Commit e815af95 authored by David Rientjes's avatar David Rientjes Committed by Linus Torvalds
Browse files

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: default avatarChristoph Lameter <clameter@sgi.com>
Signed-off-by: default avatarDavid Rientjes <rientjes@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 70e24bdf

include/linux/mmzone.h

+25 −4
Original line number Diff line number Diff line
@@ -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 @@ struct zone { 
	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 @@ struct zone { 
	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

mm/page_alloc.c

+4 −4
Original line number Diff line number Diff line
@@ -490,7 +490,7 @@ static void free_pages_bulk(struct zone *zone, int count, 
					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_pages_bulk(struct zone *zone, int count, 
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 @@ void show_free_areas(void) 
			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 @@ static void __meminit free_area_init_core(struct pglist_data *pgdat, 
		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;

mm/vmscan.c

+13 −12
Original line number Diff line number Diff line
@@ -1108,7 +1108,7 @@ static unsigned long shrink_zone(int priority, struct zone *zone, 
	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 @@ static unsigned long shrink_zone(int priority, struct zone *zone, 


	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 @@ static unsigned long shrink_zones(int priority, struct zone **zones, 


		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 @@ loop_again: 
			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 @@ loop_again: 
			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 @@ loop_again: 
						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 @@ static unsigned long shrink_all_zones(unsigned long nr_pages, int prio, 
		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 @@ int zone_reclaim(struct zone *zone, gfp_t gfp_mask, unsigned int order) 
	 * 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;



	/*

mm/vmstat.c

+1 −1
Original line number Diff line number Diff line
@@ -704,7 +704,7 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat, 
		   "\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');

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