[PATCH v8 03/14] lru_add_drain_all: factor out lru_add_drain_needed

Chris Metcalf
2015-10-20T20:36:51Z

This per-cpu check was being done in the loop in lru_add_drain_all(),
but having it be callable for a particular cpu is helpful for the
task-isolation patches.

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
---
include/linux/swap.h | 1 +
mm/swap.c | 13 +++++++++----
2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/include/linux/swap.h b/include/linux/swap.h
index 7ba7dccaf0e7..66719610c9f5 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -305,6 +305,7 @@ extern void activate_page(struct page *);
extern void mark_page_accessed(struct page *);
extern void lru_add_drain(void);
extern void lru_add_drain_cpu(int cpu);
+extern bool lru_add_drain_needed(int cpu);
extern void lru_add_drain_all(void);
extern void rotate_reclaimable_page(struct page *page);
extern void deactivate_file_page(struct page *page);
diff --git a/mm/swap.c b/mm/swap.c
index 983f692a47fd..e21f3357cedd 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -854,6 +854,14 @@ void deactivate_file_page(struct page *page)
}
}

+bool lru_add_drain_needed(int cpu)
+{
+ return (pagevec_count(&per_cpu(lru_add_pvec, cpu)) ||
+ pagevec_count(&per_cpu(lru_rotate_pvecs, cpu)) ||
+ pagevec_count(&per_cpu(lru_deactivate_file_pvecs, cpu)) ||
+ need_activate_page_drain(cpu));
+}
+
void lru_add_drain(void)
{
lru_add_drain_cpu(get_cpu());
@@ -880,10 +888,7 @@ void lru_add_drain_all(void)
for_each_online_cpu(cpu) {
struct work_struct *work = &per_cpu(lru_add_drain_work, cpu);

- if (pagevec_count(&per_cpu(lru_add_pvec, cpu)) ||
- pagevec_count(&per_cpu(lru_rotate_pvecs, cpu)) ||
- pagevec_count(&per_cpu(lru_deactivate_file_pvecs, cpu)) ||
- need_activate_page_drain(cpu)) {
+ if (lru_add_drain_needed(cpu)) {
INIT_WORK(work, lru_add_drain_per_cpu);
schedule_work_on(cpu, work);
cpumask_set_cpu(cpu, &has_work);
--
2.1.2