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Subject[PATCH 26/34] mm, vmscan: avoid passing in remaining unnecessarily to prepare_kswapd_sleep
Date
As pointed out by Minchan Kim, the first call to prepare_kswapd_sleep
always passes in 0 for remaining and the second call can trivially
check the parameter in advance.

Suggested-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
mm/vmscan.c | 12 ++++--------
1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6d5c78e2312b..8a67aa53aa7b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3020,15 +3020,10 @@ static bool zone_balanced(struct zone *zone, int order, int classzone_idx)
*
* Returns true if kswapd is ready to sleep
*/
-static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, long remaining,
- int classzone_idx)
+static bool prepare_kswapd_sleep(pg_data_t *pgdat, int order, int classzone_idx)
{
int i;

- /* If a direct reclaimer woke kswapd within HZ/10, it's premature */
- if (remaining)
- return false;
-
/*
* The throttled processes are normally woken up in balance_pgdat() as
* soon as pfmemalloc_watermark_ok() is true. But there is a potential
@@ -3243,7 +3238,7 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int alloc_order, int reclaim_o
prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);

/* Try to sleep for a short interval */
- if (prepare_kswapd_sleep(pgdat, reclaim_order, remaining, classzone_idx)) {
+ if (prepare_kswapd_sleep(pgdat, reclaim_order, classzone_idx)) {
/*
* Compaction records what page blocks it recently failed to
* isolate pages from and skips them in the future scanning.
@@ -3278,7 +3273,8 @@ static void kswapd_try_to_sleep(pg_data_t *pgdat, int alloc_order, int reclaim_o
* After a short sleep, check if it was a premature sleep. If not, then
* go fully to sleep until explicitly woken up.
*/
- if (prepare_kswapd_sleep(pgdat, reclaim_order, remaining, classzone_idx)) {
+ if (!remaining &&
+ prepare_kswapd_sleep(pgdat, reclaim_order, classzone_idx)) {
trace_mm_vmscan_kswapd_sleep(pgdat->node_id);

/*
--
2.6.4
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