This creates a system memory reclaim work queue and has lru_add_drain_all use this new work queue. This allows memory reclaim work that invalidates block devices to flush all lru add caches without triggering the check_flush_dependency warning.
Signed-off-by: Keith Busch <[email protected]> --- This is similar to proposal a few months ago: https://patchwork.ozlabs.org/patch/574623/ The difference from this patch is this one uses a system workqueue so others can use a memory reclaim workqueue without having to allocate their own. I didn't see any follow up on linux-mm on if lru_add_drain_per_cpu should be using a WQ_MEM_RECLAIM set work queue, so sending a similar patch since warnings are frequently being triggered. include/linux/workqueue.h | 1 + kernel/workqueue.c | 5 ++++- mm/swap.c | 2 +- 3 files changed, 6 insertions(+), 2 deletions(-) diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index ca73c50..8c79e82 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -357,6 +357,7 @@ extern struct workqueue_struct *system_unbound_wq; extern struct workqueue_struct *system_freezable_wq; extern struct workqueue_struct *system_power_efficient_wq; extern struct workqueue_struct *system_freezable_power_efficient_wq; +extern struct workqueue_struct *system_mem_wq; extern struct workqueue_struct * __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active, diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 5f5068e..7e9050a 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -341,6 +341,8 @@ struct workqueue_struct *system_long_wq __read_mostly; EXPORT_SYMBOL_GPL(system_long_wq); struct workqueue_struct *system_unbound_wq __read_mostly; EXPORT_SYMBOL_GPL(system_unbound_wq); +struct workqueue_struct *system_mem_wq __read_mostly; +EXPORT_SYMBOL(system_mem_wq); struct workqueue_struct *system_freezable_wq __read_mostly; EXPORT_SYMBOL_GPL(system_freezable_wq); struct workqueue_struct *system_power_efficient_wq __read_mostly; @@ -5574,6 +5576,7 @@ static int __init init_workqueues(void) system_long_wq = alloc_workqueue("events_long", 0, 0); system_unbound_wq = alloc_workqueue("events_unbound", WQ_UNBOUND, WQ_UNBOUND_MAX_ACTIVE); + system_mem_wq = alloc_workqueue("events_mem_unbound", WQ_UNBOUND | WQ_MEM_RECLAIM, 0); system_freezable_wq = alloc_workqueue("events_freezable", WQ_FREEZABLE, 0); system_power_efficient_wq = alloc_workqueue("events_power_efficient", @@ -5582,7 +5585,7 @@ static int __init init_workqueues(void) WQ_FREEZABLE | WQ_POWER_EFFICIENT, 0); BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq || - !system_unbound_wq || !system_freezable_wq || + !system_mem_wq || !system_unbound_wq || !system_freezable_wq || !system_power_efficient_wq || !system_freezable_power_efficient_wq); diff --git a/mm/swap.c b/mm/swap.c index 03aacbc..ade23de 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -685,7 +685,7 @@ void lru_add_drain_all(void) pagevec_count(&per_cpu(lru_deactivate_pvecs, cpu)) || need_activate_page_drain(cpu)) { INIT_WORK(work, lru_add_drain_per_cpu); - schedule_work_on(cpu, work); + queue_work_on(cpu, system_mem_wq, work); cpumask_set_cpu(cpu, &has_work); } } -- 2.7.2
