mm/vmscan.c: use DIV_ROUND_UP for calculation of zone's balance_gap and correct comments.
Currently, we use (zone->managed_pages + KSWAPD_ZONE_BALANCE_GAP_RATIO-1) / KSWAPD_ZONE_BALANCE_GAP_RATIO to avoid a zero gap value. It's better to use DIV_ROUND_UP macro for neater code and clear meaning. Besides, the gap value is calculated against the per-zone "managed pages", not "present pages". This patch also corrects the comment and do some rephrasing. Signed-off-by: Jianyu Zhan <nasa4836@gmail.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Rafael Aquini <aquini@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Родитель
b7596fb43a
Коммит
4be89a3460
|
@ -166,10 +166,10 @@ enum {
|
|||
#define COMPACT_CLUSTER_MAX SWAP_CLUSTER_MAX
|
||||
|
||||
/*
|
||||
* Ratio between the present memory in the zone and the "gap" that
|
||||
* we're allowing kswapd to shrink in addition to the per-zone high
|
||||
* wmark, even for zones that already have the high wmark satisfied,
|
||||
* in order to provide better per-zone lru behavior. We are ok to
|
||||
* Ratio between zone->managed_pages and the "gap" that above the per-zone
|
||||
* "high_wmark". While balancing nodes, We allow kswapd to shrink zones that
|
||||
* do not meet the (high_wmark + gap) watermark, even which already met the
|
||||
* high_wmark, in order to provide better per-zone lru behavior. We are ok to
|
||||
* spend not more than 1% of the memory for this zone balancing "gap".
|
||||
*/
|
||||
#define KSWAPD_ZONE_BALANCE_GAP_RATIO 100
|
||||
|
|
10
mm/vmscan.c
10
mm/vmscan.c
|
@ -2295,9 +2295,8 @@ static inline bool compaction_ready(struct zone *zone, struct scan_control *sc)
|
|||
* there is a buffer of free pages available to give compaction
|
||||
* a reasonable chance of completing and allocating the page
|
||||
*/
|
||||
balance_gap = min(low_wmark_pages(zone),
|
||||
(zone->managed_pages + KSWAPD_ZONE_BALANCE_GAP_RATIO-1) /
|
||||
KSWAPD_ZONE_BALANCE_GAP_RATIO);
|
||||
balance_gap = min(low_wmark_pages(zone), DIV_ROUND_UP(
|
||||
zone->managed_pages, KSWAPD_ZONE_BALANCE_GAP_RATIO));
|
||||
watermark = high_wmark_pages(zone) + balance_gap + (2UL << sc->order);
|
||||
watermark_ok = zone_watermark_ok_safe(zone, 0, watermark, 0, 0);
|
||||
|
||||
|
@ -2949,9 +2948,8 @@ static bool kswapd_shrink_zone(struct zone *zone,
|
|||
* high wmark plus a "gap" where the gap is either the low
|
||||
* watermark or 1% of the zone, whichever is smaller.
|
||||
*/
|
||||
balance_gap = min(low_wmark_pages(zone),
|
||||
(zone->managed_pages + KSWAPD_ZONE_BALANCE_GAP_RATIO-1) /
|
||||
KSWAPD_ZONE_BALANCE_GAP_RATIO);
|
||||
balance_gap = min(low_wmark_pages(zone), DIV_ROUND_UP(
|
||||
zone->managed_pages, KSWAPD_ZONE_BALANCE_GAP_RATIO));
|
||||
|
||||
/*
|
||||
* If there is no low memory pressure or the zone is balanced then no
|
||||
|
|
Загрузка…
Ссылка в новой задаче