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vmscan: simplify shrink_inactive_list()
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Now, max_scan of shrink_inactive_list() is always passed less than
SWAP_CLUSTER_MAX.  then, we can remove scanning pages loop in it.  This
patch also help stack diet.

detail
 - remove "while (nr_scanned < max_scan)" loop
 - remove nr_freed (now, we use nr_reclaimed directly)
 - remove nr_scan (now, we use nr_scanned directly)
 - rename max_scan to nr_to_scan
 - pass nr_to_scan into isolate_pages() directly instead
   using SWAP_CLUSTER_MAX

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michael Rubin <mrubin@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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KOSAKI Motohiro authored and Linus Torvalds committed Aug 10, 2010
1 parent 25edde0 commit e247dbc
Showing 1 changed file with 102 additions and 110 deletions.
212 changes: 102 additions & 110 deletions mm/vmscan.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1136,15 +1136,21 @@ static int too_many_isolated(struct zone *zone, int file,
* shrink_inactive_list() is a helper for shrink_zone(). It returns the number
* of reclaimed pages
*/
static unsigned long shrink_inactive_list(unsigned long max_scan,
static unsigned long shrink_inactive_list(unsigned long nr_to_scan,
struct zone *zone, struct scan_control *sc,
int priority, int file)
{
LIST_HEAD(page_list);
struct pagevec pvec;
unsigned long nr_scanned = 0;
unsigned long nr_scanned;
unsigned long nr_reclaimed = 0;
struct zone_reclaim_stat *reclaim_stat = get_reclaim_stat(zone, sc);
struct page *page;
unsigned long nr_taken;
unsigned long nr_active;
unsigned int count[NR_LRU_LISTS] = { 0, };
unsigned long nr_anon;
unsigned long nr_file;

while (unlikely(too_many_isolated(zone, file, sc))) {
congestion_wait(BLK_RW_ASYNC, HZ/10);
Expand All @@ -1159,129 +1165,115 @@ static unsigned long shrink_inactive_list(unsigned long max_scan,

lru_add_drain();
spin_lock_irq(&zone->lru_lock);
do {
struct page *page;
unsigned long nr_taken;
unsigned long nr_scan;
unsigned long nr_freed;
unsigned long nr_active;
unsigned int count[NR_LRU_LISTS] = { 0, };
int mode = sc->lumpy_reclaim_mode ? ISOLATE_BOTH : ISOLATE_INACTIVE;
unsigned long nr_anon;
unsigned long nr_file;

if (scanning_global_lru(sc)) {
nr_taken = isolate_pages_global(SWAP_CLUSTER_MAX,
&page_list, &nr_scan,
sc->order, mode,
zone, 0, file);
zone->pages_scanned += nr_scan;
if (current_is_kswapd())
__count_zone_vm_events(PGSCAN_KSWAPD, zone,
nr_scan);
else
__count_zone_vm_events(PGSCAN_DIRECT, zone,
nr_scan);
} else {
nr_taken = mem_cgroup_isolate_pages(SWAP_CLUSTER_MAX,
&page_list, &nr_scan,
sc->order, mode,
zone, sc->mem_cgroup,
0, file);
/*
* mem_cgroup_isolate_pages() keeps track of
* scanned pages on its own.
*/
}
if (scanning_global_lru(sc)) {
nr_taken = isolate_pages_global(nr_to_scan,
&page_list, &nr_scanned, sc->order,
sc->lumpy_reclaim_mode ?
ISOLATE_BOTH : ISOLATE_INACTIVE,
zone, 0, file);
zone->pages_scanned += nr_scanned;
if (current_is_kswapd())
__count_zone_vm_events(PGSCAN_KSWAPD, zone,
nr_scanned);
else
__count_zone_vm_events(PGSCAN_DIRECT, zone,
nr_scanned);
} else {
nr_taken = mem_cgroup_isolate_pages(nr_to_scan,
&page_list, &nr_scanned, sc->order,
sc->lumpy_reclaim_mode ?
ISOLATE_BOTH : ISOLATE_INACTIVE,
zone, sc->mem_cgroup,
0, file);
/*
* mem_cgroup_isolate_pages() keeps track of
* scanned pages on its own.
*/
}

if (nr_taken == 0)
goto done;
if (nr_taken == 0)
goto done;

nr_active = clear_active_flags(&page_list, count);
__count_vm_events(PGDEACTIVATE, nr_active);
nr_active = clear_active_flags(&page_list, count);
__count_vm_events(PGDEACTIVATE, nr_active);

__mod_zone_page_state(zone, NR_ACTIVE_FILE,
-count[LRU_ACTIVE_FILE]);
__mod_zone_page_state(zone, NR_INACTIVE_FILE,
-count[LRU_INACTIVE_FILE]);
__mod_zone_page_state(zone, NR_ACTIVE_ANON,
-count[LRU_ACTIVE_ANON]);
__mod_zone_page_state(zone, NR_INACTIVE_ANON,
-count[LRU_INACTIVE_ANON]);
__mod_zone_page_state(zone, NR_ACTIVE_FILE,
-count[LRU_ACTIVE_FILE]);
__mod_zone_page_state(zone, NR_INACTIVE_FILE,
-count[LRU_INACTIVE_FILE]);
__mod_zone_page_state(zone, NR_ACTIVE_ANON,
-count[LRU_ACTIVE_ANON]);
__mod_zone_page_state(zone, NR_INACTIVE_ANON,
-count[LRU_INACTIVE_ANON]);

nr_anon = count[LRU_ACTIVE_ANON] + count[LRU_INACTIVE_ANON];
nr_file = count[LRU_ACTIVE_FILE] + count[LRU_INACTIVE_FILE];
__mod_zone_page_state(zone, NR_ISOLATED_ANON, nr_anon);
__mod_zone_page_state(zone, NR_ISOLATED_FILE, nr_file);
nr_anon = count[LRU_ACTIVE_ANON] + count[LRU_INACTIVE_ANON];
nr_file = count[LRU_ACTIVE_FILE] + count[LRU_INACTIVE_FILE];
__mod_zone_page_state(zone, NR_ISOLATED_ANON, nr_anon);
__mod_zone_page_state(zone, NR_ISOLATED_FILE, nr_file);

reclaim_stat->recent_scanned[0] += nr_anon;
reclaim_stat->recent_scanned[1] += nr_file;
reclaim_stat->recent_scanned[0] += nr_anon;
reclaim_stat->recent_scanned[1] += nr_file;

spin_unlock_irq(&zone->lru_lock);
spin_unlock_irq(&zone->lru_lock);

nr_scanned += nr_scan;
nr_freed = shrink_page_list(&page_list, sc, PAGEOUT_IO_ASYNC);
nr_reclaimed = shrink_page_list(&page_list, sc, PAGEOUT_IO_ASYNC);

/*
* If we are direct reclaiming for contiguous pages and we do
* not reclaim everything in the list, try again and wait
* for IO to complete. This will stall high-order allocations
* but that should be acceptable to the caller
*/
if (nr_reclaimed < nr_taken && !current_is_kswapd() &&
sc->lumpy_reclaim_mode) {
congestion_wait(BLK_RW_ASYNC, HZ/10);

/*
* If we are direct reclaiming for contiguous pages and we do
* not reclaim everything in the list, try again and wait
* for IO to complete. This will stall high-order allocations
* but that should be acceptable to the caller
* The attempt at page out may have made some
* of the pages active, mark them inactive again.
*/
if (nr_freed < nr_taken && !current_is_kswapd() &&
sc->lumpy_reclaim_mode) {
congestion_wait(BLK_RW_ASYNC, HZ/10);

/*
* The attempt at page out may have made some
* of the pages active, mark them inactive again.
*/
nr_active = clear_active_flags(&page_list, count);
count_vm_events(PGDEACTIVATE, nr_active);

nr_freed += shrink_page_list(&page_list, sc,
PAGEOUT_IO_SYNC);
}
nr_active = clear_active_flags(&page_list, count);
count_vm_events(PGDEACTIVATE, nr_active);

nr_reclaimed += nr_freed;
nr_reclaimed += shrink_page_list(&page_list, sc, PAGEOUT_IO_SYNC);
}

local_irq_disable();
if (current_is_kswapd())
__count_vm_events(KSWAPD_STEAL, nr_freed);
__count_zone_vm_events(PGSTEAL, zone, nr_freed);
local_irq_disable();
if (current_is_kswapd())
__count_vm_events(KSWAPD_STEAL, nr_reclaimed);
__count_zone_vm_events(PGSTEAL, zone, nr_reclaimed);

spin_lock(&zone->lru_lock);
/*
* Put back any unfreeable pages.
*/
while (!list_empty(&page_list)) {
int lru;
page = lru_to_page(&page_list);
VM_BUG_ON(PageLRU(page));
list_del(&page->lru);
if (unlikely(!page_evictable(page, NULL))) {
spin_unlock_irq(&zone->lru_lock);
putback_lru_page(page);
spin_lock_irq(&zone->lru_lock);
continue;
}
SetPageLRU(page);
lru = page_lru(page);
add_page_to_lru_list(zone, page, lru);
if (is_active_lru(lru)) {
int file = is_file_lru(lru);
reclaim_stat->recent_rotated[file]++;
}
if (!pagevec_add(&pvec, page)) {
spin_unlock_irq(&zone->lru_lock);
__pagevec_release(&pvec);
spin_lock_irq(&zone->lru_lock);
}
spin_lock(&zone->lru_lock);
/*
* Put back any unfreeable pages.
*/
while (!list_empty(&page_list)) {
int lru;
page = lru_to_page(&page_list);
VM_BUG_ON(PageLRU(page));
list_del(&page->lru);
if (unlikely(!page_evictable(page, NULL))) {
spin_unlock_irq(&zone->lru_lock);
putback_lru_page(page);
spin_lock_irq(&zone->lru_lock);
continue;
}
__mod_zone_page_state(zone, NR_ISOLATED_ANON, -nr_anon);
__mod_zone_page_state(zone, NR_ISOLATED_FILE, -nr_file);

} while (nr_scanned < max_scan);
SetPageLRU(page);
lru = page_lru(page);
add_page_to_lru_list(zone, page, lru);
if (is_active_lru(lru)) {
int file = is_file_lru(lru);
reclaim_stat->recent_rotated[file]++;
}
if (!pagevec_add(&pvec, page)) {
spin_unlock_irq(&zone->lru_lock);
__pagevec_release(&pvec);
spin_lock_irq(&zone->lru_lock);
}
}
__mod_zone_page_state(zone, NR_ISOLATED_ANON, -nr_anon);
__mod_zone_page_state(zone, NR_ISOLATED_FILE, -nr_file);

done:
spin_unlock_irq(&zone->lru_lock);
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