diff options
| -rw-r--r-- | Documentation/workqueue.txt | 2 | ||||
| -rw-r--r-- | include/linux/workqueue.h | 31 | ||||
| -rw-r--r-- | kernel/workqueue.c | 484 |
3 files changed, 353 insertions, 164 deletions
diff --git a/Documentation/workqueue.txt b/Documentation/workqueue.txt index f81a65b..5e0e05c 100644 --- a/Documentation/workqueue.txt +++ b/Documentation/workqueue.txt @@ -365,7 +365,7 @@ root 5674 0.0 0.0 0 0 ? S 12:13 0:00 [kworker/1:0] If kworkers are going crazy (using too much cpu), there are two types of possible problems: - 1. Something beeing scheduled in rapid succession + 1. Something being scheduled in rapid succession 2. A single work item that consumes lots of cpu cycles The first one can be tracked using tracing: diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index deee212..738b30b 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -424,6 +424,7 @@ struct workqueue_attrs *alloc_workqueue_attrs(gfp_t gfp_mask); void free_workqueue_attrs(struct workqueue_attrs *attrs); int apply_workqueue_attrs(struct workqueue_struct *wq, const struct workqueue_attrs *attrs); +int workqueue_set_unbound_cpumask(cpumask_var_t cpumask); extern bool queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work); @@ -434,7 +435,6 @@ extern bool mod_delayed_work_on(int cpu, struct workqueue_struct *wq, extern void flush_workqueue(struct workqueue_struct *wq); extern void drain_workqueue(struct workqueue_struct *wq); -extern void flush_scheduled_work(void); extern int schedule_on_each_cpu(work_func_t func); @@ -531,6 +531,35 @@ static inline bool schedule_work(struct work_struct *work) } /** + * flush_scheduled_work - ensure that any scheduled work has run to completion. + * + * Forces execution of the kernel-global workqueue and blocks until its + * completion. + * + * Think twice before calling this function! It's very easy to get into + * trouble if you don't take great care. Either of the following situations + * will lead to deadlock: + * + * One of the work items currently on the workqueue needs to acquire + * a lock held by your code or its caller. + * + * Your code is running in the context of a work routine. + * + * They will be detected by lockdep when they occur, but the first might not + * occur very often. It depends on what work items are on the workqueue and + * what locks they need, which you have no control over. + * + * In most situations flushing the entire workqueue is overkill; you merely + * need to know that a particular work item isn't queued and isn't running. + * In such cases you should use cancel_delayed_work_sync() or + * cancel_work_sync() instead. + */ +static inline void flush_scheduled_work(void) +{ + flush_workqueue(system_wq); +} + +/** * schedule_delayed_work_on - queue work in global workqueue on CPU after delay * @cpu: cpu to use * @dwork: job to be done diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 586ad91..5243d4b 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -127,6 +127,11 @@ enum { * * PR: wq_pool_mutex protected for writes. Sched-RCU protected for reads. * + * PW: wq_pool_mutex and wq->mutex protected for writes. Either for reads. + * + * PWR: wq_pool_mutex and wq->mutex protected for writes. Either or + * sched-RCU for reads. + * * WQ: wq->mutex protected. * * WR: wq->mutex protected for writes. Sched-RCU protected for reads. @@ -247,8 +252,8 @@ struct workqueue_struct { int nr_drainers; /* WQ: drain in progress */ int saved_max_active; /* WQ: saved pwq max_active */ - struct workqueue_attrs *unbound_attrs; /* WQ: only for unbound wqs */ - struct pool_workqueue *dfl_pwq; /* WQ: only for unbound wqs */ + struct workqueue_attrs *unbound_attrs; /* PW: only for unbound wqs */ + struct pool_workqueue *dfl_pwq; /* PW: only for unbound wqs */ #ifdef CONFIG_SYSFS struct wq_device *wq_dev; /* I: for sysfs interface */ @@ -268,7 +273,7 @@ struct workqueue_struct { /* hot fields used during command issue, aligned to cacheline */ unsigned int flags ____cacheline_aligned; /* WQ: WQ_* flags */ struct pool_workqueue __percpu *cpu_pwqs; /* I: per-cpu pwqs */ - struct pool_workqueue __rcu *numa_pwq_tbl[]; /* FR: unbound pwqs indexed by node */ + struct pool_workqueue __rcu *numa_pwq_tbl[]; /* PWR: unbound pwqs indexed by node */ }; static struct kmem_cache *pwq_cache; @@ -299,6 +304,8 @@ static DEFINE_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */ static LIST_HEAD(workqueues); /* PR: list of all workqueues */ static bool workqueue_freezing; /* PL: have wqs started freezing? */ +static cpumask_var_t wq_unbound_cpumask; /* PL: low level cpumask for all unbound wqs */ + /* the per-cpu worker pools */ static DEFINE_PER_CPU_SHARED_ALIGNED(struct worker_pool [NR_STD_WORKER_POOLS], cpu_worker_pools); @@ -330,8 +337,6 @@ struct workqueue_struct *system_freezable_power_efficient_wq __read_mostly; EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq); static int worker_thread(void *__worker); -static void copy_workqueue_attrs(struct workqueue_attrs *to, - const struct workqueue_attrs *from); static void workqueue_sysfs_unregister(struct workqueue_struct *wq); #define CREATE_TRACE_POINTS @@ -347,6 +352,12 @@ static void workqueue_sysfs_unregister(struct workqueue_struct *wq); lockdep_is_held(&wq->mutex), \ "sched RCU or wq->mutex should be held") +#define assert_rcu_or_wq_mutex_or_pool_mutex(wq) \ + rcu_lockdep_assert(rcu_read_lock_sched_held() || \ + lockdep_is_held(&wq->mutex) || \ + lockdep_is_held(&wq_pool_mutex), \ + "sched RCU, wq->mutex or wq_pool_mutex should be held") + #define for_each_cpu_worker_pool(pool, cpu) \ for ((pool) = &per_cpu(cpu_worker_pools, cpu)[0]; \ (pool) < &per_cpu(cpu_worker_pools, cpu)[NR_STD_WORKER_POOLS]; \ @@ -551,7 +562,8 @@ static int worker_pool_assign_id(struct worker_pool *pool) * @wq: the target workqueue * @node: the node ID * - * This must be called either with pwq_lock held or sched RCU read locked. + * This must be called with any of wq_pool_mutex, wq->mutex or sched RCU + * read locked. * If the pwq needs to be used beyond the locking in effect, the caller is * responsible for guaranteeing that the pwq stays online. * @@ -560,7 +572,7 @@ static int worker_pool_assign_id(struct worker_pool *pool) static struct pool_workqueue *unbound_pwq_by_node(struct workqueue_struct *wq, int node) { - assert_rcu_or_wq_mutex(wq); + assert_rcu_or_wq_mutex_or_pool_mutex(wq); return rcu_dereference_raw(wq->numa_pwq_tbl[node]); } @@ -976,7 +988,7 @@ static struct worker *find_worker_executing_work(struct worker_pool *pool, * move_linked_works - move linked works to a list * @work: start of series of works to be scheduled * @head: target list to append @work to - * @nextp: out paramter for nested worklist walking + * @nextp: out parameter for nested worklist walking * * Schedule linked works starting from @work to @head. Work series to * be scheduled starts at @work and includes any consecutive work with @@ -2616,7 +2628,7 @@ EXPORT_SYMBOL_GPL(flush_workqueue); * Wait until the workqueue becomes empty. While draining is in progress, * only chain queueing is allowed. IOW, only currently pending or running * work items on @wq can queue further work items on it. @wq is flushed - * repeatedly until it becomes empty. The number of flushing is detemined + * repeatedly until it becomes empty. The number of flushing is determined * by the depth of chaining and should be relatively short. Whine if it * takes too long. */ @@ -2947,36 +2959,6 @@ int schedule_on_each_cpu(work_func_t func) } /** - * flush_scheduled_work - ensure that any scheduled work has run to completion. - * - * Forces execution of the kernel-global workqueue and blocks until its - * completion. - * - * Think twice before calling this function! It's very easy to get into - * trouble if you don't take great care. Either of the following situations - * will lead to deadlock: - * - * One of the work items currently on the workqueue needs to acquire - * a lock held by your code or its caller. - * - * Your code is running in the context of a work routine. - * - * They will be detected by lockdep when they occur, but the first might not - * occur very often. It depends on what work items are on the workqueue and - * what locks they need, which you have no control over. - * - * In most situations flushing the entire workqueue is overkill; you merely - * need to know that a particular work item isn't queued and isn't running. - * In such cases you should use cancel_delayed_work_sync() or - * cancel_work_sync() instead. - */ -void flush_scheduled_work(void) -{ - flush_workqueue(system_wq); -} -EXPORT_SYMBOL(flush_scheduled_work); - -/** * execute_in_process_context - reliably execute the routine with user context * @fn: the function to execute * @ew: guaranteed storage for the execute work structure (must @@ -3081,7 +3063,7 @@ static bool wqattrs_equal(const struct workqueue_attrs *a, * init_worker_pool - initialize a newly zalloc'd worker_pool * @pool: worker_pool to initialize * - * Initiailize a newly zalloc'd @pool. It also allocates @pool->attrs. + * Initialize a newly zalloc'd @pool. It also allocates @pool->attrs. * * Return: 0 on success, -errno on failure. Even on failure, all fields * inside @pool proper are initialized and put_unbound_pool() can be called @@ -3425,20 +3407,9 @@ static struct pool_workqueue *alloc_unbound_pwq(struct workqueue_struct *wq, return pwq; } -/* undo alloc_unbound_pwq(), used only in the error path */ -static void free_unbound_pwq(struct pool_workqueue *pwq) -{ - lockdep_assert_held(&wq_pool_mutex); - - if (pwq) { - put_unbound_pool(pwq->pool); - kmem_cache_free(pwq_cache, pwq); - } -} - /** - * wq_calc_node_mask - calculate a wq_attrs' cpumask for the specified node - * @attrs: the wq_attrs of interest + * wq_calc_node_cpumask - calculate a wq_attrs' cpumask for the specified node + * @attrs: the wq_attrs of the default pwq of the target workqueue * @node: the target NUMA node * @cpu_going_down: if >= 0, the CPU to consider as offline * @cpumask: outarg, the resulting cpumask @@ -3488,6 +3459,7 @@ static struct pool_workqueue *numa_pwq_tbl_install(struct workqueue_struct *wq, { struct pool_workqueue *old_pwq; + lockdep_assert_held(&wq_pool_mutex); lockdep_assert_held(&wq->mutex); /* link_pwq() can handle duplicate calls */ @@ -3498,46 +3470,59 @@ static struct pool_workqueue *numa_pwq_tbl_install(struct workqueue_struct *wq, return old_pwq; } -/** - * apply_workqueue_attrs - apply new workqueue_attrs to an unbound workqueue - * @wq: the target workqueue - * @attrs: the workqueue_attrs to apply, allocated with alloc_workqueue_attrs() - * - * Apply @attrs to an unbound workqueue @wq. Unless disabled, on NUMA - * machines, this function maps a separate pwq to each NUMA node with - * possibles CPUs in @attrs->cpumask so that work items are affine to the - * NUMA node it was issued on. Older pwqs are released as in-flight work - * items finish. Note that a work item which repeatedly requeues itself - * back-to-back will stay on its current pwq. - * - * Performs GFP_KERNEL allocations. - * - * Return: 0 on success and -errno on failure. - */ -int apply_workqueue_attrs(struct workqueue_struct *wq, - const struct workqueue_attrs *attrs) +/* context to store the prepared attrs & pwqs before applying */ +struct apply_wqattrs_ctx { + struct workqueue_struct *wq; /* target workqueue */ + struct workqueue_attrs *attrs; /* attrs to apply */ + struct list_head list; /* queued for batching commit */ + struct pool_workqueue *dfl_pwq; + struct pool_workqueue *pwq_tbl[]; +}; + +/* free the resources after success or abort */ +static void apply_wqattrs_cleanup(struct apply_wqattrs_ctx *ctx) +{ + if (ctx) { + int node; + + for_each_node(node) + put_pwq_unlocked(ctx->pwq_tbl[node]); + put_pwq_unlocked(ctx->dfl_pwq); + + free_workqueue_attrs(ctx->attrs); + + kfree(ctx); + } +} + +/* allocate the attrs and pwqs for later installation */ +static struct apply_wqattrs_ctx * +apply_wqattrs_prepare(struct workqueue_struct *wq, + const struct workqueue_attrs *attrs) { + struct apply_wqattrs_ctx *ctx; struct workqueue_attrs *new_attrs, *tmp_attrs; - struct pool_workqueue **pwq_tbl, *dfl_pwq; - int node, ret; + int node; - /* only unbound workqueues can change attributes */ - if (WARN_ON(!(wq->flags & WQ_UNBOUND))) - return -EINVAL; + lockdep_assert_held(&wq_pool_mutex); - /* creating multiple pwqs breaks ordering guarantee */ - if (WARN_ON((wq->flags & __WQ_ORDERED) && !list_empty(&wq->pwqs))) - return -EINVAL; + ctx = kzalloc(sizeof(*ctx) + nr_node_ids * sizeof(ctx->pwq_tbl[0]), + GFP_KERNEL); - pwq_tbl = kzalloc(nr_node_ids * sizeof(pwq_tbl[0]), GFP_KERNEL); new_attrs = alloc_workqueue_attrs(GFP_KERNEL); tmp_attrs = alloc_workqueue_attrs(GFP_KERNEL); - if (!pwq_tbl || !new_attrs || !tmp_attrs) - goto enomem; + if (!ctx || !new_attrs || !tmp_attrs) + goto out_free; - /* make a copy of @attrs and sanitize it */ + /* + * Calculate the attrs of the default pwq. + * If the user configured cpumask doesn't overlap with the + * wq_unbound_cpumask, we fallback to the wq_unbound_cpumask. + */ copy_workqueue_attrs(new_attrs, attrs); - cpumask_and(new_attrs->cpumask, new_attrs->cpumask, cpu_possible_mask); + cpumask_and(new_attrs->cpumask, new_attrs->cpumask, wq_unbound_cpumask); + if (unlikely(cpumask_empty(new_attrs->cpumask))) + cpumask_copy(new_attrs->cpumask, wq_unbound_cpumask); /* * We may create multiple pwqs with differing cpumasks. Make a @@ -3547,75 +3532,129 @@ int apply_workqueue_attrs(struct workqueue_struct *wq, copy_workqueue_attrs(tmp_attrs, new_attrs); /* - * CPUs should stay stable across pwq creations and installations. - * Pin CPUs, determine the target cpumask for each node and create - * pwqs accordingly. - */ - get_online_cpus(); - - mutex_lock(&wq_pool_mutex); - - /* * If something goes wrong during CPU up/down, we'll fall back to * the default pwq covering whole @attrs->cpumask. Always create * it even if we don't use it immediately. */ - dfl_pwq = alloc_unbound_pwq(wq, new_attrs); - if (!dfl_pwq) - goto enomem_pwq; + ctx->dfl_pwq = alloc_unbound_pwq(wq, new_attrs); + if (!ctx->dfl_pwq) + goto out_free; for_each_node(node) { - if (wq_calc_node_cpumask(attrs, node, -1, tmp_attrs->cpumask)) { - pwq_tbl[node] = alloc_unbound_pwq(wq, tmp_attrs); - if (!pwq_tbl[node]) - goto enomem_pwq; + if (wq_calc_node_cpumask(new_attrs, node, -1, tmp_attrs->cpumask)) { + ctx->pwq_tbl[node] = alloc_unbound_pwq(wq, tmp_attrs); + if (!ctx->pwq_tbl[node]) + goto out_free; } else { - dfl_pwq->refcnt++; - pwq_tbl[node] = dfl_pwq; + ctx->dfl_pwq->refcnt++; + ctx->pwq_tbl[node] = ctx->dfl_pwq; } } - mutex_unlock(&wq_pool_mutex); + /* save the user configured attrs and sanitize it. */ + copy_workqueue_attrs(new_attrs, attrs); + cpumask_and(new_attrs->cpumask, new_attrs->cpumask, cpu_possible_mask); + ctx->attrs = new_attrs; + + ctx->wq = wq; + free_workqueue_attrs(tmp_attrs); + return ctx; + +out_free: + free_workqueue_attrs(tmp_attrs); + free_workqueue_attrs(new_attrs); + apply_wqattrs_cleanup(ctx); + return NULL; +} + +/* set attrs and install prepared pwqs, @ctx points to old pwqs on return */ +static void apply_wqattrs_commit(struct apply_wqattrs_ctx *ctx) +{ + int node; /* all pwqs have been created successfully, let's install'em */ - mutex_lock(&wq->mutex); + mutex_lock(&ctx->wq->mutex); - copy_workqueue_attrs(wq->unbound_attrs, new_attrs); + copy_workqueue_attrs(ctx->wq->unbound_attrs, ctx->attrs); /* save the previous pwq and install the new one */ for_each_node(node) - pwq_tbl[node] = numa_pwq_tbl_install(wq, node, pwq_tbl[node]); + ctx->pwq_tbl[node] = numa_pwq_tbl_install(ctx->wq, node, + ctx->pwq_tbl[node]); /* @dfl_pwq might not have been used, ensure it's linked */ - link_pwq(dfl_pwq); - swap(wq->dfl_pwq, dfl_pwq); + link_pwq(ctx->dfl_pwq); + swap(ctx->wq->dfl_pwq, ctx->dfl_pwq); - mutex_unlock(&wq->mutex); + mutex_unlock(&ctx->wq->mutex); +} - /* put the old pwqs */ - for_each_node(node) - put_pwq_unlocked(pwq_tbl[node]); - put_pwq_unlocked(dfl_pwq); +static void apply_wqattrs_lock(void) +{ + /* CPUs should stay stable across pwq creations and installations */ + get_online_cpus(); + mutex_lock(&wq_pool_mutex); +} +static void apply_wqattrs_unlock(void) +{ + mutex_unlock(&wq_pool_mutex); put_online_cpus(); - ret = 0; - /* fall through */ -out_free: - free_workqueue_attrs(tmp_attrs); - free_workqueue_attrs(new_attrs); - kfree(pwq_tbl); +} + +static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, + const struct workqueue_attrs *attrs) +{ + struct apply_wqattrs_ctx *ctx; + int ret = -ENOMEM; + + /* only unbound workqueues can change attributes */ + if (WARN_ON(!(wq->flags & WQ_UNBOUND))) + return -EINVAL; + + /* creating multiple pwqs breaks ordering guarantee */ + if (WARN_ON((wq->flags & __WQ_ORDERED) && !list_empty(&wq->pwqs))) + return -EINVAL; + + ctx = apply_wqattrs_prepare(wq, attrs); + + /* the ctx has been prepared successfully, let's commit it */ + if (ctx) { + apply_wqattrs_commit(ctx); + ret = 0; + } + + apply_wqattrs_cleanup(ctx); + return ret; +} -enomem_pwq: - free_unbound_pwq(dfl_pwq); - for_each_node(node) - if (pwq_tbl && pwq_tbl[node] != dfl_pwq) - free_unbound_pwq(pwq_tbl[node]); - mutex_unlock(&wq_pool_mutex); - put_online_cpus(); -enomem: - ret = -ENOMEM; - goto out_free; +/** + * apply_workqueue_attrs - apply new workqueue_attrs to an unbound workqueue + * @wq: the target workqueue + * @attrs: the workqueue_attrs to apply, allocated with alloc_workqueue_attrs() + * + * Apply @attrs to an unbound workqueue @wq. Unless disabled, on NUMA + * machines, this function maps a separate pwq to each NUMA node with + * possibles CPUs in @attrs->cpumask so that work items are affine to the + * NUMA node it was issued on. Older pwqs are released as in-flight work + * items finish. Note that a work item which repeatedly requeues itself + * back-to-back will stay on its current pwq. + * + * Performs GFP_KERNEL allocations. + * + * Return: 0 on success and -errno on failure. + */ +int apply_workqueue_attrs(struct workqueue_struct *wq, + const struct workqueue_attrs *attrs) +{ + int ret; + + apply_wqattrs_lock(); + ret = apply_workqueue_attrs_locked(wq, attrs); + apply_wqattrs_unlock(); + + return ret; } /** @@ -3651,7 +3690,8 @@ static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu, lockdep_assert_held(&wq_pool_mutex); - if (!wq_numa_enabled || !(wq->flags & WQ_UNBOUND)) + if (!wq_numa_enabled || !(wq->flags & WQ_UNBOUND) || + wq->unbound_attrs->no_numa) return; /* @@ -3662,48 +3702,37 @@ static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu, target_attrs = wq_update_unbound_numa_attrs_buf; cpumask = target_attrs->cpumask; - mutex_lock(&wq->mutex); - if (wq->unbound_attrs->no_numa) - goto out_unlock; - copy_workqueue_attrs(target_attrs, wq->unbound_attrs); pwq = unbound_pwq_by_node(wq, node); /* * Let's determine what needs to be done. If the target cpumask is - * different from wq's, we need to compare it to @pwq's and create - * a new one if they don't match. If the target cpumask equals - * wq's, the default pwq should be used. + * different from the default pwq's, we need to compare it to @pwq's + * and create a new one if they don't match. If the target cpumask + * equals the default pwq's, the default pwq should be used. */ - if (wq_calc_node_cpumask(wq->unbound_attrs, node, cpu_off, cpumask)) { + if (wq_calc_node_cpumask(wq->dfl_pwq->pool->attrs, node, cpu_off, cpumask)) { if (cpumask_equal(cpumask, pwq->pool->attrs->cpumask)) - goto out_unlock; + return; } else { goto use_dfl_pwq; } - mutex_unlock(&wq->mutex); - /* create a new pwq */ pwq = alloc_unbound_pwq(wq, target_attrs); if (!pwq) { pr_warn("workqueue: allocation failed while updating NUMA affinity of \"%s\"\n", wq->name); - mutex_lock(&wq->mutex); goto use_dfl_pwq; } - /* - * Install the new pwq. As this function is called only from CPU - * hotplug callbacks and applying a new attrs is wrapped with - * get/put_online_cpus(), @wq->unbound_attrs couldn't have changed - * inbetween. - */ + /* Install the new pwq. */ mutex_lock(&wq->mutex); old_pwq = numa_pwq_tbl_install(wq, node, pwq); goto out_unlock; use_dfl_pwq: + mutex_lock(&wq->mutex); spin_lock_irq(&wq->dfl_pwq->pool->lock); get_pwq(wq->dfl_pwq); spin_unlock_irq(&wq->dfl_pwq->pool->lock); @@ -4385,7 +4414,7 @@ static void rebind_workers(struct worker_pool *pool) /* * Restore CPU affinity of all workers. As all idle workers should * be on the run-queue of the associated CPU before any local - * wake-ups for concurrency management happen, restore CPU affinty + * wake-ups for concurrency management happen, restore CPU affinity * of all workers first and then clear UNBOUND. As we're called * from CPU_ONLINE, the following shouldn't fail. */ @@ -4698,6 +4727,82 @@ out_unlock: } #endif /* CONFIG_FREEZER */ +static int workqueue_apply_unbound_cpumask(void) +{ + LIST_HEAD(ctxs); + int ret = 0; + struct workqueue_struct *wq; + struct apply_wqattrs_ctx *ctx, *n; + + lockdep_assert_held(&wq_pool_mutex); + + list_for_each_entry(wq, &workqueues, list) { + if (!(wq->flags & WQ_UNBOUND)) + continue; + /* creating multiple pwqs breaks ordering guarantee */ + if (wq->flags & __WQ_ORDERED) + continue; + + ctx = apply_wqattrs_prepare(wq, wq->unbound_attrs); + if (!ctx) { + ret = -ENOMEM; + break; + } + + list_add_tail(&ctx->list, &ctxs); + } + + list_for_each_entry_safe(ctx, n, &ctxs, list) { + if (!ret) + apply_wqattrs_commit(ctx); + apply_wqattrs_cleanup(ctx); + } + + return ret; +} + +/** + * workqueue_set_unbound_cpumask - Set the low-level unbound cpumask + * @cpumask: the cpumask to set + * + * The low-level workqueues cpumask is a global cpumask that limits + * the affinity of all unbound workqueues. This function check the @cpumask + * and apply it to all unbound workqueues and updates all pwqs of them. + * + * Retun: 0 - Success + * -EINVAL - Invalid @cpumask + * -ENOMEM - Failed to allocate memory for attrs or pwqs. + */ +int workqueue_set_unbound_cpumask(cpumask_var_t cpumask) +{ + int ret = -EINVAL; + cpumask_var_t saved_cpumask; + + if (!zalloc_cpumask_var(&saved_cpumask, GFP_KERNEL)) + return -ENOMEM; + + cpumask_and(cpumask, cpumask, cpu_possible_mask); + if (!cpumask_empty(cpumask)) { + apply_wqattrs_lock(); + + /* save the old wq_unbound_cpumask. */ + cpumask_copy(saved_cpumask, wq_unbound_cpumask); + + /* update wq_unbound_cpumask at first and apply it to wqs. */ + cpumask_copy(wq_unbound_cpumask, cpumask); + ret = workqueue_apply_unbound_cpumask(); + + /* restore the wq_unbound_cpumask when failed. */ + if (ret < 0) + cpumask_copy(wq_unbound_cpumask, saved_cpumask); + + apply_wqattrs_unlock(); + } + + free_cpumask_var(saved_cpumask); + return ret; +} + #ifdef CONFIG_SYSFS /* * Workqueues with WQ_SYSFS flag set is visible to userland via @@ -4802,13 +4907,13 @@ static struct workqueue_attrs *wq_sysfs_prep_attrs(struct workqueue_struct *wq) { struct workqueue_attrs *attrs; + lockdep_assert_held(&wq_pool_mutex); + attrs = alloc_workqueue_attrs(GFP_KERNEL); if (!attrs) return NULL; - mutex_lock(&wq->mutex); copy_workqueue_attrs(attrs, wq->unbound_attrs); - mutex_unlock(&wq->mutex); return attrs; } @@ -4817,18 +4922,22 @@ static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr, { struct workqueue_struct *wq = dev_to_wq(dev); struct workqueue_attrs *attrs; - int ret; + int ret = -ENOMEM; + + apply_wqattrs_lock(); attrs = wq_sysfs_prep_attrs(wq); if (!attrs) - return -ENOMEM; + goto out_unlock; if (sscanf(buf, "%d", &attrs->nice) == 1 && attrs->nice >= MIN_NICE && attrs->nice <= MAX_NICE) - ret = apply_workqueue_attrs(wq, attrs); + ret = apply_workqueue_attrs_locked(wq, attrs); else ret = -EINVAL; +out_unlock: + apply_wqattrs_unlock(); free_workqueue_attrs(attrs); return ret ?: count; } @@ -4852,16 +4961,20 @@ static ssize_t wq_cpumask_store(struct device *dev, { struct workqueue_struct *wq = dev_to_wq(dev); struct workqueue_attrs *attrs; - int ret; + int ret = -ENOMEM; + + apply_wqattrs_lock(); attrs = wq_sysfs_prep_attrs(wq); if (!attrs) - return -ENOMEM; + goto out_unlock; ret = cpumask_parse(buf, attrs->cpumask); if (!ret) - ret = apply_workqueue_attrs(wq, attrs); + ret = apply_workqueue_attrs_locked(wq, attrs); +out_unlock: + apply_wqattrs_unlock(); free_workqueue_attrs(attrs); return ret ?: count; } @@ -4885,18 +4998,22 @@ static ssize_t wq_numa_store(struct device *dev, struct device_attribute *attr, { struct workqueue_struct *wq = dev_to_wq(dev); struct workqueue_attrs *attrs; - int v, ret; + int v, ret = -ENOMEM; + + apply_wqattrs_lock(); attrs = wq_sysfs_prep_attrs(wq); if (!attrs) - return -ENOMEM; + goto out_unlock; ret = -EINVAL; if (sscanf(buf, "%d", &v) == 1) { attrs->no_numa = !v; - ret = apply_workqueue_attrs(wq, attrs); + ret = apply_workqueue_attrs_locked(wq, attrs); } +out_unlock: + apply_wqattrs_unlock(); free_workqueue_attrs(attrs); return ret ?: count; } @@ -4914,9 +5031,49 @@ static struct bus_type wq_subsys = { .dev_groups = wq_sysfs_groups, }; +static ssize_t wq_unbound_cpumask_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int written; + + mutex_lock(&wq_pool_mutex); + written = scnprintf(buf, PAGE_SIZE, "%*pb\n", + cpumask_pr_args(wq_unbound_cpumask)); + mutex_unlock(&wq_pool_mutex); + + return written; +} + +static ssize_t wq_unbound_cpumask_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t count) +{ + cpumask_var_t cpumask; + int ret; + + if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL)) + return -ENOMEM; + + ret = cpumask_parse(buf, cpumask); + if (!ret) + ret = workqueue_set_unbound_cpumask(cpumask); + + free_cpumask_var(cpumask); + return ret ? ret : count; +} + +static struct device_attribute wq_sysfs_cpumask_attr = + __ATTR(cpumask, 0644, wq_unbound_cpumask_show, + wq_unbound_cpumask_store); + static int __init wq_sysfs_init(void) { - return subsys_virtual_register(&wq_subsys, NULL); + int err; + + err = subsys_virtual_register(&wq_subsys, NULL); + if (err) + return err; + + return device_create_file(wq_subsys.dev_root, &wq_sysfs_cpumask_attr); } core_initcall(wq_sysfs_init); @@ -4948,7 +5105,7 @@ int workqueue_sysfs_register(struct workqueue_struct *wq) int ret; /* - * Adjusting max_active or creating new pwqs by applyting + * Adjusting max_active or creating new pwqs by applying * attributes breaks ordering guarantee. Disallow exposing ordered * workqueues. */ @@ -5064,6 +5221,9 @@ static int __init init_workqueues(void) WARN_ON(__alignof__(struct pool_workqueue) < __alignof__(long long)); + BUG_ON(!alloc_cpumask_var(&wq_unbound_cpumask, GFP_KERNEL)); + cpumask_copy(wq_unbound_cpumask, cpu_possible_mask); + pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC); cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_UP); |