From: Chunguang Xu <brookxu@xxxxxxxxxxx>
Directly use atomic_read(&frn->done.cnt) == 1 to check whether frn
is issued, which makes the code a bit obscure. Maybe we should
replace it with a more understandable function.
Signed-off-by: Chunguang Xu <brookxu@xxxxxxxxxxx>
---
mm/memcontrol.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 3e1384a6..464745b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4542,6 +4542,12 @@ void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
* As being wrong occasionally doesn't matter, updates and accesses to the
* records are lockless and racy.
*/
+
+static inline bool foreign_writeback_in_process(struct memcg_cgwb_frn *frn)
+{
+ return atomic_read(&frn->done.cnt) != 1;
+}
+
void mem_cgroup_track_foreign_dirty_slowpath(struct page *page,
struct bdi_writeback *wb)
{
@@ -4565,7 +4571,7 @@ void mem_cgroup_track_foreign_dirty_slowpath(struct page *page,
frn->memcg_id == wb->memcg_css->id)
break;
if (time_before64(frn->at, oldest_at) &&
- atomic_read(&frn->done.cnt) == 1) {
+ !foreign_writeback_in_process(frn)) {
oldest = i;
oldest_at = frn->at;
}
@@ -4612,7 +4618,7 @@ void mem_cgroup_flush_foreign(struct bdi_writeback *wb)
* already one in flight.
*/
if (time_after64(frn->at, now - intv) &&
- atomic_read(&frn->done.cnt) == 1) {
+ !foreign_writeback_in_process(frn)) {
frn->at = 0;
trace_flush_foreign(wb, frn->bdi_id, frn->memcg_id);
cgroup_writeback_by_id(frn->bdi_id, frn->memcg_id,
--
1.8.3.1
