* [PATCH v2 0/2] ublk: honor rq_affinity on request completion @ 2026-10-06 19:03 Yoav Cohen 2026-10-06 19:03 ` [PATCH v2 1/2] " Yoav Cohen 2026-10-06 19:03 ` [PATCH v2 2/2] selftests: ublk: add rq_affinity test Yoav Cohen 0 siblings, 2 replies; 7+ messages in thread From: Yoav Cohen @ 2026-10-06 19:03 UTC (permalink / raw) To: Ming Lei, Jens Axboe, linux-block, csander; +Cc: jholzman, omril, Yoav Cohen ublk ends successfully completed requests inline on the server thread, so rq_affinity never redirects completion work back to the submitting CPU the way it does for NVMe, SCSI, virtio-blk, loop, nbd and rnbd. Patch 1 fixes that and adds a feature flag so servers can detect support. Patch 2 adds a selftest for it. v2, addressing Ming Lei's review of v1: - v1 only redirected the classic-copy-mode successful-read completion; every write, flush/discard, error, and zero-copy/user-copy/ auto-buf-reg/shmem-zc I/O still completed inline as before, so rq_affinity had no effect for most traffic. ublk_end_rq() now re-derives which completion path __ublk_complete_rq() took from @req/@io state, so every outcome goes through blk_mq_complete_request_remote(). - v1 ran the new completion path unconditionally on any patched kernel. v2 adds UBLK_F_SUPPORT_RQ_AFFINITY, which a server must request at ADD_DEV time; without it, behavior is unchanged. With an SPDK-style polling user-space block server at queue depth 96, rq_affinity=2 gives 7-8% higher IOPS than today's always-inline completion by offloading a saturated server CPU; rq_affinity=0 keeps the old behavior for anyone who wants to opt out. Yoav Cohen (2): ublk: honor rq_affinity on request completion selftests: ublk: add rq_affinity test drivers/block/ublk_drv.c | 98 ++++++++++++++----- include/uapi/linux/ublk_cmd.h | 8 ++ tools/testing/selftests/ublk/Makefile | 1 + tools/testing/selftests/ublk/kublk.c | 6 +- .../testing/selftests/ublk/test_generic_18.sh | 42 ++++++++ 5 files changed, 132 insertions(+), 23 deletions(-) create mode 100755 tools/testing/selftests/ublk/test_generic_18.sh -- 2.50.1 (Apple Git-155) ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2 1/2] ublk: honor rq_affinity on request completion 2026-10-06 19:03 [PATCH v2 0/2] ublk: honor rq_affinity on request completion Yoav Cohen @ 2026-10-06 19:03 ` Yoav Cohen 2026-10-06 21:53 ` Caleb Sander Mateos 2026-10-09 14:04 ` Ming Lei 2026-10-06 19:03 ` [PATCH v2 2/2] selftests: ublk: add rq_affinity test Yoav Cohen 1 sibling, 2 replies; 7+ messages in thread From: Yoav Cohen @ 2026-10-06 19:03 UTC (permalink / raw) To: Ming Lei, Jens Axboe, linux-block, csander; +Cc: jholzman, omril, Yoav Cohen ublk ends successfully completed requests inline on the server thread that issued UBLK_IO_COMMIT_AND_FETCH_REQ, so rq_affinity never redirects completion back to the submitting CPU, unlike NVMe, SCSI, virtio-blk, loop, nbd and rnbd. Route completion through blk_mq_complete_request_remote(), with a new ->complete() callback, ublk_end_rq(). This covers every completion outcome -- reads, writes, flush/discard, errors, and the zero-copy/ user-copy/auto-buf-reg/shmem-zc paths that skip the copy-back step -- not just the classic-copy-mode successful-read case, since ublk_end_rq() re-derives which of those __ublk_complete_rq() took from @req and @io state rather than assuming one. Gate it behind a new UBLK_F_SUPPORT_RQ_AFFINITY flag that a server must request at ADD_DEV time; servers that don't ask for it keep today's always-local completion unchanged. Add ublk_support_rq_affinity() alongside the existing ublk_support_*() helpers, and check it before calling blk_mq_complete_request_remote() at both call sites. Signed-off-by: Yoav Cohen <yoav@nvidia.com> --- drivers/block/ublk_drv.c | 98 +++++++++++++++++++++++++++-------- include/uapi/linux/ublk_cmd.h | 8 +++ 2 files changed, 84 insertions(+), 22 deletions(-) diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c index 66eb55e7162e..b94293296b73 100644 --- a/drivers/block/ublk_drv.c +++ b/drivers/block/ublk_drv.c @@ -90,7 +90,8 @@ | UBLK_F_BATCH_IO \ | UBLK_F_NO_AUTO_PART_SCAN \ | UBLK_F_SHMEM_ZC \ - | UBLK_F_IO_DESC_SIZE) + | UBLK_F_IO_DESC_SIZE \ + | UBLK_F_SUPPORT_RQ_AFFINITY) #define UBLK_F_ALL_RECOVERY_FLAGS (UBLK_F_USER_RECOVERY \ | UBLK_F_USER_RECOVERY_REISSUE \ @@ -452,6 +453,11 @@ static inline bool ublk_support_user_copy(const struct ublk_queue *ubq) return ubq->flags & UBLK_F_USER_COPY; } +static inline bool ublk_support_rq_affinity(const struct ublk_queue *ubq) +{ + return ubq->flags & UBLK_F_SUPPORT_RQ_AFFINITY; +} + static inline bool ublk_dev_support_user_copy(const struct ublk_device *ub) { return ub->dev_info.flags & UBLK_F_USER_COPY; @@ -1468,6 +1474,14 @@ static inline bool ublk_need_unmap_req(const struct request *req) (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN); } +/* Whether __ublk_complete_rq() takes the copy-back/partial-completion path */ +static inline bool ublk_rq_need_unmap(const struct ublk_queue *ubq, + struct request *req) +{ + return ublk_need_map_io(ubq) && ublk_need_unmap_req(req) && + !ublk_iod_is_shmem_zc(ubq, req->tag); +} + static unsigned int ublk_map_io(const struct request *req, const struct ublk_io *io) { @@ -1549,13 +1563,62 @@ static void ublk_end_request(struct request *req, blk_status_t error) local_bh_enable(); } +/* + * Update @req with its result and requeue it if it was only partially + * completed. Returns true if @req was requeued, in which case the caller + * must not touch it any further. + * + * Run bio->bi_end_io() with softirqs disabled. If the final fput happens + * off this path, then that will prevent ublk's blkdev_release() from + * being called on current's task work, see fput() implementation. + * + * This matters for the caller completing @req locally on the ublk + * server's own thread: it may already be holding disk->open_mutex, e.g. + * reading the partition table from bdev_open(), and an fput() running + * inline there could deadlock on it. Preferably we would not be doing + * IO with a mutex held that is also used for release, but this + * work-around will suffice for now. A caller reached instead via + * blk_mq_complete_request_remote()'s softirq/IPI redirect never runs on + * that thread, so it isn't exposed to this hazard, but disabling + * softirqs here is harmless for it too. + */ +static inline bool ublk_update_and_requeue(struct request *req, + struct ublk_io *io) +{ + bool requeue; + + local_bh_disable(); + requeue = blk_update_request(req, BLK_STS_OK, io->res); + local_bh_enable(); + if (requeue) + blk_mq_requeue_request(req, true); + return requeue; +} + +static void ublk_end_rq(struct request *req) +{ + struct ublk_queue *ubq = req->mq_hctx->driver_data; + struct ublk_io *io = &ubq->ios[req->tag]; + + /* matches the two outcomes __ublk_complete_rq() may have redirected */ + if (io->res >= 0 && ublk_rq_need_unmap(ubq, req)) { + if (!ublk_update_and_requeue(req, io) && + likely(!blk_should_fake_timeout(req->q))) + __blk_mq_end_request(req, BLK_STS_OK); + return; + } + + ublk_end_request(req, io->res < 0 ? errno_to_blk_status(io->res) : + BLK_STS_OK); +} + /* todo: handle partial completion */ static inline void __ublk_complete_rq(struct request *req, struct ublk_io *io, bool need_map, struct io_comp_batch *iob) { + struct ublk_queue *ubq = req->mq_hctx->driver_data; unsigned int unmapped_bytes; blk_status_t res = BLK_STS_OK; - bool requeue; /* failed read IO if nothing is read */ if (!io->res && req_op(req) == REQ_OP_READ) @@ -1568,7 +1631,7 @@ static inline void __ublk_complete_rq(struct request *req, struct ublk_io *io, /* shmem zero copy: no data to unmap, pages already shared */ if (!need_map || !ublk_need_unmap_req(req) || - ublk_iod_is_shmem_zc(req->mq_hctx->driver_data, req->tag)) + ublk_iod_is_shmem_zc(ubq, req->tag)) goto exit; /* for READ request, writing data in iod->addr to rq buffers */ @@ -1582,31 +1645,18 @@ static inline void __ublk_complete_rq(struct request *req, struct ublk_io *io, if (unlikely(unmapped_bytes < io->res)) { if (unlikely(!unmapped_bytes)) { res = BLK_STS_IOERR; + io->res = -EIO; goto exit; } io->res = unmapped_bytes; } - /* - * Run bio->bi_end_io() with softirqs disabled. If the final fput - * happens off this path, then that will prevent ublk's blkdev_release() - * from being called on current's task work, see fput() implementation. - * - * Otherwise, ublk server may not provide forward progress in case of - * reading the partition table from bdev_open() with disk->open_mutex - * held, and causes dead lock as we could already be holding - * disk->open_mutex here. - * - * Preferably we would not be doing IO with a mutex held that is also - * used for release, but this work-around will suffice for now. - */ - local_bh_disable(); - requeue = blk_update_request(req, BLK_STS_OK, io->res); - local_bh_enable(); - if (requeue) - blk_mq_requeue_request(req, true); - else if (likely(!blk_should_fake_timeout(req->q))) { + if (ublk_support_rq_affinity(ubq) && blk_mq_complete_request_remote(req)) + return; + + if (!ublk_update_and_requeue(req, io) && + likely(!blk_should_fake_timeout(req->q))) { if (blk_mq_add_to_batch(req, iob, false, blk_mq_end_request_batch)) return; __blk_mq_end_request(req, BLK_STS_OK); @@ -1614,6 +1664,8 @@ static inline void __ublk_complete_rq(struct request *req, struct ublk_io *io, return; exit: + if (ublk_support_rq_affinity(ubq) && blk_mq_complete_request_remote(req)) + return; ublk_end_request(req, res); } @@ -2347,6 +2399,7 @@ static const struct blk_mq_ops ublk_mq_ops = { .queue_rqs = ublk_queue_rqs, .init_hctx = ublk_init_hctx, .timeout = ublk_timeout, + .complete = ublk_end_rq, }; static const struct blk_mq_ops ublk_batch_mq_ops = { @@ -2355,6 +2408,7 @@ static const struct blk_mq_ops ublk_batch_mq_ops = { .queue_rqs = ublk_batch_queue_rqs, .init_hctx = ublk_init_hctx, .timeout = ublk_timeout, + .complete = ublk_end_rq, }; static void ublk_queue_reinit(struct ublk_device *ub, struct ublk_queue *ubq) diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h index 33b25dd13965..47b5fba9519c 100644 --- a/include/uapi/linux/ublk_cmd.h +++ b/include/uapi/linux/ublk_cmd.h @@ -420,6 +420,14 @@ struct ublk_shmem_buf_reg { /* ublksrv_io_desc size is specified by ublksrv_ctrl_dev_info's io_desc_size */ #define UBLK_F_IO_DESC_SIZE (1ULL << 20) +/* + * Request completion honors the block device's rq_affinity setting + * (/sys/block/ublkbN/queue/rq_affinity): the submitting CPU's completion + * work can run there instead of always on the ublk server's CPU. Without + * this feature, rq_affinity has no effect on ublk devices. + */ +#define UBLK_F_SUPPORT_RQ_AFFINITY (1ULL << 21) + /* device state */ #define UBLK_S_DEV_DEAD 0 #define UBLK_S_DEV_LIVE 1 -- 2.50.1 (Apple Git-155) ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v2 1/2] ublk: honor rq_affinity on request completion 2026-10-06 19:03 ` [PATCH v2 1/2] " Yoav Cohen @ 2026-10-06 21:53 ` Caleb Sander Mateos 2026-10-09 13:43 ` Ming Lei 2026-10-09 14:04 ` Ming Lei 1 sibling, 1 reply; 7+ messages in thread From: Caleb Sander Mateos @ 2026-10-06 21:53 UTC (permalink / raw) To: Yoav Cohen; +Cc: Ming Lei, Jens Axboe, linux-block, jholzman, omril On Tue, Oct 6, 2026 at 12:04 PM Yoav Cohen <yoav@nvidia.com> wrote: > > ublk ends successfully completed requests inline on the server thread > that issued UBLK_IO_COMMIT_AND_FETCH_REQ, so rq_affinity never > redirects completion back to the submitting CPU, unlike NVMe, SCSI, > virtio-blk, loop, nbd and rnbd. > > Route completion through blk_mq_complete_request_remote(), with a new > ->complete() callback, ublk_end_rq(). This covers every completion > outcome -- reads, writes, flush/discard, errors, and the zero-copy/ > user-copy/auto-buf-reg/shmem-zc paths that skip the copy-back step -- > not just the classic-copy-mode successful-read case, since > ublk_end_rq() re-derives which of those __ublk_complete_rq() took from > @req and @io state rather than assuming one. > > Gate it behind a new UBLK_F_SUPPORT_RQ_AFFINITY flag that a server > must request at ADD_DEV time; servers that don't ask for it keep > today's always-local completion unchanged. Add ublk_support_rq_affinity() > alongside the existing ublk_support_*() helpers, and check it before > calling blk_mq_complete_request_remote() at both call sites. > > Signed-off-by: Yoav Cohen <yoav@nvidia.com> > --- > drivers/block/ublk_drv.c | 98 +++++++++++++++++++++++++++-------- > include/uapi/linux/ublk_cmd.h | 8 +++ > 2 files changed, 84 insertions(+), 22 deletions(-) > > diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c > index 66eb55e7162e..b94293296b73 100644 > --- a/drivers/block/ublk_drv.c > +++ b/drivers/block/ublk_drv.c > @@ -90,7 +90,8 @@ > | UBLK_F_BATCH_IO \ > | UBLK_F_NO_AUTO_PART_SCAN \ > | UBLK_F_SHMEM_ZC \ > - | UBLK_F_IO_DESC_SIZE) > + | UBLK_F_IO_DESC_SIZE \ > + | UBLK_F_SUPPORT_RQ_AFFINITY) > > #define UBLK_F_ALL_RECOVERY_FLAGS (UBLK_F_USER_RECOVERY \ > | UBLK_F_USER_RECOVERY_REISSUE \ > @@ -452,6 +453,11 @@ static inline bool ublk_support_user_copy(const struct ublk_queue *ubq) > return ubq->flags & UBLK_F_USER_COPY; > } > > +static inline bool ublk_support_rq_affinity(const struct ublk_queue *ubq) > +{ > + return ubq->flags & UBLK_F_SUPPORT_RQ_AFFINITY; > +} > + > static inline bool ublk_dev_support_user_copy(const struct ublk_device *ub) > { > return ub->dev_info.flags & UBLK_F_USER_COPY; > @@ -1468,6 +1474,14 @@ static inline bool ublk_need_unmap_req(const struct request *req) > (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN); > } > > +/* Whether __ublk_complete_rq() takes the copy-back/partial-completion path */ > +static inline bool ublk_rq_need_unmap(const struct ublk_queue *ubq, > + struct request *req) > +{ > + return ublk_need_map_io(ubq) && ublk_need_unmap_req(req) && > + !ublk_iod_is_shmem_zc(ubq, req->tag); > +} > + > static unsigned int ublk_map_io(const struct request *req, > const struct ublk_io *io) > { > @@ -1549,13 +1563,62 @@ static void ublk_end_request(struct request *req, blk_status_t error) > local_bh_enable(); > } > > +/* > + * Update @req with its result and requeue it if it was only partially > + * completed. Returns true if @req was requeued, in which case the caller > + * must not touch it any further. > + * > + * Run bio->bi_end_io() with softirqs disabled. If the final fput happens > + * off this path, then that will prevent ublk's blkdev_release() from > + * being called on current's task work, see fput() implementation. > + * > + * This matters for the caller completing @req locally on the ublk > + * server's own thread: it may already be holding disk->open_mutex, e.g. > + * reading the partition table from bdev_open(), and an fput() running > + * inline there could deadlock on it. Preferably we would not be doing > + * IO with a mutex held that is also used for release, but this > + * work-around will suffice for now. A caller reached instead via > + * blk_mq_complete_request_remote()'s softirq/IPI redirect never runs on > + * that thread, so it isn't exposed to this hazard, but disabling > + * softirqs here is harmless for it too. > + */ > +static inline bool ublk_update_and_requeue(struct request *req, > + struct ublk_io *io) > +{ > + bool requeue; > + > + local_bh_disable(); > + requeue = blk_update_request(req, BLK_STS_OK, io->res); > + local_bh_enable(); > + if (requeue) > + blk_mq_requeue_request(req, true); > + return requeue; > +} > + > +static void ublk_end_rq(struct request *req) > +{ > + struct ublk_queue *ubq = req->mq_hctx->driver_data; > + struct ublk_io *io = &ubq->ios[req->tag]; > + > + /* matches the two outcomes __ublk_complete_rq() may have redirected */ > + if (io->res >= 0 && ublk_rq_need_unmap(ubq, req)) { > + if (!ublk_update_and_requeue(req, io) && > + likely(!blk_should_fake_timeout(req->q))) > + __blk_mq_end_request(req, BLK_STS_OK); > + return; > + } > + > + ublk_end_request(req, io->res < 0 ? errno_to_blk_status(io->res) : > + BLK_STS_OK); > +} > + > /* todo: handle partial completion */ > static inline void __ublk_complete_rq(struct request *req, struct ublk_io *io, > bool need_map, struct io_comp_batch *iob) > { > + struct ublk_queue *ubq = req->mq_hctx->driver_data; mq_hctx->driver_data and ubq->flags are likely to both be cache misses on a ublk server thread servicing many queues. req->mq_hctx is probably a hit as it's in the same cache line as req->cmd_flags accessed just before in ublk_ch_uring_cmd_local() for the req_op(req) == REQ_OP_ZONE_APPEND check. It would be nice to avoid these additional dereferences, can we prevent queue_rq_affinity_store() from setting rq_affinity to a value other than 0 if UBLK_F_SUPPORT_RQ_AFFINITY isn't enabled? Perhaps indicated via a new BLK_FEAT_SUPPORTS_RQ_AFFINITY flag in struct queue_limits's features field? Best, Caleb > unsigned int unmapped_bytes; > blk_status_t res = BLK_STS_OK; > - bool requeue; > > /* failed read IO if nothing is read */ > if (!io->res && req_op(req) == REQ_OP_READ) > @@ -1568,7 +1631,7 @@ static inline void __ublk_complete_rq(struct request *req, struct ublk_io *io, > > /* shmem zero copy: no data to unmap, pages already shared */ > if (!need_map || !ublk_need_unmap_req(req) || > - ublk_iod_is_shmem_zc(req->mq_hctx->driver_data, req->tag)) > + ublk_iod_is_shmem_zc(ubq, req->tag)) > goto exit; > > /* for READ request, writing data in iod->addr to rq buffers */ > @@ -1582,31 +1645,18 @@ static inline void __ublk_complete_rq(struct request *req, struct ublk_io *io, > if (unlikely(unmapped_bytes < io->res)) { > if (unlikely(!unmapped_bytes)) { > res = BLK_STS_IOERR; > + io->res = -EIO; > goto exit; > } > > io->res = unmapped_bytes; > } > > - /* > - * Run bio->bi_end_io() with softirqs disabled. If the final fput > - * happens off this path, then that will prevent ublk's blkdev_release() > - * from being called on current's task work, see fput() implementation. > - * > - * Otherwise, ublk server may not provide forward progress in case of > - * reading the partition table from bdev_open() with disk->open_mutex > - * held, and causes dead lock as we could already be holding > - * disk->open_mutex here. > - * > - * Preferably we would not be doing IO with a mutex held that is also > - * used for release, but this work-around will suffice for now. > - */ > - local_bh_disable(); > - requeue = blk_update_request(req, BLK_STS_OK, io->res); > - local_bh_enable(); > - if (requeue) > - blk_mq_requeue_request(req, true); > - else if (likely(!blk_should_fake_timeout(req->q))) { > + if (ublk_support_rq_affinity(ubq) && blk_mq_complete_request_remote(req)) > + return; > + > + if (!ublk_update_and_requeue(req, io) && > + likely(!blk_should_fake_timeout(req->q))) { > if (blk_mq_add_to_batch(req, iob, false, blk_mq_end_request_batch)) > return; > __blk_mq_end_request(req, BLK_STS_OK); > @@ -1614,6 +1664,8 @@ static inline void __ublk_complete_rq(struct request *req, struct ublk_io *io, > > return; > exit: > + if (ublk_support_rq_affinity(ubq) && blk_mq_complete_request_remote(req)) > + return; > ublk_end_request(req, res); > } > > @@ -2347,6 +2399,7 @@ static const struct blk_mq_ops ublk_mq_ops = { > .queue_rqs = ublk_queue_rqs, > .init_hctx = ublk_init_hctx, > .timeout = ublk_timeout, > + .complete = ublk_end_rq, > }; > > static const struct blk_mq_ops ublk_batch_mq_ops = { > @@ -2355,6 +2408,7 @@ static const struct blk_mq_ops ublk_batch_mq_ops = { > .queue_rqs = ublk_batch_queue_rqs, > .init_hctx = ublk_init_hctx, > .timeout = ublk_timeout, > + .complete = ublk_end_rq, > }; > > static void ublk_queue_reinit(struct ublk_device *ub, struct ublk_queue *ubq) > diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h > index 33b25dd13965..47b5fba9519c 100644 > --- a/include/uapi/linux/ublk_cmd.h > +++ b/include/uapi/linux/ublk_cmd.h > @@ -420,6 +420,14 @@ struct ublk_shmem_buf_reg { > /* ublksrv_io_desc size is specified by ublksrv_ctrl_dev_info's io_desc_size */ > #define UBLK_F_IO_DESC_SIZE (1ULL << 20) > > +/* > + * Request completion honors the block device's rq_affinity setting > + * (/sys/block/ublkbN/queue/rq_affinity): the submitting CPU's completion > + * work can run there instead of always on the ublk server's CPU. Without > + * this feature, rq_affinity has no effect on ublk devices. > + */ > +#define UBLK_F_SUPPORT_RQ_AFFINITY (1ULL << 21) > + > /* device state */ > #define UBLK_S_DEV_DEAD 0 > #define UBLK_S_DEV_LIVE 1 > -- > 2.50.1 (Apple Git-155) > ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2 1/2] ublk: honor rq_affinity on request completion 2026-10-06 21:53 ` Caleb Sander Mateos @ 2026-10-09 13:43 ` Ming Lei 2026-10-09 15:25 ` Caleb Sander Mateos 0 siblings, 1 reply; 7+ messages in thread From: Ming Lei @ 2026-10-09 13:43 UTC (permalink / raw) To: Caleb Sander Mateos; +Cc: Yoav Cohen, Jens Axboe, linux-block, jholzman, omril On Tue, Oct 06, 2026 at 02:53:47PM -0700, Caleb Sander Mateos wrote: > On Tue, Oct 6, 2026 at 12:04 PM Yoav Cohen <yoav@nvidia.com> wrote: > > > > ublk ends successfully completed requests inline on the server thread > > that issued UBLK_IO_COMMIT_AND_FETCH_REQ, so rq_affinity never > > redirects completion back to the submitting CPU, unlike NVMe, SCSI, > > virtio-blk, loop, nbd and rnbd. > > > > Route completion through blk_mq_complete_request_remote(), with a new > > ->complete() callback, ublk_end_rq(). This covers every completion > > outcome -- reads, writes, flush/discard, errors, and the zero-copy/ > > user-copy/auto-buf-reg/shmem-zc paths that skip the copy-back step -- > > not just the classic-copy-mode successful-read case, since > > ublk_end_rq() re-derives which of those __ublk_complete_rq() took from > > @req and @io state rather than assuming one. > > > > Gate it behind a new UBLK_F_SUPPORT_RQ_AFFINITY flag that a server > > must request at ADD_DEV time; servers that don't ask for it keep > > today's always-local completion unchanged. Add ublk_support_rq_affinity() > > alongside the existing ublk_support_*() helpers, and check it before > > calling blk_mq_complete_request_remote() at both call sites. > > > > Signed-off-by: Yoav Cohen <yoav@nvidia.com> > > --- > > drivers/block/ublk_drv.c | 98 +++++++++++++++++++++++++++-------- > > include/uapi/linux/ublk_cmd.h | 8 +++ > > 2 files changed, 84 insertions(+), 22 deletions(-) > > > > diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c > > index 66eb55e7162e..b94293296b73 100644 > > --- a/drivers/block/ublk_drv.c > > +++ b/drivers/block/ublk_drv.c > > @@ -90,7 +90,8 @@ > > | UBLK_F_BATCH_IO \ > > | UBLK_F_NO_AUTO_PART_SCAN \ > > | UBLK_F_SHMEM_ZC \ > > - | UBLK_F_IO_DESC_SIZE) > > + | UBLK_F_IO_DESC_SIZE \ > > + | UBLK_F_SUPPORT_RQ_AFFINITY) > > > > #define UBLK_F_ALL_RECOVERY_FLAGS (UBLK_F_USER_RECOVERY \ > > | UBLK_F_USER_RECOVERY_REISSUE \ > > @@ -452,6 +453,11 @@ static inline bool ublk_support_user_copy(const struct ublk_queue *ubq) > > return ubq->flags & UBLK_F_USER_COPY; > > } > > > > +static inline bool ublk_support_rq_affinity(const struct ublk_queue *ubq) > > +{ > > + return ubq->flags & UBLK_F_SUPPORT_RQ_AFFINITY; > > +} > > + > > static inline bool ublk_dev_support_user_copy(const struct ublk_device *ub) > > { > > return ub->dev_info.flags & UBLK_F_USER_COPY; > > @@ -1468,6 +1474,14 @@ static inline bool ublk_need_unmap_req(const struct request *req) > > (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN); > > } > > > > +/* Whether __ublk_complete_rq() takes the copy-back/partial-completion path */ > > +static inline bool ublk_rq_need_unmap(const struct ublk_queue *ubq, > > + struct request *req) > > +{ > > + return ublk_need_map_io(ubq) && ublk_need_unmap_req(req) && > > + !ublk_iod_is_shmem_zc(ubq, req->tag); > > +} > > + > > static unsigned int ublk_map_io(const struct request *req, > > const struct ublk_io *io) > > { > > @@ -1549,13 +1563,62 @@ static void ublk_end_request(struct request *req, blk_status_t error) > > local_bh_enable(); > > } > > > > +/* > > + * Update @req with its result and requeue it if it was only partially > > + * completed. Returns true if @req was requeued, in which case the caller > > + * must not touch it any further. > > + * > > + * Run bio->bi_end_io() with softirqs disabled. If the final fput happens > > + * off this path, then that will prevent ublk's blkdev_release() from > > + * being called on current's task work, see fput() implementation. > > + * > > + * This matters for the caller completing @req locally on the ublk > > + * server's own thread: it may already be holding disk->open_mutex, e.g. > > + * reading the partition table from bdev_open(), and an fput() running > > + * inline there could deadlock on it. Preferably we would not be doing > > + * IO with a mutex held that is also used for release, but this > > + * work-around will suffice for now. A caller reached instead via > > + * blk_mq_complete_request_remote()'s softirq/IPI redirect never runs on > > + * that thread, so it isn't exposed to this hazard, but disabling > > + * softirqs here is harmless for it too. > > + */ > > +static inline bool ublk_update_and_requeue(struct request *req, > > + struct ublk_io *io) > > +{ > > + bool requeue; > > + > > + local_bh_disable(); > > + requeue = blk_update_request(req, BLK_STS_OK, io->res); > > + local_bh_enable(); > > + if (requeue) > > + blk_mq_requeue_request(req, true); > > + return requeue; > > +} > > + > > +static void ublk_end_rq(struct request *req) > > +{ > > + struct ublk_queue *ubq = req->mq_hctx->driver_data; > > + struct ublk_io *io = &ubq->ios[req->tag]; > > + > > + /* matches the two outcomes __ublk_complete_rq() may have redirected */ > > + if (io->res >= 0 && ublk_rq_need_unmap(ubq, req)) { > > + if (!ublk_update_and_requeue(req, io) && > > + likely(!blk_should_fake_timeout(req->q))) > > + __blk_mq_end_request(req, BLK_STS_OK); > > + return; > > + } > > + > > + ublk_end_request(req, io->res < 0 ? errno_to_blk_status(io->res) : > > + BLK_STS_OK); > > +} > > + > > /* todo: handle partial completion */ > > static inline void __ublk_complete_rq(struct request *req, struct ublk_io *io, > > bool need_map, struct io_comp_batch *iob) > > { > > + struct ublk_queue *ubq = req->mq_hctx->driver_data; > > mq_hctx->driver_data and ubq->flags are likely to both be cache misses > on a ublk server thread servicing many queues. req->mq_hctx is > probably a hit as it's in the same cache line as req->cmd_flags > accessed just before in ublk_ch_uring_cmd_local() for the req_op(req) > == REQ_OP_ZONE_APPEND check. It would be nice to avoid these > additional dereferences, can we prevent queue_rq_affinity_store() from > setting rq_affinity to a value other than 0 if > UBLK_F_SUPPORT_RQ_AFFINITY isn't enabled? Perhaps indicated via a new > BLK_FEAT_SUPPORTS_RQ_AFFINITY flag in struct queue_limits's features > field? ubq is only for ublk_support_rq_affinity(ubq), `maybe rq_affinity` can be passed by __ublk_complete_rq() parameter via ublk_dev_support_rq_affinity(ub). BTW, the one for ublk_iod_is_shmem_zc() can't be avoided. Thanks, Ming ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2 1/2] ublk: honor rq_affinity on request completion 2026-10-09 13:43 ` Ming Lei @ 2026-10-09 15:25 ` Caleb Sander Mateos 0 siblings, 0 replies; 7+ messages in thread From: Caleb Sander Mateos @ 2026-10-09 15:25 UTC (permalink / raw) To: Ming Lei; +Cc: Yoav Cohen, Jens Axboe, linux-block, jholzman, omril On Fri, Oct 9, 2026 at 6:43 AM Ming Lei <tom.leiming@gmail.com> wrote: > > On Tue, Oct 06, 2026 at 02:53:47PM -0700, Caleb Sander Mateos wrote: > > On Tue, Oct 6, 2026 at 12:04 PM Yoav Cohen <yoav@nvidia.com> wrote: > > > > > > ublk ends successfully completed requests inline on the server thread > > > that issued UBLK_IO_COMMIT_AND_FETCH_REQ, so rq_affinity never > > > redirects completion back to the submitting CPU, unlike NVMe, SCSI, > > > virtio-blk, loop, nbd and rnbd. > > > > > > Route completion through blk_mq_complete_request_remote(), with a new > > > ->complete() callback, ublk_end_rq(). This covers every completion > > > outcome -- reads, writes, flush/discard, errors, and the zero-copy/ > > > user-copy/auto-buf-reg/shmem-zc paths that skip the copy-back step -- > > > not just the classic-copy-mode successful-read case, since > > > ublk_end_rq() re-derives which of those __ublk_complete_rq() took from > > > @req and @io state rather than assuming one. > > > > > > Gate it behind a new UBLK_F_SUPPORT_RQ_AFFINITY flag that a server > > > must request at ADD_DEV time; servers that don't ask for it keep > > > today's always-local completion unchanged. Add ublk_support_rq_affinity() > > > alongside the existing ublk_support_*() helpers, and check it before > > > calling blk_mq_complete_request_remote() at both call sites. > > > > > > Signed-off-by: Yoav Cohen <yoav@nvidia.com> > > > --- > > > drivers/block/ublk_drv.c | 98 +++++++++++++++++++++++++++-------- > > > include/uapi/linux/ublk_cmd.h | 8 +++ > > > 2 files changed, 84 insertions(+), 22 deletions(-) > > > > > > diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c > > > index 66eb55e7162e..b94293296b73 100644 > > > --- a/drivers/block/ublk_drv.c > > > +++ b/drivers/block/ublk_drv.c > > > @@ -90,7 +90,8 @@ > > > | UBLK_F_BATCH_IO \ > > > | UBLK_F_NO_AUTO_PART_SCAN \ > > > | UBLK_F_SHMEM_ZC \ > > > - | UBLK_F_IO_DESC_SIZE) > > > + | UBLK_F_IO_DESC_SIZE \ > > > + | UBLK_F_SUPPORT_RQ_AFFINITY) > > > > > > #define UBLK_F_ALL_RECOVERY_FLAGS (UBLK_F_USER_RECOVERY \ > > > | UBLK_F_USER_RECOVERY_REISSUE \ > > > @@ -452,6 +453,11 @@ static inline bool ublk_support_user_copy(const struct ublk_queue *ubq) > > > return ubq->flags & UBLK_F_USER_COPY; > > > } > > > > > > +static inline bool ublk_support_rq_affinity(const struct ublk_queue *ubq) > > > +{ > > > + return ubq->flags & UBLK_F_SUPPORT_RQ_AFFINITY; > > > +} > > > + > > > static inline bool ublk_dev_support_user_copy(const struct ublk_device *ub) > > > { > > > return ub->dev_info.flags & UBLK_F_USER_COPY; > > > @@ -1468,6 +1474,14 @@ static inline bool ublk_need_unmap_req(const struct request *req) > > > (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN); > > > } > > > > > > +/* Whether __ublk_complete_rq() takes the copy-back/partial-completion path */ > > > +static inline bool ublk_rq_need_unmap(const struct ublk_queue *ubq, > > > + struct request *req) > > > +{ > > > + return ublk_need_map_io(ubq) && ublk_need_unmap_req(req) && > > > + !ublk_iod_is_shmem_zc(ubq, req->tag); > > > +} > > > + > > > static unsigned int ublk_map_io(const struct request *req, > > > const struct ublk_io *io) > > > { > > > @@ -1549,13 +1563,62 @@ static void ublk_end_request(struct request *req, blk_status_t error) > > > local_bh_enable(); > > > } > > > > > > +/* > > > + * Update @req with its result and requeue it if it was only partially > > > + * completed. Returns true if @req was requeued, in which case the caller > > > + * must not touch it any further. > > > + * > > > + * Run bio->bi_end_io() with softirqs disabled. If the final fput happens > > > + * off this path, then that will prevent ublk's blkdev_release() from > > > + * being called on current's task work, see fput() implementation. > > > + * > > > + * This matters for the caller completing @req locally on the ublk > > > + * server's own thread: it may already be holding disk->open_mutex, e.g. > > > + * reading the partition table from bdev_open(), and an fput() running > > > + * inline there could deadlock on it. Preferably we would not be doing > > > + * IO with a mutex held that is also used for release, but this > > > + * work-around will suffice for now. A caller reached instead via > > > + * blk_mq_complete_request_remote()'s softirq/IPI redirect never runs on > > > + * that thread, so it isn't exposed to this hazard, but disabling > > > + * softirqs here is harmless for it too. > > > + */ > > > +static inline bool ublk_update_and_requeue(struct request *req, > > > + struct ublk_io *io) > > > +{ > > > + bool requeue; > > > + > > > + local_bh_disable(); > > > + requeue = blk_update_request(req, BLK_STS_OK, io->res); > > > + local_bh_enable(); > > > + if (requeue) > > > + blk_mq_requeue_request(req, true); > > > + return requeue; > > > +} > > > + > > > +static void ublk_end_rq(struct request *req) > > > +{ > > > + struct ublk_queue *ubq = req->mq_hctx->driver_data; > > > + struct ublk_io *io = &ubq->ios[req->tag]; > > > + > > > + /* matches the two outcomes __ublk_complete_rq() may have redirected */ > > > + if (io->res >= 0 && ublk_rq_need_unmap(ubq, req)) { > > > + if (!ublk_update_and_requeue(req, io) && > > > + likely(!blk_should_fake_timeout(req->q))) > > > + __blk_mq_end_request(req, BLK_STS_OK); > > > + return; > > > + } > > > + > > > + ublk_end_request(req, io->res < 0 ? errno_to_blk_status(io->res) : > > > + BLK_STS_OK); > > > +} > > > + > > > /* todo: handle partial completion */ > > > static inline void __ublk_complete_rq(struct request *req, struct ublk_io *io, > > > bool need_map, struct io_comp_batch *iob) > > > { > > > + struct ublk_queue *ubq = req->mq_hctx->driver_data; > > > > mq_hctx->driver_data and ubq->flags are likely to both be cache misses > > on a ublk server thread servicing many queues. req->mq_hctx is > > probably a hit as it's in the same cache line as req->cmd_flags > > accessed just before in ublk_ch_uring_cmd_local() for the req_op(req) > > == REQ_OP_ZONE_APPEND check. It would be nice to avoid these > > additional dereferences, can we prevent queue_rq_affinity_store() from > > setting rq_affinity to a value other than 0 if > > UBLK_F_SUPPORT_RQ_AFFINITY isn't enabled? Perhaps indicated via a new > > BLK_FEAT_SUPPORTS_RQ_AFFINITY flag in struct queue_limits's features > > field? > > ubq is only for ublk_support_rq_affinity(ubq), `maybe rq_affinity` can be > passed by __ublk_complete_rq() parameter via > ublk_dev_support_rq_affinity(ub). > > BTW, the one for ublk_iod_is_shmem_zc() can't be avoided. Yes, but ublk_iod_is_shmem_zc() is only called in the need_map case. I would expect most modern ublk servers to enable user copy and/or zero copy, so they wouldn't take that path. Best, Caleb ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v2 1/2] ublk: honor rq_affinity on request completion 2026-10-06 19:03 ` [PATCH v2 1/2] " Yoav Cohen 2026-10-06 21:53 ` Caleb Sander Mateos @ 2026-10-09 14:04 ` Ming Lei 1 sibling, 0 replies; 7+ messages in thread From: Ming Lei @ 2026-10-09 14:04 UTC (permalink / raw) To: Yoav Cohen; +Cc: Jens Axboe, linux-block, csander, jholzman, omril On Tue, Oct 06, 2026 at 10:03:47PM +0300, Yoav Cohen wrote: > ublk ends successfully completed requests inline on the server thread > that issued UBLK_IO_COMMIT_AND_FETCH_REQ, so rq_affinity never > redirects completion back to the submitting CPU, unlike NVMe, SCSI, > virtio-blk, loop, nbd and rnbd. > > Route completion through blk_mq_complete_request_remote(), with a new > ->complete() callback, ublk_end_rq(). This covers every completion > outcome -- reads, writes, flush/discard, errors, and the zero-copy/ > user-copy/auto-buf-reg/shmem-zc paths that skip the copy-back step -- > not just the classic-copy-mode successful-read case, since > ublk_end_rq() re-derives which of those __ublk_complete_rq() took from > @req and @io state rather than assuming one. > > Gate it behind a new UBLK_F_SUPPORT_RQ_AFFINITY flag that a server > must request at ADD_DEV time; servers that don't ask for it keep > today's always-local completion unchanged. Add ublk_support_rq_affinity() > alongside the existing ublk_support_*() helpers, and check it before > calling blk_mq_complete_request_remote() at both call sites. > > Signed-off-by: Yoav Cohen <yoav@nvidia.com> > --- > drivers/block/ublk_drv.c | 98 +++++++++++++++++++++++++++-------- > include/uapi/linux/ublk_cmd.h | 8 +++ > 2 files changed, 84 insertions(+), 22 deletions(-) > > diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c > index 66eb55e7162e..b94293296b73 100644 > --- a/drivers/block/ublk_drv.c > +++ b/drivers/block/ublk_drv.c > @@ -90,7 +90,8 @@ > | UBLK_F_BATCH_IO \ > | UBLK_F_NO_AUTO_PART_SCAN \ > | UBLK_F_SHMEM_ZC \ > - | UBLK_F_IO_DESC_SIZE) > + | UBLK_F_IO_DESC_SIZE \ > + | UBLK_F_SUPPORT_RQ_AFFINITY) > > #define UBLK_F_ALL_RECOVERY_FLAGS (UBLK_F_USER_RECOVERY \ > | UBLK_F_USER_RECOVERY_REISSUE \ > @@ -452,6 +453,11 @@ static inline bool ublk_support_user_copy(const struct ublk_queue *ubq) > return ubq->flags & UBLK_F_USER_COPY; > } > > +static inline bool ublk_support_rq_affinity(const struct ublk_queue *ubq) > +{ > + return ubq->flags & UBLK_F_SUPPORT_RQ_AFFINITY; > +} > + > static inline bool ublk_dev_support_user_copy(const struct ublk_device *ub) > { > return ub->dev_info.flags & UBLK_F_USER_COPY; > @@ -1468,6 +1474,14 @@ static inline bool ublk_need_unmap_req(const struct request *req) > (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN); > } > > +/* Whether __ublk_complete_rq() takes the copy-back/partial-completion path */ > +static inline bool ublk_rq_need_unmap(const struct ublk_queue *ubq, > + struct request *req) > +{ > + return ublk_need_map_io(ubq) && ublk_need_unmap_req(req) && > + !ublk_iod_is_shmem_zc(ubq, req->tag); > +} > + > static unsigned int ublk_map_io(const struct request *req, > const struct ublk_io *io) > { > @@ -1549,13 +1563,62 @@ static void ublk_end_request(struct request *req, blk_status_t error) > local_bh_enable(); > } > > +/* > + * Update @req with its result and requeue it if it was only partially > + * completed. Returns true if @req was requeued, in which case the caller > + * must not touch it any further. > + * > + * Run bio->bi_end_io() with softirqs disabled. If the final fput happens > + * off this path, then that will prevent ublk's blkdev_release() from > + * being called on current's task work, see fput() implementation. > + * > + * This matters for the caller completing @req locally on the ublk > + * server's own thread: it may already be holding disk->open_mutex, e.g. > + * reading the partition table from bdev_open(), and an fput() running > + * inline there could deadlock on it. Preferably we would not be doing > + * IO with a mutex held that is also used for release, but this > + * work-around will suffice for now. A caller reached instead via > + * blk_mq_complete_request_remote()'s softirq/IPI redirect never runs on > + * that thread, so it isn't exposed to this hazard, but disabling > + * softirqs here is harmless for it too. > + */ > +static inline bool ublk_update_and_requeue(struct request *req, > + struct ublk_io *io) > +{ > + bool requeue; > + > + local_bh_disable(); > + requeue = blk_update_request(req, BLK_STS_OK, io->res); > + local_bh_enable(); > + if (requeue) > + blk_mq_requeue_request(req, true); > + return requeue; > +} > + > +static void ublk_end_rq(struct request *req) > +{ > + struct ublk_queue *ubq = req->mq_hctx->driver_data; > + struct ublk_io *io = &ubq->ios[req->tag]; > + > + /* matches the two outcomes __ublk_complete_rq() may have redirected */ > + if (io->res >= 0 && ublk_rq_need_unmap(ubq, req)) { > + if (!ublk_update_and_requeue(req, io) && > + likely(!blk_should_fake_timeout(req->q))) > + __blk_mq_end_request(req, BLK_STS_OK); > + return; > + } ublk_end_rq() may be run from remove cpu, then it becomes fragile to touch `io` here, and not efficient to touch `ubq` as Caleb mentioned. It could be simplified a lot to just deal with normal io->res == blk_rq_bytes(req) here, meantime keep everything else(short write, failure, ...) in __ublk_complete_rq(). Thanks, Ming ^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v2 2/2] selftests: ublk: add rq_affinity test 2026-10-06 19:03 [PATCH v2 0/2] ublk: honor rq_affinity on request completion Yoav Cohen 2026-10-06 19:03 ` [PATCH v2 1/2] " Yoav Cohen @ 2026-10-06 19:03 ` Yoav Cohen 1 sibling, 0 replies; 7+ messages in thread From: Yoav Cohen @ 2026-10-06 19:03 UTC (permalink / raw) To: Ming Lei, Jens Axboe, linux-block, csander; +Cc: jholzman, omril, Yoav Cohen Add UBLK_F_SUPPORT_RQ_AFFINITY to kublk's feature table and a --rq_affinity flag to request it at ADD_DEV time, and add test_generic_18.sh: writes and verifies data on a loop device with I/O pinned to one CPU while cycling rq_affinity through 0, 1 and 2. Skipped on kernels without UBLK_F_SUPPORT_RQ_AFFINITY. Signed-off-by: Yoav Cohen <yoav@nvidia.com> --- tools/testing/selftests/ublk/Makefile | 1 + tools/testing/selftests/ublk/kublk.c | 6 ++- .../testing/selftests/ublk/test_generic_18.sh | 42 +++++++++++++++++++ 3 files changed, 48 insertions(+), 1 deletion(-) create mode 100755 tools/testing/selftests/ublk/test_generic_18.sh diff --git a/tools/testing/selftests/ublk/Makefile b/tools/testing/selftests/ublk/Makefile index 37883e9d50ec..d12e9879b89a 100644 --- a/tools/testing/selftests/ublk/Makefile +++ b/tools/testing/selftests/ublk/Makefile @@ -19,6 +19,7 @@ TEST_PROGS += test_generic_12.sh TEST_PROGS += test_generic_13.sh TEST_PROGS += test_generic_16.sh TEST_PROGS += test_generic_17.sh +TEST_PROGS += test_generic_18.sh TEST_PROGS += test_batch_01.sh TEST_PROGS += test_batch_02.sh diff --git a/tools/testing/selftests/ublk/kublk.c b/tools/testing/selftests/ublk/kublk.c index 2400b4615766..e3afef0e7628 100644 --- a/tools/testing/selftests/ublk/kublk.c +++ b/tools/testing/selftests/ublk/kublk.c @@ -2083,6 +2083,7 @@ static int cmd_dev_get_features(void) FEAT_NAME(UBLK_F_NO_AUTO_PART_SCAN), FEAT_NAME(UBLK_F_SHMEM_ZC), FEAT_NAME(UBLK_F_IO_DESC_SIZE), + FEAT_NAME(UBLK_F_SUPPORT_RQ_AFFINITY), }; struct ublk_dev *dev; __u64 features = 0; @@ -2180,7 +2181,7 @@ static void __cmd_create_help(char *exe, bool recovery) printf("\t[--nthreads threads] [--per_io_tasks]\n"); printf("\t[--integrity_capable] [--integrity_reftag] [--metadata_size SIZE] " "[--pi_offset OFFSET] [--csum_type ip|t10dif|nvme] [--tag_size SIZE]\n"); - printf("\t[--batch|-b] [--rotate_auto_buf] [--no_auto_part_scan]\n"); + printf("\t[--batch|-b] [--rotate_auto_buf] [--no_auto_part_scan] [--rq_affinity]\n"); printf("\t[--io_desc_size SIZE]\n"); printf("\t[target options] [backfile1] [backfile2] ...\n"); printf("\tdefault: nr_queues=2(max 32), depth=128(max 1024), dev_id=-1(auto allocation)\n"); @@ -2260,6 +2261,7 @@ int main(int argc, char *argv[]) { "batch", 0, NULL, 'b'}, { "rotate_auto_buf", 0, NULL, 0 }, { "no_auto_part_scan", 0, NULL, 0 }, + { "rq_affinity", 0, NULL, 0 }, { "shmem_zc", 0, NULL, 0 }, { "htlb", 1, NULL, 0 }, { "rdonly_shmem_buf", 0, NULL, 0 }, @@ -2407,6 +2409,8 @@ int main(int argc, char *argv[]) ctx.safe_stop = 1; if (!strcmp(longopts[option_idx].name, "no_auto_part_scan")) ctx.flags |= UBLK_F_NO_AUTO_PART_SCAN; + if (!strcmp(longopts[option_idx].name, "rq_affinity")) + ctx.flags |= UBLK_F_SUPPORT_RQ_AFFINITY; if (!strcmp(longopts[option_idx].name, "shmem_zc")) ctx.flags |= UBLK_F_SHMEM_ZC; if (!strcmp(longopts[option_idx].name, "htlb")) diff --git a/tools/testing/selftests/ublk/test_generic_18.sh b/tools/testing/selftests/ublk/test_generic_18.sh new file mode 100755 index 000000000000..c899a5bf0364 --- /dev/null +++ b/tools/testing/selftests/ublk/test_generic_18.sh @@ -0,0 +1,42 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 + +. "$(cd "$(dirname "$0")" && pwd)"/test_common.sh + +ERR_CODE=0 + +if ! _have_program fio; then + exit "$UBLK_SKIP_CODE" +fi + +if ! _have_feature "SUPPORT_RQ_AFFINITY"; then + exit "$UBLK_SKIP_CODE" +fi + +_prep_test "loop" "write and verify I/O across rq_affinity settings" + +_create_backfile 0 256M + +dev_id=$(_add_ublk_dev -t loop --rq_affinity "${UBLK_BACKFILES[0]}") +_check_add_dev $TID $? + +rq_affinity_path=/sys/block/ublkb"${dev_id}"/queue/rq_affinity + +for affinity in 0 1 2; do + echo "${affinity}" > "${rq_affinity_path}" + + # Pin submission to a single CPU so rq_affinity has somewhere to + # redirect completion to. + taskset -c 0 fio --name=verify --rw=randwrite --direct=1 \ + --ioengine=libaio --bs=8k --iodepth=32 --verify=crc32c \ + --do_verify=1 --verify_state_save=0 \ + --filename=/dev/ublkb"${dev_id}" --size=256M > /dev/null + if [ $? -ne 0 ]; then + echo "fio verify failed with rq_affinity=${affinity}" + ERR_CODE=255 + break + fi +done + +_cleanup_test +_show_result $TID $ERR_CODE -- 2.50.1 (Apple Git-155) ^ permalink raw reply related [flat|nested] 7+ messages in thread
end of thread, other threads:[~2026-10-09 15:26 UTC | newest] Thread overview: 7+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2026-10-06 19:03 [PATCH v2 0/2] ublk: honor rq_affinity on request completion Yoav Cohen 2026-10-06 19:03 ` [PATCH v2 1/2] " Yoav Cohen 2026-10-06 21:53 ` Caleb Sander Mateos 2026-10-09 13:43 ` Ming Lei 2026-10-09 15:25 ` Caleb Sander Mateos 2026-10-09 14:04 ` Ming Lei 2026-10-06 19:03 ` [PATCH v2 2/2] selftests: ublk: add rq_affinity test Yoav Cohen
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