Re: [patch 06/21] split LRU lists into anon & file sets

KOSAKI Motohiro
2008-03-01T12:14:29Z

Hi

>@@ -1128,64 +1026,65 @@ static void shrink_active_list(unsigned
(snip)
> + /*
> + * For sorting active vs inactive pages, we'll use the 'anon'
> + * elements of the local list[] array and sort out the file vs
> + * anon pages below.
> + */

IMHO this comment implies code is not so good...

I think shrink_active_list should not change to indexed array.
because this function almost use no indexed array operation.

the following is only explain my intention patch.

---
mm/vmscan.c | 29 +++++++++++------------------
1 file changed, 11 insertions(+), 18 deletions(-)

Index: b/mm/vmscan.c
===================================================================
--- a/mm/vmscan.c 2008-03-01 21:11:03.000000000 +0900
+++ b/mm/vmscan.c 2008-03-01 21:13:13.000000000 +0900
@@ -1023,14 +1023,12 @@ static void shrink_active_list(unsigned
int pgdeactivate = 0;
unsigned long pgscanned;
LIST_HEAD(l_hold); /* The pages which were snipped off */
- struct list_head list[NR_LRU_LISTS];
+ LIST_HEAD(l_active);
+ LIST_HEAD(l_inactive);
struct page *page;
struct pagevec pvec;
enum lru_list lru;

- for_each_lru(lru)
- INIT_LIST_HEAD(&list[lru]);
-
lru_add_drain();
spin_lock_irq(&zone->lru_lock);
pgmoved = sc->isolate_pages(nr_pages, &l_hold, &pgscanned, sc->order,
@@ -1048,19 +1046,14 @@ static void shrink_active_list(unsigned
__mod_zone_page_state(zone, NR_ACTIVE_ANON, -pgmoved);
spin_unlock_irq(&zone->lru_lock);

- /*
- * For sorting active vs inactive pages, we'll use the 'anon'
- * elements of the local list[] array and sort out the file vs
- * anon pages below.
- */
while (!list_empty(&l_hold)) {
- lru = LRU_INACTIVE_ANON;
cond_resched();
page = lru_to_page(&l_hold);
list_del(&page->lru);
if (page_referenced(page, 0, sc->mem_cgroup))
- lru = LRU_ACTIVE_ANON;
- list_add(&page->lru, &list[lru]);
+ list_add(&page->lru, &l_active);
+ else
+ list_add(&page->lru, &l_inactive);
}

/*
@@ -1071,9 +1064,9 @@ static void shrink_active_list(unsigned
pgmoved = 0;
lru = LRU_BASE + file * LRU_FILE;
spin_lock_irq(&zone->lru_lock);
- while (!list_empty(&list[LRU_INACTIVE_ANON])) {
- page = lru_to_page(&list[LRU_INACTIVE_ANON]);
- prefetchw_prev_lru_page(page, &list[LRU_INACTIVE_ANON], flags);
+ while (!list_empty(&l_inactive)) {
+ page = lru_to_page(&l_inactive);
+ prefetchw_prev_lru_page(page, &l_inactive, flags);
VM_BUG_ON(PageLRU(page));
SetPageLRU(page);
VM_BUG_ON(!PageActive(page));
@@ -1104,9 +1097,9 @@ static void shrink_active_list(unsigned

pgmoved = 0;
lru = LRU_ACTIVE + file * LRU_FILE;
- while (!list_empty(&list[LRU_ACTIVE_ANON])) {
- page = lru_to_page(&list[LRU_ACTIVE_ANON]);
- prefetchw_prev_lru_page(page, &list[LRU_ACTIVE_ANON], flags);
+ while (!list_empty(&l_active)) {
+ page = lru_to_page(&l_active);
+ prefetchw_prev_lru_page(page, &l_active, flags);
VM_BUG_ON(PageLRU(page));
SetPageLRU(page);
VM_BUG_ON(!PageActive(page));