Linux-stable-mirror December 2017

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[Linux-stable-mirror] [PATCH 6/7] blk-mq: Rerun hardware queues after having called .put_budget()

by Bart Van Assche

During request dispatch, after a scheduler or per-CPU queue has been examined, .put_budget() is called if the examined queue is empty. Since a new request may be queued concurrently with the .put_budget() call, a request queue needs to be rerun after each .put_budget() call. Fixes: commit 1f460b63d4b3 ("blk-mq: don't restart queue when .get_budget returns BLK_STS_RESOURCE") Signed-off-by: Bart Van Assche <bart.vanassche(a)wdc.com> Cc: Ming Lei <ming.lei(a)redhat.com> Cc: Omar Sandoval <osandov(a)fb.com> Cc: Christoph Hellwig <hch(a)lst.de> Cc: Hannes Reinecke <hare(a)suse.de> Cc: Johannes Thumshirn <jthumshirn(a)suse.de> Cc: <stable(a)vger.kernel.org> --- block/blk-mq-sched.c | 39 ++++++++++++++++++++------------------- block/blk-mq-sched.h | 2 +- block/blk-mq.c | 17 ++++++++++++----- 3 files changed, 33 insertions(+), 25 deletions(-) diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index 398545d94521..3a935081a2d3 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -82,12 +82,8 @@ static bool blk_mq_sched_restart_hctx(struct blk_mq_hw_ctx *hctx) return blk_mq_run_hw_queue(hctx, true); } -/* - * Only SCSI implements .get_budget and .put_budget, and SCSI restarts - * its queue by itself in its completion handler, so we don't need to - * restart queue if .get_budget() returns BLK_STS_NO_RESOURCE. - */ -static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx) +/* returns true if hctx needs to be run again */ +static bool blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx) { struct request_queue *q = hctx->queue; struct elevator_queue *e = q->elevator; @@ -106,7 +102,7 @@ static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx) rq = e->type->ops.mq.dispatch_request(hctx); if (!rq) { blk_mq_put_dispatch_budget(hctx); - break; + return true; } /* @@ -116,6 +112,8 @@ static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx) */ list_add(&rq->queuelist, &rq_list); } while (blk_mq_dispatch_rq_list(q, &rq_list, true)); + + return false; } static struct blk_mq_ctx *blk_mq_next_ctx(struct blk_mq_hw_ctx *hctx, @@ -129,16 +127,13 @@ static struct blk_mq_ctx *blk_mq_next_ctx(struct blk_mq_hw_ctx *hctx, return hctx->ctxs[idx]; } -/* - * Only SCSI implements .get_budget and .put_budget, and SCSI restarts - * its queue by itself in its completion handler, so we don't need to - * restart queue if .get_budget() returns BLK_STS_NO_RESOURCE. - */ -static void blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx) +/* returns true if hctx needs to be run again */ +static bool blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx) { struct request_queue *q = hctx->queue; LIST_HEAD(rq_list); struct blk_mq_ctx *ctx = READ_ONCE(hctx->dispatch_from); + bool ret = false; do { struct request *rq; @@ -152,6 +147,7 @@ static void blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx) rq = blk_mq_dequeue_from_ctx(hctx, ctx); if (!rq) { blk_mq_put_dispatch_budget(hctx); + ret = true; break; } @@ -168,19 +164,22 @@ static void blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx) } while (blk_mq_dispatch_rq_list(q, &rq_list, true)); WRITE_ONCE(hctx->dispatch_from, ctx); + + return ret; } /* return true if hw queue need to be run again */ -void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) +bool blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) { struct request_queue *q = hctx->queue; struct elevator_queue *e = q->elevator; const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request; LIST_HEAD(rq_list); + bool run_queue = false; /* RCU or SRCU read lock is needed before checking quiesced flag */ if (unlikely(blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q))) - return; + return false; hctx->run++; @@ -212,12 +211,12 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) if (!list_empty(&rq_list)) { if (blk_mq_dispatch_rq_list(q, &rq_list, false)) { if (has_sched_dispatch) - blk_mq_do_dispatch_sched(hctx); + run_queue = blk_mq_do_dispatch_sched(hctx); else - blk_mq_do_dispatch_ctx(hctx); + run_queue = blk_mq_do_dispatch_ctx(hctx); } } else if (has_sched_dispatch) { - blk_mq_do_dispatch_sched(hctx); + run_queue = blk_mq_do_dispatch_sched(hctx); } else if (q->mq_ops->get_budget) { /* * If we need to get budget before queuing request, we @@ -227,11 +226,13 @@ void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) * TODO: get more budgets, and dequeue more requests in * one time. */ - blk_mq_do_dispatch_ctx(hctx); + run_queue = blk_mq_do_dispatch_ctx(hctx); } else { blk_mq_flush_busy_ctxs(hctx, &rq_list); blk_mq_dispatch_rq_list(q, &rq_list, false); } + + return run_queue; } bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio, diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h index ba1d1418a96d..1ccfb8027cfc 100644 --- a/block/blk-mq-sched.h +++ b/block/blk-mq-sched.h @@ -23,7 +23,7 @@ void blk_mq_sched_insert_requests(struct request_queue *q, struct blk_mq_ctx *ctx, struct list_head *list, bool run_queue_async); -void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx); +bool blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx); int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e); void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e); diff --git a/block/blk-mq.c b/block/blk-mq.c index 3e0ce940377f..b4225f606737 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1079,7 +1079,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, { struct blk_mq_hw_ctx *hctx; struct request *rq, *nxt; - bool no_tag = false; + bool restart = false, no_tag = false; int errors, queued; if (list_empty(list)) @@ -1105,8 +1105,10 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, * we'll re-run it below. */ if (!blk_mq_mark_tag_wait(&hctx, rq)) { - if (got_budget) + if (got_budget) { blk_mq_put_dispatch_budget(hctx); + restart = true; + } /* * For non-shared tags, the RESTART check * will suffice. @@ -1193,7 +1195,8 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq * and dm-rq. */ - if (!blk_mq_sched_needs_restart(hctx) || + if (restart || + !blk_mq_sched_needs_restart(hctx) || (no_tag && list_empty_careful(&hctx->dispatch_wait.entry))) blk_mq_run_hw_queue(hctx, true); } @@ -1204,6 +1207,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) { int srcu_idx; + bool run_queue; /* * We should be running this queue from one of the CPUs that @@ -1220,15 +1224,18 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) if (!(hctx->flags & BLK_MQ_F_BLOCKING)) { rcu_read_lock(); - blk_mq_sched_dispatch_requests(hctx); + run_queue = blk_mq_sched_dispatch_requests(hctx); rcu_read_unlock(); } else { might_sleep(); srcu_idx = srcu_read_lock(hctx->queue_rq_srcu); - blk_mq_sched_dispatch_requests(hctx); + run_queue = blk_mq_sched_dispatch_requests(hctx); srcu_read_unlock(hctx->queue_rq_srcu, srcu_idx); } + + if (run_queue) + blk_mq_sched_restart(hctx); } /* -- 2.15.0

7 years

[Linux-stable-mirror] v4.9.66 build: 0 failures 0 warnings (v4.9.66)

by Build bot for Mark Brown

Tree/Branch: v4.9.66 Git describe: v4.9.66 Commit: 8743ce3d7c Linux 4.9.66 Build Time: 101 min 36 sec Passed: 10 / 10 (100.00 %) Failed: 0 / 10 ( 0.00 %) Errors: 0 Warnings: 0 Section Mismatches: 0 ------------------------------------------------------------------------------- defconfigs with issues (other than build errors): ------------------------------------------------------------------------------- =============================================================================== Detailed per-defconfig build reports below: ------------------------------------------------------------------------------- Passed with no errors, warnings or mismatches: arm64-allnoconfig arm64-allmodconfig arm-multi_v5_defconfig arm-multi_v7_defconfig x86_64-defconfig arm-allmodconfig arm-allnoconfig x86_64-allnoconfig arm-multi_v4t_defconfig arm64-defconfig close failed in file object destructor: sys.excepthook is missing lost sys.stderr

7 years

Re: [Linux-stable-mirror] [PATCH 4.14 000/193] 4.14.3-stable review

by Greg Kroah-Hartman

On Tue, Nov 28, 2017 at 07:23:57AM -0800, kernelci.org bot wrote: > stable-rc/linux-4.14.y boot: 239 boots: 11 failed, 197 passed with 31 offline (v4.14.2-194-g9ff910a1edbf) > > Full Boot Summary: https://kernelci.org/boot/all/job/stable-rc/branch/linux-4.14.y/kernel/v4.1… > Full Build Summary: https://kernelci.org/build/stable-rc/branch/linux-4.14.y/kernel/v4.14.2-194… > > Tree: stable-rc > Branch: linux-4.14.y > Git Describe: v4.14.2-194-g9ff910a1edbf > Git Commit: 9ff910a1edbfe3044963b615a4fb2d29f611579d > Git URL: http://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git > Tested: 94 unique boards, 24 SoC families, 21 builds out of 189 > > Boot Regressions Detected: > > arm: > > at91_dt_defconfig: > at91rm9200ek_rootfs:nfs: > lab-free-electrons: failing since 1 day (last pass: v4.14.2 - first fail: v4.14.2-181-g684cdd60a58a) > > sunxi_defconfig: > sun5i-gr8-chip-pro: > lab-free-electrons: new failure (last pass: v4.14.2-181-g684cdd60a58a) > > arm64: > > defconfig: > meson-gxl-s905d-p230: > lab-baylibre-seattle: new failure (last pass: v4.14.2-181-g684cdd60a58a) > meson-gxl-s905x-khadas-vim: > lab-baylibre-seattle: new failure (last pass: v4.14.2-181-g684cdd60a58a) > meson-gxl-s905x-nexbox-a95x: > lab-baylibre-seattle: new failure (last pass: v4.14.2-181-g684cdd60a58a) > meson-gxl-s905x-p212: > lab-baylibre-seattle: new failure (last pass: v4.14.2-181-g684cdd60a58a) > > defconfig+CONFIG_LKDTM=y: > meson-gxl-s905d-p230: > lab-baylibre-seattle: new failure (last pass: v4.14.2-181-g684cdd60a58a) > meson-gxl-s905x-khadas-vim: > lab-baylibre-seattle: new failure (last pass: v4.14.2-181-g684cdd60a58a) > meson-gxl-s905x-p212: > lab-baylibre-seattle: new failure (last pass: v4.14.2-181-g684cdd60a58a) That's a lot of new failures, did I break something? thanks, greg k-h

7 years

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Linux-stable-mirror December 2017