From: Nick Piggin <nickpiggin@yahoo.com.au>
Replace lots of parameters to functions in mm/vmscan.c with a structure
struct scan_control.
Signed-off-by: Nick Piggin <nickpiggin@cyberone.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/mm/vmscan.c | 203 ++++++++++++++++++++++++++--------------------------
1 files changed, 102 insertions(+), 101 deletions(-)
diff -puN mm/vmscan.c~vmscanc-struct-scan_control mm/vmscan.c
--- 25/mm/vmscan.c~vmscanc-struct-scan_control 2004-05-31 21:02:04.756658984 -0700
+++ 25-akpm/mm/vmscan.c 2004-05-31 21:02:04.763657920 -0700
@@ -310,17 +310,35 @@ static pageout_t pageout(struct page *pa
return PAGE_CLEAN;
}
+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;
+
+ /* Incremented by the number of pages reclaimed */
+ unsigned long nr_reclaimed;
+
+ /* Ask shrink_caches, or shrink_zone to scan at this priority */
+ unsigned int priority;
+
+ /* This context's GFP mask */
+ unsigned int gfp_mask;
+
+ struct page_state ps;
+ int may_writepage;
+};
+
/*
- * shrink_list returns the number of reclaimed pages
+ * shrink_list adds the number of reclaimed pages to sc->nr_reclaimed
*/
-static int
-shrink_list(struct list_head *page_list, unsigned int gfp_mask,
- int *nr_scanned, int do_writepage)
+static int shrink_list(struct list_head *page_list, struct scan_control *sc)
{
LIST_HEAD(ret_pages);
struct pagevec freed_pvec;
int pgactivate = 0;
- int ret = 0;
+ int reclaimed = 0;
cond_resched();
@@ -337,15 +355,16 @@ shrink_list(struct list_head *page_list,
if (TestSetPageLocked(page))
goto keep;
- /* Double the slab pressure for mapped and swapcache pages */
- if (page_mapped(page) || PageSwapCache(page))
- (*nr_scanned)++;
-
BUG_ON(PageActive(page));
if (PageWriteback(page))
goto keep_locked;
+ sc->nr_scanned++;
+ /* Double the slab pressure for mapped and swapcache pages */
+ if (page_mapped(page) || PageSwapCache(page))
+ sc->nr_scanned++;
+
page_map_lock(page);
referenced = page_referenced(page);
if (referenced && page_mapping_inuse(page)) {
@@ -370,8 +389,8 @@ shrink_list(struct list_head *page_list,
#endif /* CONFIG_SWAP */
mapping = page_mapping(page);
- may_enter_fs = (gfp_mask & __GFP_FS) ||
- (PageSwapCache(page) && (gfp_mask & __GFP_IO));
+ may_enter_fs = (sc->gfp_mask & __GFP_FS) ||
+ (PageSwapCache(page) && (sc->gfp_mask & __GFP_IO));
/*
* The page is mapped into the page tables of one or more
@@ -396,7 +415,7 @@ shrink_list(struct list_head *page_list,
goto keep_locked;
if (!may_enter_fs)
goto keep_locked;
- if (laptop_mode && !do_writepage)
+ if (laptop_mode && !sc->may_writepage)
goto keep_locked;
/* Page is dirty, try to write it out here */
@@ -444,7 +463,7 @@ shrink_list(struct list_head *page_list,
* Otherwise, leave the page on the LRU so it is swappable.
*/
if (PagePrivate(page)) {
- if (!try_to_release_page(page, gfp_mask))
+ if (!try_to_release_page(page, sc->gfp_mask))
goto activate_locked;
if (!mapping && page_count(page) == 1)
goto free_it;
@@ -482,7 +501,7 @@ shrink_list(struct list_head *page_list,
free_it:
unlock_page(page);
- ret++;
+ reclaimed++;
if (!pagevec_add(&freed_pvec, page))
__pagevec_release_nonlru(&freed_pvec);
continue;
@@ -500,7 +519,8 @@ keep:
if (pagevec_count(&freed_pvec))
__pagevec_release_nonlru(&freed_pvec);
mod_page_state(pgactivate, pgactivate);
- return ret;
+ sc->nr_reclaimed += reclaimed;
+ return reclaimed;
}
/*
@@ -508,19 +528,16 @@ keep:
* a batch of pages and working on them outside the lock. Any pages which were
* not freed will be added back to the LRU.
*
- * shrink_cache() is passed the number of pages to scan and returns the number
- * of pages which were reclaimed.
+ * shrink_cache() adds the number of pages reclaimed to sc->nr_reclaimed
*
* For pagecache intensive workloads, the first loop here is the hottest spot
* in the kernel (apart from the copy_*_user functions).
*/
-static int
-shrink_cache(struct zone *zone, unsigned int gfp_mask,
- int max_scan, int *total_scanned, int do_writepage)
+static void shrink_cache(struct zone *zone, struct scan_control *sc)
{
LIST_HEAD(page_list);
struct pagevec pvec;
- int ret = 0;
+ int max_scan = sc->nr_to_scan;
pagevec_init(&pvec, 1);
@@ -566,17 +583,11 @@ shrink_cache(struct zone *zone, unsigned
mod_page_state_zone(zone, pgscan_kswapd, nr_scan);
else
mod_page_state_zone(zone, pgscan_direct, nr_scan);
- nr_freed = shrink_list(&page_list, gfp_mask,
- total_scanned, do_writepage);
- *total_scanned += nr_taken;
+ nr_freed = shrink_list(&page_list, sc);
if (current_is_kswapd())
mod_page_state(kswapd_steal, nr_freed);
mod_page_state_zone(zone, pgsteal, nr_freed);
- ret += nr_freed;
- if (nr_freed <= 0 && list_empty(&page_list))
- goto done;
-
spin_lock_irq(&zone->lru_lock);
/*
* Put back any unfreeable pages.
@@ -600,7 +611,6 @@ shrink_cache(struct zone *zone, unsigned
spin_unlock_irq(&zone->lru_lock);
done:
pagevec_release(&pvec);
- return ret;
}
/*
@@ -621,12 +631,12 @@ done:
* But we had to alter page->flags anyway.
*/
static void
-refill_inactive_zone(struct zone *zone, const int nr_pages_in,
- struct page_state *ps)
+refill_inactive_zone(struct zone *zone, struct scan_control *sc)
{
int pgmoved;
int pgdeactivate = 0;
- int nr_pages = nr_pages_in;
+ int pgscanned = 0;
+ 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 */
@@ -640,7 +650,7 @@ refill_inactive_zone(struct zone *zone,
lru_add_drain();
pgmoved = 0;
spin_lock_irq(&zone->lru_lock);
- while (nr_pages && !list_empty(&zone->active_list)) {
+ while (pgscanned < nr_pages && !list_empty(&zone->active_list)) {
page = lru_to_page(&zone->active_list);
prefetchw_prev_lru_page(page, &zone->active_list, flags);
if (!TestClearPageLRU(page))
@@ -660,7 +670,7 @@ refill_inactive_zone(struct zone *zone,
list_add(&page->lru, &l_hold);
pgmoved++;
}
- nr_pages--;
+ pgscanned++;
}
zone->nr_active -= pgmoved;
spin_unlock_irq(&zone->lru_lock);
@@ -676,7 +686,7 @@ refill_inactive_zone(struct zone *zone,
* mapped memory instead of just pagecache. Work out how much memory
* is mapped.
*/
- mapped_ratio = (ps->nr_mapped * 100) / total_memory;
+ mapped_ratio = (sc->ps.nr_mapped * 100) / total_memory;
/*
* Now decide how much we really want to unmap some pages. The mapped
@@ -775,7 +785,7 @@ refill_inactive_zone(struct zone *zone,
spin_unlock_irq(&zone->lru_lock);
pagevec_release(&pvec);
- mod_page_state_zone(zone, pgrefill, nr_pages_in - nr_pages);
+ mod_page_state_zone(zone, pgrefill, pgscanned);
mod_page_state(pgdeactivate, pgdeactivate);
}
@@ -783,13 +793,14 @@ refill_inactive_zone(struct zone *zone,
* Scan `nr_pages' from this zone. Returns the number of reclaimed pages.
* This is a basic per-zone page freer. Used by both kswapd and direct reclaim.
*/
-static int
-shrink_zone(struct zone *zone, int max_scan, unsigned int gfp_mask,
- int *total_scanned, struct page_state *ps, int do_writepage)
+static void
+shrink_zone(struct zone *zone, struct scan_control *sc)
{
- unsigned long scan_active;
+ unsigned long scan_active, scan_inactive;
int count;
+ scan_inactive = (zone->nr_active + zone->nr_inactive) >> sc->priority;
+
/*
* Try to keep the active list 2/3 of the size of the cache. And
* make sure that refill_inactive is given a decent number of pages.
@@ -802,13 +813,13 @@ shrink_zone(struct zone *zone, int max_s
*/
if (zone->nr_active >= 4*(zone->nr_inactive*2 + 1)) {
/* Don't scan more than 4 times the inactive list scan size */
- scan_active = 4*max_scan;
+ scan_active = 4*scan_inactive;
} else {
unsigned long long tmp;
/* Cast to long long so the multiply doesn't overflow */
- tmp = (unsigned long long)max_scan * zone->nr_active;
+ tmp = (unsigned long long)scan_inactive * zone->nr_active;
do_div(tmp, zone->nr_inactive*2 + 1);
scan_active = (unsigned long)tmp;
}
@@ -817,17 +828,17 @@ shrink_zone(struct zone *zone, int max_s
count = atomic_read(&zone->nr_scan_active);
if (count >= SWAP_CLUSTER_MAX) {
atomic_set(&zone->nr_scan_active, 0);
- refill_inactive_zone(zone, count, ps);
+ sc->nr_to_scan = count;
+ refill_inactive_zone(zone, sc);
}
- atomic_add(max_scan, &zone->nr_scan_inactive);
+ atomic_add(scan_inactive, &zone->nr_scan_inactive);
count = atomic_read(&zone->nr_scan_inactive);
if (count >= SWAP_CLUSTER_MAX) {
atomic_set(&zone->nr_scan_inactive, 0);
- return shrink_cache(zone, gfp_mask, count,
- total_scanned, do_writepage);
+ sc->nr_to_scan = count;
+ return shrink_cache(zone, sc);
}
- return 0;
}
/*
@@ -846,29 +857,23 @@ shrink_zone(struct zone *zone, int max_s
* If a zone is deemed to be full of pinned pages then just give it a light
* scan then give up on it.
*/
-static int
-shrink_caches(struct zone **zones, int priority, int *total_scanned,
- int gfp_mask, struct page_state *ps, int do_writepage)
+static void
+shrink_caches(struct zone **zones, struct scan_control *sc)
{
- int ret = 0;
int i;
for (i = 0; zones[i] != NULL; i++) {
struct zone *zone = zones[i];
- int max_scan;
- zone->temp_priority = priority;
- if (zone->prev_priority > priority)
- zone->prev_priority = priority;
+ zone->temp_priority = sc->priority;
+ if (zone->prev_priority > sc->priority)
+ zone->prev_priority = sc->priority;
- if (zone->all_unreclaimable && priority != DEF_PRIORITY)
+ if (zone->all_unreclaimable && sc->priority != DEF_PRIORITY)
continue; /* Let kswapd poll it */
- max_scan = (zone->nr_active + zone->nr_inactive) >> priority;
- ret += shrink_zone(zone, max_scan, gfp_mask,
- total_scanned, ps, do_writepage);
+ shrink_zone(zone, sc);
}
- return ret;
}
/*
@@ -889,11 +894,13 @@ int try_to_free_pages(struct zone **zone
{
int priority;
int ret = 0;
- int nr_reclaimed = 0;
+ int total_scanned = 0, total_reclaimed = 0;
struct reclaim_state *reclaim_state = current->reclaim_state;
+ struct scan_control sc;
int i;
- unsigned long total_scanned = 0;
- int do_writepage = 0;
+
+ sc.gfp_mask = gfp_mask;
+ sc.may_writepage = 0;
inc_page_state(allocstall);
@@ -901,21 +908,23 @@ int try_to_free_pages(struct zone **zone
zones[i]->temp_priority = DEF_PRIORITY;
for (priority = DEF_PRIORITY; priority >= 0; priority--) {
- int scanned = 0;
- struct page_state ps;
-
- get_page_state(&ps);
- nr_reclaimed += shrink_caches(zones, priority, &scanned,
- gfp_mask, &ps, do_writepage);
- shrink_slab(scanned, gfp_mask);
+ get_page_state(&sc.ps);
+ sc.nr_scanned = 0;
+ sc.nr_reclaimed = 0;
+ sc.priority = priority;
+ shrink_caches(zones, &sc);
+ shrink_slab(sc.nr_scanned, gfp_mask);
if (reclaim_state) {
- nr_reclaimed += reclaim_state->reclaimed_slab;
+ sc.nr_reclaimed += reclaim_state->reclaimed_slab;
reclaim_state->reclaimed_slab = 0;
}
- if (nr_reclaimed >= SWAP_CLUSTER_MAX) {
+ if (sc.nr_reclaimed >= SWAP_CLUSTER_MAX) {
ret = 1;
goto out;
}
+ total_scanned += sc.nr_scanned;
+ total_reclaimed += sc.nr_reclaimed;
+
/*
* Try to write back as many pages as we just scanned. This
* tends to cause slow streaming writers to write data to the
@@ -923,14 +932,13 @@ 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.
*/
- total_scanned += scanned;
if (total_scanned > SWAP_CLUSTER_MAX + SWAP_CLUSTER_MAX/2) {
wakeup_bdflush(laptop_mode ? 0 : total_scanned);
- do_writepage = 1;
+ sc.may_writepage = 1;
}
/* Take a nap, wait for some writeback to complete */
- if (scanned && priority < DEF_PRIORITY - 2)
+ if (sc.nr_scanned && priority < DEF_PRIORITY - 2)
blk_congestion_wait(WRITE, HZ/10);
}
if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY))
@@ -966,15 +974,18 @@ out:
* the page allocator fallback scheme to ensure that aging of pages is balanced
* across the zones.
*/
-static int balance_pgdat(pg_data_t *pgdat, int nr_pages, struct page_state *ps)
+static int balance_pgdat(pg_data_t *pgdat, int nr_pages)
{
int to_free = nr_pages;
int priority;
int i;
+ int total_scanned = 0, total_reclaimed = 0;
struct reclaim_state *reclaim_state = current->reclaim_state;
- unsigned long total_scanned = 0;
- unsigned long total_reclaimed = 0;
- int do_writepage = 0;
+ struct scan_control sc;
+
+ sc.gfp_mask = GFP_KERNEL;
+ sc.may_writepage = 0;
+ get_page_state(&sc.ps);
inc_page_state(pageoutrun);
@@ -1022,9 +1033,6 @@ scan:
*/
for (i = 0; i <= end_zone; i++) {
struct zone *zone = pgdat->node_zones + i;
- int max_scan;
- int reclaimed;
- int scanned = 0;
if (zone->all_unreclaimable && priority != DEF_PRIORITY)
continue;
@@ -1036,16 +1044,14 @@ scan:
zone->temp_priority = priority;
if (zone->prev_priority > priority)
zone->prev_priority = priority;
- max_scan = (zone->nr_active + zone->nr_inactive)
- >> priority;
- reclaimed = shrink_zone(zone, max_scan, GFP_KERNEL,
- &scanned, ps, do_writepage);
- total_scanned += scanned;
+ sc.nr_scanned = 0;
+ sc.nr_reclaimed = 0;
+ sc.priority = priority;
+ shrink_zone(zone, &sc);
reclaim_state->reclaimed_slab = 0;
- shrink_slab(scanned, GFP_KERNEL);
- reclaimed += reclaim_state->reclaimed_slab;
- total_reclaimed += reclaimed;
- to_free -= reclaimed;
+ shrink_slab(sc.nr_scanned, GFP_KERNEL);
+ sc.nr_reclaimed += reclaim_state->reclaimed_slab;
+ total_reclaimed += sc.nr_reclaimed;
if (zone->all_unreclaimable)
continue;
if (zone->pages_scanned > zone->present_pages * 2)
@@ -1057,9 +1063,9 @@ scan:
*/
if (total_scanned > SWAP_CLUSTER_MAX * 2 &&
total_scanned > total_reclaimed+total_reclaimed/2)
- do_writepage = 1;
+ sc.may_writepage = 1;
}
- if (nr_pages && to_free > 0)
+ if (nr_pages && to_free > total_reclaimed)
continue; /* swsusp: need to do more work */
if (all_zones_ok)
break; /* kswapd: all done */
@@ -1123,15 +1129,13 @@ int kswapd(void *p)
tsk->flags |= PF_MEMALLOC|PF_KSWAPD;
for ( ; ; ) {
- struct page_state ps;
-
if (current->flags & PF_FREEZE)
refrigerator(PF_FREEZE);
prepare_to_wait(&pgdat->kswapd_wait, &wait, TASK_INTERRUPTIBLE);
schedule();
finish_wait(&pgdat->kswapd_wait, &wait);
- get_page_state(&ps);
- balance_pgdat(pgdat, 0, &ps);
+
+ balance_pgdat(pgdat, 0);
}
}
@@ -1164,10 +1168,7 @@ int shrink_all_memory(int nr_pages)
current->reclaim_state = &reclaim_state;
for_each_pgdat(pgdat) {
int freed;
- struct page_state ps;
-
- get_page_state(&ps);
- freed = balance_pgdat(pgdat, nr_to_free, &ps);
+ freed = balance_pgdat(pgdat, nr_to_free);
ret += freed;
nr_to_free -= freed;
if (nr_to_free <= 0)
_