oom: change all_unreclaimable zone member to flags
Convert the int all_unreclaimable member of struct zone to unsigned long
flags. This can now be used to specify several different zone flags such as
all_unreclaimable and reclaim_in_progress, which can now be removed and
converted to a per-zone flag.
Flags are set and cleared as follows:
zone_set_flag(struct zone *zone, zone_flags_t flag)
zone_clear_flag(struct zone *zone, zone_flags_t flag)
Defines the first zone flags, ZONE_ALL_UNRECLAIMABLE and ZONE_RECLAIM_LOCKED,
which have the same semantics as the old zone->all_unreclaimable and
zone->reclaim_in_progress, respectively. Also converts all current users that
set or clear either flag to use the new interface.
Helper functions are defined to test the flags:
int zone_is_all_unreclaimable(const struct zone *zone)
int zone_is_reclaim_locked(const struct zone *zone)
All flag operators are of the atomic variety because there are currently
readers that are implemented that do not take zone->lock.
[akpm@linux-foundation.org: add needed include]
Cc: Andrea Arcangeli <andrea@suse.de>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index f4bfe82..bad9486 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -7,6 +7,7 @@
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/wait.h>
+#include <linux/bitops.h>
#include <linux/cache.h>
#include <linux/threads.h>
#include <linux/numa.h>
@@ -262,10 +263,7 @@
unsigned long nr_scan_active;
unsigned long nr_scan_inactive;
unsigned long pages_scanned; /* since last reclaim */
- int all_unreclaimable; /* All pages pinned */
-
- /* A count of how many reclaimers are scanning this zone */
- atomic_t reclaim_in_progress;
+ unsigned long flags; /* zone flags, see below */
/* Zone statistics */
atomic_long_t vm_stat[NR_VM_ZONE_STAT_ITEMS];
@@ -343,6 +341,29 @@
const char *name;
} ____cacheline_internodealigned_in_smp;
+typedef enum {
+ ZONE_ALL_UNRECLAIMABLE, /* all pages pinned */
+ ZONE_RECLAIM_LOCKED, /* prevents concurrent reclaim */
+} zone_flags_t;
+
+static inline void zone_set_flag(struct zone *zone, zone_flags_t flag)
+{
+ set_bit(flag, &zone->flags);
+}
+static inline void zone_clear_flag(struct zone *zone, zone_flags_t flag)
+{
+ clear_bit(flag, &zone->flags);
+}
+
+static inline int zone_is_all_unreclaimable(const struct zone *zone)
+{
+ return test_bit(ZONE_ALL_UNRECLAIMABLE, &zone->flags);
+}
+static inline int zone_is_reclaim_locked(const struct zone *zone)
+{
+ return test_bit(ZONE_RECLAIM_LOCKED, &zone->flags);
+}
+
/*
* The "priority" of VM scanning is how much of the queues we will scan in one
* go. A value of 12 for DEF_PRIORITY implies that we will scan 1/4096th of the
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0e3a05f..fd2df29 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -490,7 +490,7 @@
struct list_head *list, int order)
{
spin_lock(&zone->lock);
- zone->all_unreclaimable = 0;
+ zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE);
zone->pages_scanned = 0;
while (count--) {
struct page *page;
@@ -507,7 +507,7 @@
static void free_one_page(struct zone *zone, struct page *page, int order)
{
spin_lock(&zone->lock);
- zone->all_unreclaimable = 0;
+ zone_clear_flag(zone, ZONE_ALL_UNRECLAIMABLE);
zone->pages_scanned = 0;
__free_one_page(page, zone, order);
spin_unlock(&zone->lock);
@@ -1851,7 +1851,7 @@
K(zone_page_state(zone, NR_INACTIVE)),
K(zone->present_pages),
zone->pages_scanned,
- (zone->all_unreclaimable ? "yes" : "no")
+ (zone_is_all_unreclaimable(zone) ? "yes" : "no")
);
printk("lowmem_reserve[]:");
for (i = 0; i < MAX_NR_ZONES; i++)
@@ -3372,7 +3372,7 @@
zone->nr_scan_active = 0;
zone->nr_scan_inactive = 0;
zap_zone_vm_stats(zone);
- atomic_set(&zone->reclaim_in_progress, 0);
+ zone->flags = 0;
if (!size)
continue;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index bbd1946..d8893dc 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1108,7 +1108,7 @@
unsigned long nr_to_scan;
unsigned long nr_reclaimed = 0;
- atomic_inc(&zone->reclaim_in_progress);
+ zone_set_flag(zone, ZONE_RECLAIM_LOCKED);
/*
* Add one to `nr_to_scan' just to make sure that the kernel will
@@ -1149,7 +1149,7 @@
throttle_vm_writeout(sc->gfp_mask);
- atomic_dec(&zone->reclaim_in_progress);
+ zone_clear_flag(zone, ZONE_RECLAIM_LOCKED);
return nr_reclaimed;
}
@@ -1187,7 +1187,7 @@
note_zone_scanning_priority(zone, priority);
- if (zone->all_unreclaimable && priority != DEF_PRIORITY)
+ if (zone_is_all_unreclaimable(zone) && priority != DEF_PRIORITY)
continue; /* Let kswapd poll it */
sc->all_unreclaimable = 0;
@@ -1368,7 +1368,8 @@
if (!populated_zone(zone))
continue;
- if (zone->all_unreclaimable && priority != DEF_PRIORITY)
+ if (zone_is_all_unreclaimable(zone) &&
+ priority != DEF_PRIORITY)
continue;
if (!zone_watermark_ok(zone, order, zone->pages_high,
@@ -1403,7 +1404,8 @@
if (!populated_zone(zone))
continue;
- if (zone->all_unreclaimable && priority != DEF_PRIORITY)
+ if (zone_is_all_unreclaimable(zone) &&
+ priority != DEF_PRIORITY)
continue;
if (!zone_watermark_ok(zone, order, zone->pages_high,
@@ -1424,12 +1426,13 @@
lru_pages);
nr_reclaimed += reclaim_state->reclaimed_slab;
total_scanned += sc.nr_scanned;
- if (zone->all_unreclaimable)
+ if (zone_is_all_unreclaimable(zone))
continue;
if (nr_slab == 0 && zone->pages_scanned >=
(zone_page_state(zone, NR_ACTIVE)
+ zone_page_state(zone, NR_INACTIVE)) * 6)
- zone->all_unreclaimable = 1;
+ zone_set_flag(zone,
+ ZONE_ALL_UNRECLAIMABLE);
/*
* If we've done a decent amount of scanning and
* the reclaim ratio is low, start doing writepage
@@ -1595,7 +1598,7 @@
if (!populated_zone(zone))
continue;
- if (zone->all_unreclaimable && prio != DEF_PRIORITY)
+ if (zone_is_all_unreclaimable(zone) && prio != DEF_PRIORITY)
continue;
/* For pass = 0 we don't shrink the active list */
@@ -1919,10 +1922,8 @@
* not have reclaimable pages and if we should not delay the allocation
* then do not scan.
*/
- if (!(gfp_mask & __GFP_WAIT) ||
- zone->all_unreclaimable ||
- atomic_read(&zone->reclaim_in_progress) > 0 ||
- (current->flags & PF_MEMALLOC))
+ if (!(gfp_mask & __GFP_WAIT) || zone_is_all_unreclaimable(zone) ||
+ zone_is_reclaim_locked(zone) || (current->flags & PF_MEMALLOC))
return 0;
/*
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 3b5e904..4651bf1 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -704,7 +704,7 @@
"\n all_unreclaimable: %u"
"\n prev_priority: %i"
"\n start_pfn: %lu",
- zone->all_unreclaimable,
+ zone_is_all_unreclaimable(zone),
zone->prev_priority,
zone->zone_start_pfn);
seq_putc(m, '\n');