba66 100644 > --- a/hw/block/trace-events > +++ b/hw/block/trace-events > @@ -10,3 +10,10 @@ virtio_blk_submit_multireq(void *mrb, int start, int num_reqs, uint64_t offset, > # 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 a9942d32db..ec1085c802 100644 > --- a/hw/block/xen_disk.c > +++ b/hw/block/xen_disk.c > @@ -27,10 +27,13 @@ > #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 "qom/object_interfaces.h" > +#include "trace.h" > > /* ------------------------------------------------------------- */ > > @@ -128,6 +131,9 @@ struct XenBlkDev { > DriveInfo *dinfo; > BlockBackend *blk; > QEMUBH *bh; > + > + IOThread *iothread; > + AioContext *ctx; > }; > > /* ------------------------------------------------------------- */ > @@ -923,11 +929,31 @@ static void blk_bh(void *opaque) > static void blk_alloc(struct XenDevice *xendev) > { > struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); > + Object *obj; > + char *name; > + 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); > + > + obj = object_new(TYPE_IOTHREAD); > + name = g_strdup_printf("iothread-%s", xendev->name); > + > + object_property_add_child(object_get_objects_root(), name, obj, &err); > + assert(!err); > + > + g_free(name); > + > + user_creatable_complete(obj, &err); > + assert(!err); > + > + blkdev->iothread = (IOThread *)object_dynamic_cast(obj, TYPE_IOTHREAD); > + 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; > } > @@ -954,6 +980,8 @@ 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; > @@ -1069,6 +1097,8 @@ 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; > @@ -1285,6 +1315,8 @@ 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, " > @@ -1298,13 +1330,20 @@ 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); > @@ -1338,6 +1377,8 @@ 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); > + > if (blkdev->blk || blkdev->sring) { > blk_disconnect(xendev); > } > @@ -1355,6 +1396,7 @@ static int blk_free(struct XenDevice *xendev) > g_free(blkdev->dev); > g_free(blkdev->devtype); > qemu_bh_delete(blkdev->bh); > + object_unparent(OBJECT(blkdev->iothread)); > return 0; > } > >
> -----Original Message----- > From: Paolo Bonzini [mailto:paolo.bonzini@gmail.com] On Behalf Of Paolo > Bonzini > Sent: 20 June 2017 17:08 > To: Paul Durrant <Paul.Durrant@citrix.com>; xen-devel@lists.xenproject.org; > qemu-devel@nongnu.org; qemu-block@nongnu.org > Cc: Anthony Perard <anthony.perard@citrix.com>; Kevin Wolf > <kwolf@redhat.com>; Stefano Stabellini <sstabellini@kernel.org>; Max Reitz > <mreitz@redhat.com> > Subject: Re: [PATCH 3/3] xen-disk: use an IOThread per instance > > On 20/06/2017 15:47, Paul Durrant wrote: > > 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.durrant@citrix.com> > > The QEMU block layer is not yet thread safe, but code running in > IOThreads still has to take the AioContext lock. You need to call > aio_context_acquire/release in blk_bh and qemu_aio_complete. > Ok, thanks. I'll update the patch and re-test. Cheers, Paul > Paolo > > > --- > > Cc: Stefano Stabellini <sstabellini@kernel.org> > > Cc: Anthony Perard <anthony.perard@citrix.com> > > Cc: Kevin Wolf <kwolf@redhat.com> > > Cc: Max Reitz <mreitz@redhat.com> > > --- > > hw/block/trace-events | 7 +++++++ > > hw/block/xen_disk.c | 44 > +++++++++++++++++++++++++++++++++++++++++++- > > 2 files changed, 50 insertions(+), 1 deletion(-) > > > > diff --git a/hw/block/trace-events b/hw/block/trace-events > > index 65e83dc258..608b24ba66 100644 > > --- a/hw/block/trace-events > > +++ b/hw/block/trace-events > > @@ -10,3 +10,10 @@ virtio_blk_submit_multireq(void *mrb, int start, int > num_reqs, uint64_t offset, > > # 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 a9942d32db..ec1085c802 100644 > > --- a/hw/block/xen_disk.c > > +++ b/hw/block/xen_disk.c > > @@ -27,10 +27,13 @@ > > #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 "qom/object_interfaces.h" > > +#include "trace.h" > > > > /* ------------------------------------------------------------- */ > > > > @@ -128,6 +131,9 @@ struct XenBlkDev { > > DriveInfo *dinfo; > > BlockBackend *blk; > > QEMUBH *bh; > > + > > + IOThread *iothread; > > + AioContext *ctx; > > }; > > > > /* ------------------------------------------------------------- */ > > @@ -923,11 +929,31 @@ static void blk_bh(void *opaque) > > static void blk_alloc(struct XenDevice *xendev) > > { > > struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, > xendev); > > + Object *obj; > > + char *name; > > + 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); > > + > > + obj = object_new(TYPE_IOTHREAD); > > + name = g_strdup_printf("iothread-%s", xendev->name); > > + > > + object_property_add_child(object_get_objects_root(), name, obj, > &err); > > + assert(!err); > > + > > + g_free(name); > > + > > + user_creatable_complete(obj, &err); > > + assert(!err); > > + > > + blkdev->iothread = (IOThread *)object_dynamic_cast(obj, > TYPE_IOTHREAD); > > + 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; > > } > > @@ -954,6 +980,8 @@ 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; > > @@ -1069,6 +1097,8 @@ 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; > > @@ -1285,6 +1315,8 @@ 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, " > > @@ -1298,13 +1330,20 @@ 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); > > @@ -1338,6 +1377,8 @@ 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); > > + > > if (blkdev->blk || blkdev->sring) { > > blk_disconnect(xendev); > > } > > @@ -1355,6 +1396,7 @@ static int blk_free(struct XenDevice *xendev) > > g_free(blkdev->dev); > > g_free(blkdev->devtype); > > qemu_bh_delete(blkdev->bh); > > + object_unparent(OBJECT(blkdev->iothread)); > > return 0; > > } > > > >
diff --git a/hw/block/trace-events b/hw/block/trace-events index 65e83dc258..608b24ba66 100644 --- a/hw/block/trace-events +++ b/hw/block/trace-events @@ -10,3 +10,10 @@ virtio_blk_submit_multireq(void *mrb, int start, int num_reqs, uint64_t offset, # 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 a9942d32db..ec1085c802 100644 --- a/hw/block/xen_disk.c +++ b/hw/block/xen_disk.c @@ -27,10 +27,13 @@ #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 "qom/object_interfaces.h" +#include "trace.h" /* ------------------------------------------------------------- */ @@ -128,6 +131,9 @@ struct XenBlkDev { DriveInfo *dinfo; BlockBackend *blk; QEMUBH *bh; + + IOThread *iothread; + AioContext *ctx; }; /* ------------------------------------------------------------- */ @@ -923,11 +929,31 @@ static void blk_bh(void *opaque) static void blk_alloc(struct XenDevice *xendev) { struct XenBlkDev *blkdev = container_of(xendev, struct XenBlkDev, xendev); + Object *obj; + char *name; + 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); + + obj = object_new(TYPE_IOTHREAD); + name = g_strdup_printf("iothread-%s", xendev->name); + + object_property_add_child(object_get_objects_root(), name, obj, &err); + assert(!err); + + g_free(name); + + user_creatable_complete(obj, &err); + assert(!err); + + blkdev->iothread = (IOThread *)object_dynamic_cast(obj, TYPE_IOTHREAD); + 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; } @@ -954,6 +980,8 @@ 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; @@ -1069,6 +1097,8 @@ 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; @@ -1285,6 +1315,8 @@ 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, " @@ -1298,13 +1330,20 @@ 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); @@ -1338,6 +1377,8 @@ 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); + if (blkdev->blk || blkdev->sring) { blk_disconnect(xendev); } @@ -1355,6 +1396,7 @@ static int blk_free(struct XenDevice *xendev) g_free(blkdev->dev); g_free(blkdev->devtype); qemu_bh_delete(blkdev->bh); + object_unparent(OBJECT(blkdev->iothread)); return 0; }
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.durrant@citrix.com> --- Cc: Stefano Stabellini <sstabellini@kernel.org> Cc: Anthony Perard <anthony.perard@citrix.com> Cc: Kevin Wolf <kwolf@redhat.com> Cc: Max Reitz <mreitz@redhat.com> --- hw/block/trace-events | 7 +++++++ hw/block/xen_disk.c | 44 +++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 50 insertions(+), 1 deletion(-)