Now that we have a dedicated kthread in place to perform targeted region
evacuation, add and export a mechanism to queue work to the kthread.
Adding work to kmempowerd is very simple: just set the bits corresponding
to the region numbers that we want to evacuate, and queue the work item
to the kthread.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 26 ++++++++++++++++++++++++++
mm/internal.h | 3 +++
2 files changed, 29 insertions(+)
diff --git a/mm/compaction.c b/mm/compaction.c
index 0511eae..b56be89 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -1271,6 +1271,32 @@ int evacuate_mem_region(struct zone *z, struct zone_mem_region *zmr)
#define nr_zone_region_bits MAX_NR_ZONE_REGIONS
static DECLARE_BITMAP(mpwork_mask, nr_zone_region_bits);
+void queue_mempower_work(struct pglist_data *pgdat, struct zone *zone,
+ int region_id)
+{
+ struct mempower_work *mpwork;
+ unsigned long flags;
+
+ mpwork = &zone->mempower_work;
+ spin_lock_irqsave(&mpwork->lock, flags);
+ set_bit(region_id, mpwork->mempower_mask);
+ spin_unlock_irqrestore(&mpwork->lock, flags);
+
+ /*
+ * The kmempowerd kthread will never miss the work we assign it,
+ * due to the way queue_kthread_work() and kthread_worker_fn()
+ * synchronize with each other. If the work is currently executing,
+ * it gets requeued; but if it is pending, the kthread will naturally
+ * process it in the future. Eitherway, it will notice and process
+ * all the work submitted to it, and won't prematurely go to sleep.
+ *
+ * Note: The bits set in the mempower_mask represent the actual
+ * "work" for the kthread. The work-struct is just a container used
+ * to communicate that work to the kthread.
+ */
+ queue_kthread_work(&pgdat->mempower_worker, &mpwork->work);
+}
+
static void kmempowerd(struct kthread_work *work)
{
struct mempower_work *mpwork;
diff --git a/mm/internal.h b/mm/internal.h
index acb50f8..3fbc9f6 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -181,6 +181,9 @@ int compact_range(struct compact_control *cc, struct aggression_control *ac,
struct free_page_control *fc, unsigned long start,
unsigned long end);
+void queue_mempower_work(struct pglist_data *pgdat, struct zone *zone,
+ int region_id);
+
#endif
/*
--
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