[PATCH 11/16] mm: let sc.nr_scanned/sc.nr_reclaimed accumulate

From: Wu Fengguang
Date: Wed Dec 07 2005 - 05:28:08 EST


Now that there's no need to keep track of nr_scanned/nr_reclaimed for every
single round of shrink_zone(), remove the total_scanned/total_reclaimed and
let nr_scanned/nr_reclaimed accumulate between shrink_zone() calls.

Signed-off-by: Wu Fengguang <wfg@xxxxxxxxxxxxxxxx>
---

mm/vmscan.c | 36 ++++++++++++++----------------------
1 files changed, 14 insertions(+), 22 deletions(-)

--- linux.orig/mm/vmscan.c
+++ linux/mm/vmscan.c
@@ -1231,7 +1231,6 @@ int try_to_free_pages(struct zone **zone
{
int priority;
int ret = 0;
- int total_scanned = 0, total_reclaimed = 0;
struct reclaim_state *reclaim_state = current->reclaim_state;
struct scan_control sc;
int i;
@@ -1241,6 +1240,8 @@ int try_to_free_pages(struct zone **zone
sc.gfp_mask = gfp_mask;
sc.may_writepage = 0;
sc.may_swap = 1;
+ sc.nr_scanned = 0;
+ sc.nr_reclaimed = 0;

inc_page_state(allocstall);

@@ -1261,8 +1262,6 @@ int try_to_free_pages(struct zone **zone
*/
for (priority = DEF_PRIORITY + PRIORITY_STEPS; priority >= 0; priority--) {
sc.nr_mapped = read_page_state(nr_mapped);
- sc.nr_scanned = 0;
- sc.nr_reclaimed = 0;
sc.priority = priority;
sc.nr_to_reclaim = SWAP_CLUSTER_MAX;
if (!priority)
@@ -1274,9 +1273,7 @@ int try_to_free_pages(struct zone **zone
sc.nr_reclaimed += reclaim_state->reclaimed_slab;
reclaim_state->reclaimed_slab = 0;
}
- total_scanned += sc.nr_scanned;
- total_reclaimed += sc.nr_reclaimed;
- if (total_reclaimed >= SWAP_CLUSTER_MAX) {
+ if (sc.nr_reclaimed >= SWAP_CLUSTER_MAX) {
ret = 1;
goto out;
}
@@ -1288,13 +1285,13 @@ int try_to_free_pages(struct zone **zone
* that's undesirable in laptop mode, where we *want* lumpy
* writeout. So in laptop mode, write out the whole world.
*/
- if (total_scanned > SWAP_CLUSTER_MAX * 3 / 2) {
- wakeup_pdflush(laptop_mode ? 0 : total_scanned);
+ if (sc.nr_scanned > SWAP_CLUSTER_MAX * 3 / 2) {
+ wakeup_pdflush(laptop_mode ? 0 : sc.nr_scanned);
sc.may_writepage = 1;
}

/* Take a nap, wait for some writeback to complete */
- if (sc.nr_scanned && priority < DEF_PRIORITY - PRIORITY_STEPS)
+ if (priority < DEF_PRIORITY - PRIORITY_STEPS)
blk_congestion_wait(WRITE, HZ/10);
}
out:
@@ -1340,18 +1337,17 @@ static int balance_pgdat(pg_data_t *pgda
int all_zones_ok;
int priority;
int i;
- int total_scanned, total_reclaimed;
struct reclaim_state *reclaim_state = current->reclaim_state;
struct scan_control sc;
struct zone *prev_zone = pgdat->node_zones;

loop_again:
- total_scanned = 0;
- total_reclaimed = 0;
sc.gfp_mask = GFP_KERNEL;
sc.may_writepage = 0;
sc.may_swap = 1;
sc.nr_mapped = read_page_state(nr_mapped);
+ sc.nr_scanned = 0;
+ sc.nr_reclaimed = 0;

inc_page_state(pageoutrun);

@@ -1366,8 +1362,6 @@ loop_again:

for (priority = DEF_PRIORITY; priority >= 0; priority--) {
all_zones_ok = 1;
- sc.nr_scanned = 0;
- sc.nr_reclaimed = 0;
sc.priority = priority;
sc.nr_to_reclaim = nr_pages ? nr_pages : SWAP_CLUSTER_MAX;

@@ -1437,19 +1431,17 @@ scan_swspd:
reclaim_state->reclaimed_slab = 0;
shrink_slab(prev_zone, priority, GFP_KERNEL);
sc.nr_reclaimed += reclaim_state->reclaimed_slab;
- total_reclaimed += sc.nr_reclaimed;
- total_scanned += sc.nr_scanned;

/*
* If we've done a decent amount of scanning and
* the reclaim ratio is low, start doing writepage
* even in laptop mode
*/
- if (total_scanned > SWAP_CLUSTER_MAX * 2 &&
- total_scanned > total_reclaimed+total_reclaimed/2)
+ if (sc.nr_scanned > SWAP_CLUSTER_MAX * 2 &&
+ sc.nr_scanned > sc.nr_reclaimed + sc.nr_reclaimed / 2)
sc.may_writepage = 1;

- if (nr_pages && to_free > total_reclaimed)
+ if (nr_pages && to_free > sc.nr_reclaimed)
continue; /* swsusp: need to do more work */
if (all_zones_ok)
break; /* kswapd: all done */
@@ -1457,7 +1449,7 @@ scan_swspd:
* OK, kswapd is getting into trouble. Take a nap, then take
* another pass across the zones.
*/
- if (total_scanned && priority < DEF_PRIORITY - PRIORITY_STEPS)
+ if (priority < DEF_PRIORITY - PRIORITY_STEPS)
blk_congestion_wait(WRITE, HZ/10);

/*
@@ -1466,7 +1458,7 @@ scan_swspd:
* matches the direct reclaim path behaviour in terms of impact
* on zone->*_priority.
*/
- if ((total_reclaimed >= SWAP_CLUSTER_MAX) && (!nr_pages))
+ if (sc.nr_reclaimed >= SWAP_CLUSTER_MAX && !nr_pages)
break;
}
for (i = 0; i < pgdat->nr_zones; i++) {
@@ -1479,7 +1471,7 @@ scan_swspd:
goto loop_again;
}

- return total_reclaimed;
+ return sc.nr_reclaimed;
}

/*

--
-
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