2023-04-11 06:21:32

by Haifeng Xu

Subject: [PATCH RESEND] mm/vmscan: simplify shrink_node()

The difference between sc->nr_reclaimed and nr_reclaimed is computed
three times. Introduce a new variable to record the value, so it only
needs to be computed once.

Signed-off-by: Haifeng Xu <[email protected]>
---
mm/vmscan.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9c1c5e8b24b8..b86573104974 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -6451,7 +6451,7 @@ static void shrink_node_memcgs(pg_data_t *pgdat, struct scan_control *sc)
static void shrink_node(pg_data_t *pgdat, struct scan_control *sc)
{
struct reclaim_state *reclaim_state = current->reclaim_state;
- unsigned long nr_reclaimed, nr_scanned;
+ unsigned long nr_reclaimed, nr_scanned, nr_node_reclaimed;
struct lruvec *target_lruvec;
bool reclaimable = false;

@@ -6477,13 +6477,14 @@ static void shrink_node(pg_data_t *pgdat, struct scan_control *sc)
reclaim_state->reclaimed_slab = 0;
}

+ nr_node_reclaimed = sc->nr_reclaimed - nr_reclaimed;
+
/* Record the subtree's reclaim efficiency */
if (!sc->proactive)
vmpressure(sc->gfp_mask, sc->target_mem_cgroup, true,
- sc->nr_scanned - nr_scanned,
- sc->nr_reclaimed - nr_reclaimed);
+ sc->nr_scanned - nr_scanned, nr_node_reclaimed);

- if (sc->nr_reclaimed - nr_reclaimed)
+ if (nr_node_reclaimed)
reclaimable = true;

if (current_is_kswapd()) {
@@ -6545,8 +6546,7 @@ static void shrink_node(pg_data_t *pgdat, struct scan_control *sc)
test_bit(LRUVEC_CONGESTED, &target_lruvec->flags))
reclaim_throttle(pgdat, VMSCAN_THROTTLE_CONGESTED);

- if (should_continue_reclaim(pgdat, sc->nr_reclaimed - nr_reclaimed,
- sc))
+ if (should_continue_reclaim(pgdat, nr_node_reclaimed, sc))
goto again;

/*
--
2.25.1

2023-04-12 08:06:07

by David Hildenbrand

Subject: Re: [PATCH RESEND] mm/vmscan: simplify shrink_node()

On 11.04.23 08:17, Haifeng Xu wrote:
> The difference between sc->nr_reclaimed and nr_reclaimed is computed
> three times. Introduce a new variable to record the value, so it only
> needs to be computed once.
>
> Signed-off-by: Haifeng Xu <[email protected]>
> ---


Reviewed-by: David Hildenbrand <[email protected]>

--
Thanks,

David / dhildenb