Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1#ifndef _LINUX_COMPACTION_H
2#define _LINUX_COMPACTION_H
3
4/* Return values for compact_zone() and try_to_compact_pages() */
5/* compaction didn't start as it was deferred due to past failures */
6#define COMPACT_DEFERRED 0
7/* compaction didn't start as it was not possible or direct reclaim was more suitable */
8#define COMPACT_SKIPPED 1
9/* compaction should continue to another pageblock */
10#define COMPACT_CONTINUE 2
11/* direct compaction partially compacted a zone and there are suitable pages */
12#define COMPACT_PARTIAL 3
13/* The full zone was compacted */
14#define COMPACT_COMPLETE 4
15
16/* Used to signal whether compaction detected need_sched() or lock contention */
17/* No contention detected */
18#define COMPACT_CONTENDED_NONE 0
19/* Either need_sched() was true or fatal signal pending */
20#define COMPACT_CONTENDED_SCHED 1
21/* Zone lock or lru_lock was contended in async compaction */
22#define COMPACT_CONTENDED_LOCK 2
23
24#ifdef CONFIG_COMPACTION
25extern int sysctl_compact_memory;
26extern int sysctl_compaction_handler(struct ctl_table *table, int write,
27 void __user *buffer, size_t *length, loff_t *ppos);
28extern int sysctl_extfrag_threshold;
29extern int sysctl_extfrag_handler(struct ctl_table *table, int write,
30 void __user *buffer, size_t *length, loff_t *ppos);
31
32extern int fragmentation_index(struct zone *zone, unsigned int order);
33extern unsigned long try_to_compact_pages(struct zonelist *zonelist,
34 int order, gfp_t gfp_mask, nodemask_t *mask,
35 enum migrate_mode mode, int *contended,
36 int alloc_flags, int classzone_idx);
37extern void compact_pgdat(pg_data_t *pgdat, int order);
38extern void reset_isolation_suitable(pg_data_t *pgdat);
39extern unsigned long compaction_suitable(struct zone *zone, int order,
40 int alloc_flags, int classzone_idx);
41
42/* Do not skip compaction more than 64 times */
43#define COMPACT_MAX_DEFER_SHIFT 6
44
45/*
46 * Compaction is deferred when compaction fails to result in a page
47 * allocation success. 1 << compact_defer_limit compactions are skipped up
48 * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT
49 */
50static inline void defer_compaction(struct zone *zone, int order)
51{
52 zone->compact_considered = 0;
53 zone->compact_defer_shift++;
54
55 if (order < zone->compact_order_failed)
56 zone->compact_order_failed = order;
57
58 if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT)
59 zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT;
60}
61
62/* Returns true if compaction should be skipped this time */
63static inline bool compaction_deferred(struct zone *zone, int order)
64{
65 unsigned long defer_limit = 1UL << zone->compact_defer_shift;
66
67 if (order < zone->compact_order_failed)
68 return false;
69
70 /* Avoid possible overflow */
71 if (++zone->compact_considered > defer_limit)
72 zone->compact_considered = defer_limit;
73
74 return zone->compact_considered < defer_limit;
75}
76
77/*
78 * Update defer tracking counters after successful compaction of given order,
79 * which means an allocation either succeeded (alloc_success == true) or is
80 * expected to succeed.
81 */
82static inline void compaction_defer_reset(struct zone *zone, int order,
83 bool alloc_success)
84{
85 if (alloc_success) {
86 zone->compact_considered = 0;
87 zone->compact_defer_shift = 0;
88 }
89 if (order >= zone->compact_order_failed)
90 zone->compact_order_failed = order + 1;
91}
92
93/* Returns true if restarting compaction after many failures */
94static inline bool compaction_restarting(struct zone *zone, int order)
95{
96 if (order < zone->compact_order_failed)
97 return false;
98
99 return zone->compact_defer_shift == COMPACT_MAX_DEFER_SHIFT &&
100 zone->compact_considered >= 1UL << zone->compact_defer_shift;
101}
102
103#else
104static inline unsigned long try_to_compact_pages(struct zonelist *zonelist,
105 int order, gfp_t gfp_mask, nodemask_t *nodemask,
106 enum migrate_mode mode, int *contended,
107 int alloc_flags, int classzone_idx)
108{
109 return COMPACT_CONTINUE;
110}
111
112static inline void compact_pgdat(pg_data_t *pgdat, int order)
113{
114}
115
116static inline void reset_isolation_suitable(pg_data_t *pgdat)
117{
118}
119
120static inline unsigned long compaction_suitable(struct zone *zone, int order,
121 int alloc_flags, int classzone_idx)
122{
123 return COMPACT_SKIPPED;
124}
125
126static inline void defer_compaction(struct zone *zone, int order)
127{
128}
129
130static inline bool compaction_deferred(struct zone *zone, int order)
131{
132 return true;
133}
134
135#endif /* CONFIG_COMPACTION */
136
137#if defined(CONFIG_COMPACTION) && defined(CONFIG_SYSFS) && defined(CONFIG_NUMA)
138extern int compaction_register_node(struct node *node);
139extern void compaction_unregister_node(struct node *node);
140
141#else
142
143static inline int compaction_register_node(struct node *node)
144{
145 return 0;
146}
147
148static inline void compaction_unregister_node(struct node *node)
149{
150}
151#endif /* CONFIG_COMPACTION && CONFIG_SYSFS && CONFIG_NUMA */
152
153#endif /* _LINUX_COMPACTION_H */