[RFC][PATCH 3/4] vm-no-reclaim_mapped
From: Nick Piggin
Date: Tue Mar 09 2004 - 00:44:00 EST
Kill reclaim_mapped and its merry men.
linux-2.6-npiggin/include/linux/mmzone.h | 19 -------
linux-2.6-npiggin/mm/page_alloc.c | 2
linux-2.6-npiggin/mm/vmscan.c | 76 +++----------------------------
3 files changed, 8 insertions(+), 89 deletions(-)
diff -puN mm/vmscan.c~vm-no-reclaim_mapped mm/vmscan.c
--- linux-2.6/mm/vmscan.c~vm-no-reclaim_mapped 2004-03-09 14:05:03.000000000 +1100
+++ linux-2.6-npiggin/mm/vmscan.c 2004-03-09 16:31:21.000000000 +1100
@@ -590,10 +590,6 @@ static void shrink_active_list(struct zo
LIST_HEAD(l_active); /* Pages to go onto the active_list */
struct page *page;
struct pagevec pvec;
- int reclaim_mapped = 0;
- long mapped_ratio;
- long distress;
- long swap_tendency;
lru_add_drain();
pgmoved = 0;
@@ -618,59 +614,23 @@ static void shrink_active_list(struct zo
zone->nr_active -= pgmoved;
spin_unlock_irq(&zone->lru_lock);
- /*
- * `distress' is a measure of how much trouble we're having reclaiming
- * pages. 0 -> no problems. 100 -> great trouble.
- */
- distress = 100 >> zone->prev_priority;
-
- /*
- * The point of this algorithm is to decide when to start reclaiming
- * mapped memory instead of just pagecache. Work out how much memory
- * is mapped.
- */
- mapped_ratio = (ps->nr_mapped * 100) / total_memory;
-
- /*
- * Now decide how much we really want to unmap some pages. The mapped
- * ratio is downgraded - just because there's a lot of mapped memory
- * doesn't necessarily mean that page reclaim isn't succeeding.
- *
- * The distress ratio is important - we don't want to start going oom.
- *
- * A 100% value of vm_swappiness overrides this algorithm altogether.
- */
- swap_tendency = mapped_ratio / 2 + distress + vm_swappiness;
-
- /*
- * Now use this metric to decide whether to start moving mapped memory
- * onto the inactive list.
- */
- if (swap_tendency >= 100)
- reclaim_mapped = 1;
-
while (!list_empty(&l_hold)) {
page = lru_to_page(&l_hold);
list_del(&page->lru);
- if (page_mapped(page)) {
- if (!reclaim_mapped) {
- list_add(&page->lru, &l_active);
- continue;
- }
- pte_chain_lock(page);
- if (page_referenced(page)) {
- pte_chain_unlock(page);
- list_add(&page->lru, &l_active);
- continue;
- }
+ pte_chain_lock(page);
+ if (page_referenced(page)) {
pte_chain_unlock(page);
+ list_add(&page->lru, &l_active);
+ continue;
}
+ pte_chain_unlock(page);
+
/*
* FIXME: need to consider page_count(page) here if/when we
* reap orphaned pages via the LRU (Daniel's locking stuff)
*/
- if (total_swap_pages == 0 && !page->mapping &&
- !PagePrivate(page)) {
+ if (unlikely(total_swap_pages == 0 && !page->mapping &&
+ !PagePrivate(page))) {
list_add(&page->lru, &l_active);
continue;
}
@@ -800,9 +760,6 @@ shrink_caches(struct zone **zones, int p
struct zone *zone = zones[i];
int max_scan;
- if (zone->free_pages < zone->pages_high)
- zone->temp_priority = priority;
-
if (zone->all_unreclaimable && priority != DEF_PRIORITY)
continue; /* Let kswapd poll it */
@@ -840,9 +797,6 @@ int try_to_free_pages(struct zone **zone
inc_page_state(allocstall);
- for (i = 0; zones[i] != 0; i++)
- zones[i]->temp_priority = DEF_PRIORITY;
-
for (priority = DEF_PRIORITY; priority >= 0; priority--) {
int total_scanned = 0;
struct page_state ps;
@@ -875,8 +829,6 @@ int try_to_free_pages(struct zone **zone
if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY))
out_of_memory();
out:
- for (i = 0; zones[i] != 0; i++)
- zones[i]->prev_priority = zones[i]->temp_priority;
return ret;
}
@@ -914,12 +866,6 @@ static int balance_pgdat(pg_data_t *pgda
inc_page_state(pageoutrun);
- for (i = 0; i < pgdat->nr_zones; i++) {
- struct zone *zone = pgdat->node_zones + i;
-
- zone->temp_priority = DEF_PRIORITY;
- }
-
for (priority = DEF_PRIORITY; priority; priority--) {
int all_zones_ok = 1;
int pages_scanned = 0;
@@ -970,7 +916,6 @@ scan:
if (zone->free_pages <= zone->pages_high)
all_zones_ok = 0;
}
- zone->temp_priority = priority;
max_scan = zone->nr_inactive >> priority;
reclaimed = shrink_zone(zone, max_scan, GFP_KERNEL,
&total_scanned, ps);
@@ -996,11 +941,6 @@ scan:
blk_congestion_wait(WRITE, HZ/10);
}
out:
- for (i = 0; i < pgdat->nr_zones; i++) {
- struct zone *zone = pgdat->node_zones + i;
-
- zone->prev_priority = zone->temp_priority;
- }
return nr_pages - to_free;
}
diff -puN include/linux/mmzone.h~vm-no-reclaim_mapped include/linux/mmzone.h
--- linux-2.6/include/linux/mmzone.h~vm-no-reclaim_mapped 2004-03-09 14:14:39.000000000 +1100
+++ linux-2.6-npiggin/include/linux/mmzone.h 2004-03-09 16:31:21.000000000 +1100
@@ -86,25 +86,6 @@ struct zone {
ZONE_PADDING(_pad2_)
/*
- * prev_priority holds the scanning priority for this zone. It is
- * defined as the scanning priority at which we achieved our reclaim
- * target at the previous try_to_free_pages() or balance_pgdat()
- * invokation.
- *
- * We use prev_priority as a measure of how much stress page reclaim is
- * under - it drives the swappiness decision: whether to unmap mapped
- * pages.
- *
- * temp_priority is used to remember the scanning priority at which
- * this zone was successfully refilled to free_pages == pages_high.
- *
- * Access to both these fields is quite racy even on uniprocessor. But
- * it is expected to average out OK.
- */
- int temp_priority;
- int prev_priority;
-
- /*
* free areas of different sizes
*/
struct free_area free_area[MAX_ORDER];
diff -puN mm/page_alloc.c~vm-no-reclaim_mapped mm/page_alloc.c
--- linux-2.6/mm/page_alloc.c~vm-no-reclaim_mapped 2004-03-09 14:15:00.000000000 +1100
+++ linux-2.6-npiggin/mm/page_alloc.c 2004-03-09 16:31:21.000000000 +1100
@@ -1408,8 +1408,6 @@ static void __init free_area_init_core(s
zone->zone_pgdat = pgdat;
zone->free_pages = 0;
- zone->temp_priority = zone->prev_priority = DEF_PRIORITY;
-
/*
* The per-cpu-pages pools are set to around 1000th of the
* size of the zone. But no more than 1/4 of a meg - there's
_