switch-linux/include/linux/compaction.h
Michal Hocko c8f7de0bfa mm, compaction: distinguish between full and partial COMPACT_COMPLETE
COMPACT_COMPLETE now means that compaction and free scanner met.  This
is not very useful information if somebody just wants to use this
feedback and make any decisions based on that.  The current caller might
be a poor guy who just happened to scan tiny portion of the zone and
that could be the reason no suitable pages were compacted.  Make sure we
distinguish the full and partial zone walks.

Consumers should treat COMPACT_PARTIAL_SKIPPED as a potential success
and be optimistic in retrying.

The existing users of COMPACT_COMPLETE are conservatively changed to use
COMPACT_PARTIAL_SKIPPED as well but some of them should be probably
reconsidered and only defer the compaction only for COMPACT_COMPLETE
with the new semantic.

This patch shouldn't introduce any functional changes.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Joonsoo Kim <js1304@gmail.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-05-20 17:58:30 -07:00

141 lines
4 KiB
C

#ifndef _LINUX_COMPACTION_H
#define _LINUX_COMPACTION_H
/* Return values for compact_zone() and try_to_compact_pages() */
/* When adding new states, please adjust include/trace/events/compaction.h */
enum compact_result {
/*
* compaction didn't start as it was not possible or direct reclaim
* was more suitable
*/
COMPACT_SKIPPED,
/* compaction didn't start as it was deferred due to past failures */
COMPACT_DEFERRED,
/* compaction not active last round */
COMPACT_INACTIVE = COMPACT_DEFERRED,
/* compaction should continue to another pageblock */
COMPACT_CONTINUE,
/*
* direct compaction partially compacted a zone and there are suitable
* pages
*/
COMPACT_PARTIAL,
/*
* direct compaction has scanned part of the zone but wasn't successfull
* to compact suitable pages.
*/
COMPACT_PARTIAL_SKIPPED,
/*
* The full zone was compacted scanned but wasn't successfull to compact
* suitable pages.
*/
COMPACT_COMPLETE,
/* For more detailed tracepoint output */
COMPACT_NO_SUITABLE_PAGE,
COMPACT_NOT_SUITABLE_ZONE,
COMPACT_CONTENDED,
};
/* Used to signal whether compaction detected need_sched() or lock contention */
/* No contention detected */
#define COMPACT_CONTENDED_NONE 0
/* Either need_sched() was true or fatal signal pending */
#define COMPACT_CONTENDED_SCHED 1
/* Zone lock or lru_lock was contended in async compaction */
#define COMPACT_CONTENDED_LOCK 2
struct alloc_context; /* in mm/internal.h */
#ifdef CONFIG_COMPACTION
extern int sysctl_compact_memory;
extern int sysctl_compaction_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos);
extern int sysctl_extfrag_threshold;
extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *length, loff_t *ppos);
extern int sysctl_compact_unevictable_allowed;
extern int fragmentation_index(struct zone *zone, unsigned int order);
extern enum compact_result try_to_compact_pages(gfp_t gfp_mask,
unsigned int order,
unsigned int alloc_flags, const struct alloc_context *ac,
enum migrate_mode mode, int *contended);
extern void compact_pgdat(pg_data_t *pgdat, int order);
extern void reset_isolation_suitable(pg_data_t *pgdat);
extern enum compact_result compaction_suitable(struct zone *zone, int order,
unsigned int alloc_flags, int classzone_idx);
extern void defer_compaction(struct zone *zone, int order);
extern bool compaction_deferred(struct zone *zone, int order);
extern void compaction_defer_reset(struct zone *zone, int order,
bool alloc_success);
extern bool compaction_restarting(struct zone *zone, int order);
extern int kcompactd_run(int nid);
extern void kcompactd_stop(int nid);
extern void wakeup_kcompactd(pg_data_t *pgdat, int order, int classzone_idx);
#else
static inline enum compact_result try_to_compact_pages(gfp_t gfp_mask,
unsigned int order, int alloc_flags,
const struct alloc_context *ac,
enum migrate_mode mode, int *contended)
{
return COMPACT_CONTINUE;
}
static inline void compact_pgdat(pg_data_t *pgdat, int order)
{
}
static inline void reset_isolation_suitable(pg_data_t *pgdat)
{
}
static inline enum compact_result compaction_suitable(struct zone *zone, int order,
int alloc_flags, int classzone_idx)
{
return COMPACT_SKIPPED;
}
static inline void defer_compaction(struct zone *zone, int order)
{
}
static inline bool compaction_deferred(struct zone *zone, int order)
{
return true;
}
static inline int kcompactd_run(int nid)
{
return 0;
}
static inline void kcompactd_stop(int nid)
{
}
static inline void wakeup_kcompactd(pg_data_t *pgdat, int order, int classzone_idx)
{
}
#endif /* CONFIG_COMPACTION */
#if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
extern int compaction_register_node(struct node *node);
extern void compaction_unregister_node(struct node *node);
#else
static inline int compaction_register_node(struct node *node)
{
return 0;
}
static inline void compaction_unregister_node(struct node *node)
{
}
#endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
#endif /* _LINUX_COMPACTION_H */