Allow to modify the low-level unbound workqueues cpumask through sysfs. This is performed by traversing the entire workqueue list and calling apply_workqueue_attrs() on the unbound workqueues with the low level mask passed in.
Cc: Christoph Lameter <[email protected]> Cc: Kevin Hilman <[email protected]> Cc: Lai Jiangshan <[email protected]> Cc: Mike Galbraith <[email protected]> Cc: Paul E. McKenney <[email protected]> Cc: Tejun Heo <[email protected]> Cc: Viresh Kumar <[email protected]> Signed-off-by: Frederic Weisbecker <[email protected]> --- kernel/workqueue.c | 81 ++++++++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 78 insertions(+), 3 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 2aa296d..2a12f00 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -293,7 +293,7 @@ static DEFINE_SPINLOCK(wq_mayday_lock); /* protects wq->maydays list */ static LIST_HEAD(workqueues); /* PL: list of all workqueues */ static bool workqueue_freezing; /* PL: have wqs started freezing? */ -static cpumask_var_t wq_unbound_cpumask; +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], @@ -3643,6 +3643,7 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, { struct workqueue_attrs *new_attrs, *tmp_attrs; struct pool_workqueue **pwq_tbl, *dfl_pwq; + cpumask_var_t saved_cpumask; int node, ret; /* only unbound workqueues can change attributes */ @@ -3653,15 +3654,25 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, if (WARN_ON((wq->flags & __WQ_ORDERED) && !attrs->no_numa)) return -EINVAL; + if (!alloc_cpumask_var(&saved_cpumask, GFP_KERNEL)) + goto enomem; + pwq_tbl = kzalloc(wq_numa_tbl_len * 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; /* make a copy of @attrs and sanitize it */ copy_workqueue_attrs(new_attrs, attrs); - cpumask_and(new_attrs->cpumask, new_attrs->cpumask, unbounds_cpumask); + + /* + * Apply unbounds_cpumask on the new attrs for pwq and worker pools + * creation but save the wq proper cpumask for unbound attrs backup. + */ + cpumask_and(saved_cpumask, new_attrs->cpumask, cpu_possible_mask); + cpumask_and(new_attrs->cpumask, saved_cpumask, unbounds_cpumask); /* * We may create multiple pwqs with differing cpumasks. Make a @@ -3693,6 +3704,7 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, /* all pwqs have been created successfully, let's install'em */ mutex_lock(&wq->mutex); + cpumask_copy(new_attrs->cpumask, saved_cpumask); copy_workqueue_attrs(wq->unbound_attrs, new_attrs); /* save the previous pwq and install the new one */ @@ -3713,6 +3725,7 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, ret = 0; /* fall through */ out_free: + free_cpumask_var(saved_cpumask); free_workqueue_attrs(tmp_attrs); free_workqueue_attrs(new_attrs); kfree(pwq_tbl); @@ -3817,6 +3830,7 @@ static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu, goto out_unlock; copy_workqueue_attrs(target_attrs, wq->unbound_attrs); + cpumask_and(target_attrs->cpumask, target_attrs->cpumask, wq_unbound_cpumask); pwq = unbound_pwq_by_node(wq, node); /* @@ -4084,19 +4098,80 @@ static struct bus_type wq_subsys = { .dev_groups = wq_sysfs_groups, }; +static int unbounds_cpumask_apply(cpumask_var_t cpumask) +{ + struct workqueue_struct *wq; + int ret; + + lockdep_assert_held(&wq_pool_mutex); + + list_for_each_entry(wq, &workqueues, list) { + struct workqueue_attrs *attrs; + + if (!(wq->flags & WQ_UNBOUND)) + continue; + + attrs = wq_sysfs_prep_attrs(wq); + if (!attrs) + return -ENOMEM; + + ret = apply_workqueue_attrs_locked(wq, attrs, cpumask); + free_workqueue_attrs(attrs); + if (ret) + break; + } + + return 0; +} + +static ssize_t unbounds_cpumask_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + cpumask_var_t cpumask; + int ret = -EINVAL; + + if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL)) + return -ENOMEM; + + ret = cpumask_parse(buf, cpumask); + if (ret) + goto out; + + get_online_cpus(); + if (cpumask_intersects(cpumask, cpu_online_mask)) { + mutex_lock(&wq_pool_mutex); + ret = unbounds_cpumask_apply(cpumask); + if (ret < 0) { + /* Warn if rollback itself fails */ + WARN_ON_ONCE(unbounds_cpumask_apply(wq_unbound_cpumask)); + } else { + cpumask_copy(wq_unbound_cpumask, cpumask); + } + mutex_unlock(&wq_pool_mutex); + } + put_online_cpus(); +out: + free_cpumask_var(cpumask); + return ret ? ret : count; +} + static ssize_t unbounds_cpumask_show(struct device *dev, struct device_attribute *attr, char *buf) { int written; + mutex_lock(&wq_pool_mutex); written = cpumask_scnprintf(buf, PAGE_SIZE, wq_unbound_cpumask); + mutex_unlock(&wq_pool_mutex); + written += scnprintf(buf + written, PAGE_SIZE - written, "\n"); return written; } static struct device_attribute wq_sysfs_cpumask_attr = - __ATTR(cpumask, 0444, unbounds_cpumask_show, NULL); + __ATTR(cpumask, 0644, unbounds_cpumask_show, unbounds_cpumask_store); static int __init wq_sysfs_init(void) { -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
