diff options
Diffstat (limited to 'module')
| -rw-r--r-- | module/spl/spl-taskq.c | 47 | ||||
| -rw-r--r-- | module/splat/splat-taskq.c | 29 |
2 files changed, 48 insertions, 28 deletions
diff --git a/module/spl/spl-taskq.c b/module/spl/spl-taskq.c index 201cb5949..5a17f1ccf 100644 --- a/module/spl/spl-taskq.c +++ b/module/spl/spl-taskq.c @@ -78,35 +78,36 @@ retry: if (flags & TQ_NOSLEEP) SRETURN(NULL); - /* Sleep periodically polling the free list for an available - * spl_task_t. If a full second passes and we have not found - * one gives up and return a NULL to the caller. */ - if (flags & TQ_SLEEP) { - spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags); - schedule_timeout(HZ / 100); - spin_lock_irqsave(&tq->tq_lock, tq->tq_lock_flags); - if (count < 100) - SGOTO(retry, count++); - - SRETURN(NULL); - } - - /* Unreachable, Neither TQ_SLEEP or TQ_NOSLEEP set */ - PANIC("Neither TQ_SLEEP or TQ_NOSLEEP set"); + /* + * Sleep periodically polling the free list for an available + * spl_task_t. Dispatching with TQ_SLEEP should always succeed + * but we cannot block forever waiting for an spl_taskq_t to + * show up in the free list, otherwise a deadlock can happen. + * + * Therefore, we need to allocate a new task even if the number + * of allocated tasks is above tq->tq_maxalloc, but we still + * end up delaying the task allocation by one second, thereby + * throttling the task dispatch rate. + */ + spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags); + schedule_timeout(HZ / 100); + spin_lock_irqsave(&tq->tq_lock, tq->tq_lock_flags); + if (count < 100) + SGOTO(retry, count++); } - spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags); + spin_unlock_irqrestore(&tq->tq_lock, tq->tq_lock_flags); t = kmem_alloc(sizeof(spl_task_t), flags & (TQ_SLEEP | TQ_NOSLEEP)); spin_lock_irqsave(&tq->tq_lock, tq->tq_lock_flags); - if (t) { - spin_lock_init(&t->t_lock); + if (t) { + spin_lock_init(&t->t_lock); INIT_LIST_HEAD(&t->t_list); - t->t_id = 0; - t->t_func = NULL; - t->t_arg = NULL; - tq->tq_nalloc++; - } + t->t_id = 0; + t->t_func = NULL; + t->t_arg = NULL; + tq->tq_nalloc++; + } SRETURN(t); } diff --git a/module/splat/splat-taskq.c b/module/splat/splat-taskq.c index d4540f37a..a7c537236 100644 --- a/module/splat/splat-taskq.c +++ b/module/splat/splat-taskq.c @@ -296,6 +296,10 @@ splat_taskq_test3(struct file *file, void *arg) * Then use taskq_wait() to block until all the tasks complete, then * cross check that all the tasks ran by checking tg_arg->count which * is incremented in the task function. Finally cleanup the taskq. + * + * First we try with a large 'maxalloc' value, then we try with a small one. + * We should not drop tasks when TQ_SLEEP is used in taskq_dispatch(), even + * if the number of pending tasks is above maxalloc. */ static void splat_taskq_test4_func(void *arg) @@ -307,16 +311,18 @@ splat_taskq_test4_func(void *arg) } static int -splat_taskq_test4(struct file *file, void *arg) +splat_taskq_test4_common(struct file *file, void *arg, int minalloc, + int maxalloc, int nr_tasks) { taskq_t *tq; splat_taskq_arg_t tq_arg; int i, j, rc = 0; - splat_vprint(file, SPLAT_TASKQ_TEST4_NAME, "Taskq '%s' creating\n", - SPLAT_TASKQ_TEST4_NAME); + splat_vprint(file, SPLAT_TASKQ_TEST4_NAME, "Taskq '%s' creating " + "(%d/%d/%d)\n", SPLAT_TASKQ_TEST4_NAME, minalloc, maxalloc, + nr_tasks); if ((tq = taskq_create(SPLAT_TASKQ_TEST4_NAME, 1, maxclsyspri, - 50, INT_MAX, TASKQ_PREPOPULATE)) == NULL) { + minalloc, maxalloc, TASKQ_PREPOPULATE)) == NULL) { splat_vprint(file, SPLAT_TASKQ_TEST4_NAME, "Taskq '%s' create failed\n", SPLAT_TASKQ_TEST4_NAME); @@ -326,7 +332,7 @@ splat_taskq_test4(struct file *file, void *arg) tq_arg.file = file; tq_arg.name = SPLAT_TASKQ_TEST4_NAME; - for (i = 1; i <= 1024; i *= 2) { + for (i = 1; i <= nr_tasks; i *= 2) { atomic_set(&tq_arg.count, 0); splat_vprint(file, SPLAT_TASKQ_TEST4_NAME, "Taskq '%s' function '%s' dispatched %d times\n", @@ -364,6 +370,19 @@ out: return rc; } +static int splat_taskq_test4(struct file *file, void *arg) +{ + int rc; + + rc = splat_taskq_test4_common(file, arg, 50, INT_MAX, 1024); + if (rc) + return rc; + + rc = splat_taskq_test4_common(file, arg, 1, 1, 32); + + return rc; +} + /* * Create a taskq and dispatch a specific sequence of tasks carefully * crafted to validate the order in which tasks are processed. When |