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[PATCH] Thin out scan_control: remove nr_to_scan and priority 

Make nr_to_scan and priority a parameter instead of putting it into scan
control.  This allows various small optimizations and IMHO makes the code
easier to read.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Christoph Lameter 2006-03-22 00:08:18 -08:00 committed by Linus Torvalds
parent a07fa3944b
commit 8695949a1d
1 changed files with 25 additions and 34 deletions
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59
mm/vmscan.c
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@ -52,9 +52,6 @@ typedef enum {
} pageout_t;
struct scan_control {
/* Ask refill_inactive_zone, or shrink_cache to scan this many pages */
unsigned long nr_to_scan;
/* Incremented by the number of inactive pages that were scanned */
unsigned long nr_scanned;
@ -63,9 +60,6 @@ struct scan_control {
unsigned long nr_mapped; /* From page_state */
/* Ask shrink_caches, or shrink_zone to scan at this priority */
unsigned int priority;
/* This context's GFP mask */
gfp_t gfp_mask;
@ -1112,11 +1106,10 @@ static int isolate_lru_pages(int nr_to_scan, struct list_head *src,
/*
* shrink_cache() adds the number of pages reclaimed to sc->nr_reclaimed
*/
static void shrink_cache(struct zone *zone, struct scan_control *sc)
static void shrink_cache(int max_scan, struct zone *zone, struct scan_control *sc)
{
LIST_HEAD(page_list);
struct pagevec pvec;
int max_scan = sc->nr_to_scan;
pagevec_init(&pvec, 1);
@ -1192,12 +1185,11 @@ done:
* But we had to alter page->flags anyway.
*/
static void
refill_inactive_zone(struct zone *zone, struct scan_control *sc)
refill_inactive_zone(int nr_pages, struct zone *zone, struct scan_control *sc)
{
int pgmoved;
int pgdeactivate = 0;
int pgscanned;
int nr_pages = sc->nr_to_scan;
LIST_HEAD(l_hold); /* The pages which were snipped off */
LIST_HEAD(l_inactive); /* Pages to go onto the inactive_list */
LIST_HEAD(l_active); /* Pages to go onto the active_list */
@ -1332,10 +1324,11 @@ refill_inactive_zone(struct zone *zone, struct scan_control *sc)
* This is a basic per-zone page freer. Used by both kswapd and direct reclaim.
*/
static void
shrink_zone(struct zone *zone, struct scan_control *sc)
shrink_zone(int priority, struct zone *zone, struct scan_control *sc)
{
unsigned long nr_active;
unsigned long nr_inactive;
unsigned long nr_to_scan;
atomic_inc(&zone->reclaim_in_progress);
@ -1343,14 +1336,14 @@ shrink_zone(struct zone *zone, struct scan_control *sc)
* Add one to `nr_to_scan' just to make sure that the kernel will
* slowly sift through the active list.
*/
zone->nr_scan_active += (zone->nr_active >> sc->priority) + 1;
zone->nr_scan_active += (zone->nr_active >> priority) + 1;
nr_active = zone->nr_scan_active;
if (nr_active >= sc->swap_cluster_max)
zone->nr_scan_active = 0;
else
nr_active = 0;
zone->nr_scan_inactive += (zone->nr_inactive >> sc->priority) + 1;
zone->nr_scan_inactive += (zone->nr_inactive >> priority) + 1;
nr_inactive = zone->nr_scan_inactive;
if (nr_inactive >= sc->swap_cluster_max)
zone->nr_scan_inactive = 0;
@ -1359,17 +1352,17 @@ shrink_zone(struct zone *zone, struct scan_control *sc)
while (nr_active || nr_inactive) {
if (nr_active) {
sc->nr_to_scan = min(nr_active,
nr_to_scan = min(nr_active,
(unsigned long)sc->swap_cluster_max);
nr_active -= sc->nr_to_scan;
refill_inactive_zone(zone, sc);
nr_active -= nr_to_scan;
refill_inactive_zone(nr_to_scan, zone, sc);
}
if (nr_inactive) {
sc->nr_to_scan = min(nr_inactive,
nr_to_scan = min(nr_inactive,
(unsigned long)sc->swap_cluster_max);
nr_inactive -= sc->nr_to_scan;
shrink_cache(zone, sc);
nr_inactive -= nr_to_scan;
shrink_cache(nr_to_scan, zone, sc);
}
}
@ -1395,7 +1388,7 @@ shrink_zone(struct zone *zone, struct scan_control *sc)
* scan then give up on it.
*/
static void
shrink_caches(struct zone **zones, struct scan_control *sc)
shrink_caches(int priority, struct zone **zones, struct scan_control *sc)
{
int i;
@ -1408,14 +1401,14 @@ shrink_caches(struct zone **zones, struct scan_control *sc)
if (!cpuset_zone_allowed(zone, __GFP_HARDWALL))
continue;
zone->temp_priority = sc->priority;
if (zone->prev_priority > sc->priority)
zone->prev_priority = sc->priority;
zone->temp_priority = priority;
if (zone->prev_priority > priority)
zone->prev_priority = priority;
if (zone->all_unreclaimable && sc->priority != DEF_PRIORITY)
if (zone->all_unreclaimable && priority != DEF_PRIORITY)
continue; /* Let kswapd poll it */
shrink_zone(zone, sc);
shrink_zone(priority, zone, sc);
}
}
@ -1462,11 +1455,10 @@ int try_to_free_pages(struct zone **zones, gfp_t gfp_mask)
sc.nr_mapped = read_page_state(nr_mapped);
sc.nr_scanned = 0;
sc.nr_reclaimed = 0;
sc.priority = priority;
sc.swap_cluster_max = SWAP_CLUSTER_MAX;
if (!priority)
disable_swap_token();
shrink_caches(zones, &sc);
shrink_caches(priority, zones, &sc);
shrink_slab(sc.nr_scanned, gfp_mask, lru_pages);
if (reclaim_state) {
sc.nr_reclaimed += reclaim_state->reclaimed_slab;
@ -1629,9 +1621,8 @@ scan:
zone->prev_priority = priority;
sc.nr_scanned = 0;
sc.nr_reclaimed = 0;
sc.priority = priority;
sc.swap_cluster_max = nr_pages? nr_pages : SWAP_CLUSTER_MAX;
shrink_zone(zone, &sc);
shrink_zone(priority, zone, &sc);
reclaim_state->reclaimed_slab = 0;
nr_slab = shrink_slab(sc.nr_scanned, GFP_KERNEL,
lru_pages);
@ -1886,6 +1877,7 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
struct scan_control sc;
cpumask_t mask;
int node_id;
int priority;
if (time_before(jiffies,
zone->last_unsuccessful_zone_reclaim + zone_reclaim_interval))
@ -1906,7 +1898,6 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
sc.may_swap = !!(zone_reclaim_mode & RECLAIM_SWAP);
sc.nr_scanned = 0;
sc.nr_reclaimed = 0;
sc.priority = ZONE_RECLAIM_PRIORITY + 1;
sc.nr_mapped = read_page_state(nr_mapped);
sc.gfp_mask = gfp_mask;
@ -1932,11 +1923,11 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order)
* Free memory by calling shrink zone with increasing priorities
* until we have enough memory freed.
*/
priority = ZONE_RECLAIM_PRIORITY;
do {
sc.priority--;
shrink_zone(zone, &sc);
} while (sc.nr_reclaimed < nr_pages && sc.priority > 0);
shrink_zone(priority, zone, &sc);
priority--;
} while (priority >= 0 && sc.nr_reclaimed < nr_pages);
if (sc.nr_reclaimed < nr_pages && (zone_reclaim_mode & RECLAIM_SLAB)) {
/*