- Don't need to show zone->unreclaimable in sysrq-M output: -mm has
/proc/zoneinfo.
- `foo = ATOMIC_INIT()' doesn't compile. Use atomic_set().
- Use jiffies, not get_jiffies_64(). The latter returns u64.
- Add comments (dammit)
- s/ALL_UNRECL/ALL_UNRECLAIMABLE/
- Don't assume that HZ = ~1000.
Cc: Martin Hicks <mort@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
include/linux/mmzone.h | 13 ++++++-------
mm/page_alloc.c | 12 +++++-------
mm/vmscan.c | 45 +++++++++++++++++++++++++++------------------
3 files changed, 38 insertions(+), 32 deletions(-)
diff -puN include/linux/mmzone.h~vm-page-cache-reclaim-core-tidy include/linux/mmzone.h
--- 25/include/linux/mmzone.h~vm-page-cache-reclaim-core-tidy 2005-05-09 20:09:15.000000000 -0700
+++ 25-akpm/include/linux/mmzone.h 2005-05-09 20:09:15.000000000 -0700
@@ -29,13 +29,12 @@ struct free_area {
struct pglist_data;
/*
- * Information about reclaimability of a zone's pages.
- * After we have scanned a zone and determined that there
- * are no other pages to free of a certain type we can
- * stop scanning it
+ * Information about reclaimability of a zone's pages, in zone->unreclaimable.
+ * After we have scanned a zone and determined that there are no other pages to
+ * free of a certain type we can stop scanning it.
*/
-#define CLEAN_UNRECL 0x1
-#define ALL_UNRECL 0x3
+#define CLEAN_UNRECLAIMABLE 0x1 /* No reclaimable clean pages */
+#define ALL_UNRECLAIMABLE 0x3 /* No reclaimable pages at all */
/*
* zone->lock and zone->lru_lock are two of the hottest locks in the kernel.
@@ -152,7 +151,7 @@ struct zone {
unsigned long nr_inactive;
unsigned long pages_scanned; /* since last reclaim */
int unreclaimable; /* pinned pages marker */
- atomic_t reclaim_count;
+ atomic_t reclaim_count; /* concurrency counter */
unsigned long reclaim_timeout;
/*
diff -puN mm/vmscan.c~vm-page-cache-reclaim-core-tidy mm/vmscan.c
--- 25/mm/vmscan.c~vm-page-cache-reclaim-core-tidy 2005-05-09 20:09:15.000000000 -0700
+++ 25-akpm/mm/vmscan.c 2005-05-09 20:09:15.000000000 -0700
@@ -717,6 +717,9 @@ static void shrink_cache(struct zone *zo
*
* The downside is that we have to touch page->_count against each page.
* But we had to alter page->flags anyway.
+ *
+ * Returns the number of pages which were moved from the active list to the
+ * inactive list.
*/
static int
refill_inactive_zone(struct zone *zone, struct scan_control *sc)
@@ -933,7 +936,7 @@ shrink_caches(struct zone **zones, struc
if (zone->prev_priority > sc->priority)
zone->prev_priority = sc->priority;
- if (zone->unreclaimable == ALL_UNRECL &&
+ if (zone->unreclaimable == ALL_UNRECLAIMABLE &&
sc->priority != DEF_PRIORITY)
continue; /* Let kswapd poll it */
@@ -1098,7 +1101,7 @@ loop_again:
if (zone->present_pages == 0)
continue;
- if (zone->unreclaimable == ALL_UNRECL &&
+ if (zone->unreclaimable == ALL_UNRECLAIMABLE &&
priority != DEF_PRIORITY)
continue;
@@ -1135,7 +1138,7 @@ scan:
if (zone->present_pages == 0)
continue;
- if (zone->unreclaimable == ALL_UNRECL &&
+ if (zone->unreclaimable == ALL_UNRECLAIMABLE &&
priority != DEF_PRIORITY)
continue;
@@ -1158,11 +1161,11 @@ scan:
sc.nr_reclaimed += reclaim_state->reclaimed_slab;
total_reclaimed += sc.nr_reclaimed;
total_scanned += sc.nr_scanned;
- if (zone->unreclaimable == ALL_UNRECL)
+ if (zone->unreclaimable == ALL_UNRECLAIMABLE)
continue;
if (nr_slab == 0 && zone->pages_scanned >=
(zone->nr_active + zone->nr_inactive) * 4)
- zone->unreclaimable = ALL_UNRECL;
+ zone->unreclaimable = ALL_UNRECLAIMABLE;
/*
* If we've done a decent amount of scanning and
* the reclaim ratio is low, start doing writepage
@@ -1367,7 +1370,15 @@ module_init(kswapd_init)
/* How many pages are processed at a time. */
#define MIN_RECLAIM 32
#define MAX_BATCH_SIZE 128
-#define UNRECLAIMABLE_TIMEOUT 5
+
+/*
+ * Rate-limit the period between automatic clean page reclaim attempts to this
+ * many jiffies.
+ */
+#define UNRECLAIMABLE_TIMEOUT_MSECS 5
+#define UNRECLAIMABLE_TIMEOUT_JIFS ((UNRECLAIMABLE_TIMEOUT_MSECS * HZ) / 1000)
+#define UNRECLAIMABLE_TIMEOUT \
+ (UNRECLAIMABLE_TIMEOUT_JIFS ? UNRECLAIMABLE_TIMEOUT_JIFS : 1)
unsigned int reclaim_clean_pages(struct zone *zone, long pages, int flags)
{
@@ -1379,15 +1390,14 @@ unsigned int reclaim_clean_pages(struct
int manual = flags & RECLAIM_MANUAL;
/* Zone is marked dead */
- if (zone->unreclaimable & CLEAN_UNRECL && !manual)
+ if ((zone->unreclaimable & CLEAN_UNRECLAIMABLE) && !manual)
return 0;
/* We don't really want to call this too often */
- if (get_jiffies_64() < zone->reclaim_timeout) {
+ if (time_before(jiffies, zone->reclaim_timeout)) {
/* check for jiffies overflow -- needed? */
- if (zone->reclaim_timeout - get_jiffies_64() >
- UNRECLAIMABLE_TIMEOUT)
- zone->reclaim_timeout = get_jiffies_64();
+ if (zone->reclaim_timeout - jiffies > UNRECLAIMABLE_TIMEOUT)
+ zone->reclaim_timeout = jiffies;
else if (!manual)
return 0;
}
@@ -1411,9 +1421,8 @@ unsigned int reclaim_clean_pages(struct
pages = MIN_RECLAIM;
/*
- * Also don't take too many pages at a time,
- * which can lead to a big overshoot in the
- * number of pages that are freed.
+ * Also don't take too many pages at a time, which can lead to a big
+ * overshoot in the number of pages that are freed.
*/
if (pages > MAX_BATCH_SIZE)
batch_size = MAX_BATCH_SIZE;
@@ -1454,7 +1463,8 @@ unsigned int reclaim_clean_pages(struct
}
if (flags & (RECLAIM_ACTIVE_UNMAPPED | RECLAIM_ACTIVE_MAPPED)) {
- /* Get flags for scan_control again, in case they were
+ /*
+ * Get flags for scan_control again, in case they were
* cleared while doing inactive reclaim
*/
sc.reclaim_flags = flags;
@@ -1487,9 +1497,8 @@ unsigned int reclaim_clean_pages(struct
/* The goal wasn't met */
if (pages > 0) {
- zone->reclaim_timeout = get_jiffies_64() +
- UNRECLAIMABLE_TIMEOUT;
- zone->unreclaimable |= CLEAN_UNRECL;
+ zone->reclaim_timeout = jiffies + UNRECLAIMABLE_TIMEOUT;
+ zone->unreclaimable |= CLEAN_UNRECLAIMABLE;
}
atomic_set(&zone->reclaim_count, -1);
diff -puN mm/page_alloc.c~vm-page-cache-reclaim-core-tidy mm/page_alloc.c
--- 25/mm/page_alloc.c~vm-page-cache-reclaim-core-tidy 2005-05-09 20:09:15.000000000 -0700
+++ 25-akpm/mm/page_alloc.c 2005-05-09 20:09:15.000000000 -0700
@@ -1281,7 +1281,6 @@ void show_free_areas(void)
" inactive:%lukB"
" present:%lukB"
" pages_scanned:%lu"
- " unreclaimable: %d"
"\n",
zone->name,
K(zone->free_pages),
@@ -1291,8 +1290,7 @@ void show_free_areas(void)
K(zone->nr_active),
K(zone->nr_inactive),
K(zone->present_pages),
- zone->pages_scanned,
- zone->unreclaimable
+ zone->pages_scanned
);
printk("lowmem_reserve[]:");
for (i = 0; i < MAX_NR_ZONES; i++)
@@ -1732,8 +1730,8 @@ static void __init free_area_init_core(s
zone->nr_scan_inactive = 0;
zone->nr_active = 0;
zone->nr_inactive = 0;
- zone->reclaim_count = ATOMIC_INIT(-1);
- zone->reclaim_timeout = get_jiffies_64();
+ atomic_set(&zone->reclaim_count, -1);
+ zone->reclaim_timeout = jiffies;
if (!size)
continue;
@@ -1969,11 +1967,11 @@ static int zoneinfo_show(struct seq_file
#endif
}
seq_printf(m,
- "\n all_unreclaimable: %u"
+ "\n unreclaimable: %u"
"\n prev_priority: %i"
"\n temp_priority: %i"
"\n start_pfn: %lu",
- zone->all_unreclaimable,
+ zone->unreclaimable,
zone->prev_priority,
zone->temp_priority,
zone->zone_start_pfn);
_