git://bbs.cooldavid.org / net-next-2.6.git / blame
| Commit | Line | Data |
|---|---|---|
| 95144c78 KH |
1 | /* |
| 2 | * linux/mm/mmzone.c | |
| 3 | * | |
| 4 | * management codes for pgdats and zones. | |
| 5 | */ | |
| 6 | ||
| 7 | ||
| 95144c78 | 8 | #include <linux/stddef.h> |
| eb33575c | 9 | #include <linux/mm.h> |
| 95144c78 KH |
10 | #include <linux/mmzone.h> |
| 11 | #include <linux/module.h> | |
| 12 | ||
| 13 | struct pglist_data *first_online_pgdat(void) | |
| 14 | { | |
| 15 | return NODE_DATA(first_online_node); | |
| 16 | } | |
| 17 | ||
| 95144c78 KH |
18 | struct pglist_data *next_online_pgdat(struct pglist_data *pgdat) |
| 19 | { | |
| 20 | int nid = next_online_node(pgdat->node_id); | |
| 21 | ||
| 22 | if (nid == MAX_NUMNODES) | |
| 23 | return NULL; | |
| 24 | return NODE_DATA(nid); | |
| 25 | } | |
| 95144c78 KH |
26 | |
| 27 | /* | |
| 28 | * next_zone - helper magic for for_each_zone() | |
| 29 | */ | |
| 30 | struct zone *next_zone(struct zone *zone) | |
| 31 | { | |
| 32 | pg_data_t *pgdat = zone->zone_pgdat; | |
| 33 | ||
| 34 | if (zone < pgdat->node_zones + MAX_NR_ZONES - 1) | |
| 35 | zone++; | |
| 36 | else { | |
| 37 | pgdat = next_online_pgdat(pgdat); | |
| 38 | if (pgdat) | |
| 39 | zone = pgdat->node_zones; | |
| 40 | else | |
| 41 | zone = NULL; | |
| 42 | } | |
| 43 | return zone; | |
| 44 | } | |
| 95144c78 | 45 | |
| 19770b32 MG |
46 | static inline int zref_in_nodemask(struct zoneref *zref, nodemask_t *nodes) |
| 47 | { | |
| 48 | #ifdef CONFIG_NUMA | |
| 49 | return node_isset(zonelist_node_idx(zref), *nodes); | |
| 50 | #else | |
| 51 | return 1; | |
| 52 | #endif /* CONFIG_NUMA */ | |
| 53 | } | |
| 54 | ||
| 55 | /* Returns the next zone at or below highest_zoneidx in a zonelist */ | |
| 56 | struct zoneref *next_zones_zonelist(struct zoneref *z, | |
| 57 | enum zone_type highest_zoneidx, | |
| 58 | nodemask_t *nodes, | |
| 59 | struct zone **zone) | |
| 60 | { | |
| 61 | /* | |
| 62 | * Find the next suitable zone to use for the allocation. | |
| 63 | * Only filter based on nodemask if it's set | |
| 64 | */ | |
| 65 | if (likely(nodes == NULL)) | |
| 66 | while (zonelist_zone_idx(z) > highest_zoneidx) | |
| 67 | z++; | |
| 68 | else | |
| 69 | while (zonelist_zone_idx(z) > highest_zoneidx || | |
| 70 | (z->zone && !zref_in_nodemask(z, nodes))) | |
| 71 | z++; | |
| 72 | ||
| 5bead2a0 | 73 | *zone = zonelist_zone(z); |
| 19770b32 MG |
74 | return z; |
| 75 | } | |
| eb33575c MG |
76 | |
| 77 | #ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL | |
| 78 | int memmap_valid_within(unsigned long pfn, | |
| 79 | struct page *page, struct zone *zone) | |
| 80 | { | |
| 81 | if (page_to_pfn(page) != pfn) | |
| 82 | return 0; | |
| 83 | ||
| 84 | if (page_zone(page) != zone) | |
| 85 | return 0; | |
| 86 | ||
| 87 | return 1; | |
| 88 | } | |
| 89 | #endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */ | |
| aa454840 CL |
90 | |
| 91 | #ifdef CONFIG_SMP | |
| 92 | /* Called when a more accurate view of NR_FREE_PAGES is needed */ | |
| 93 | unsigned long zone_nr_free_pages(struct zone *zone) | |
| 94 | { | |
| 95 | unsigned long nr_free_pages = zone_page_state(zone, NR_FREE_PAGES); | |
| 96 | ||
| 97 | /* | |
| 98 | * While kswapd is awake, it is considered the zone is under some | |
| 99 | * memory pressure. Under pressure, there is a risk that | |
| 100 | * per-cpu-counter-drift will allow the min watermark to be breached | |
| 101 | * potentially causing a live-lock. While kswapd is awake and | |
| 102 | * free pages are low, get a better estimate for free pages | |
| 103 | */ | |
| 104 | if (nr_free_pages < zone->percpu_drift_mark && | |
| 105 | !waitqueue_active(&zone->zone_pgdat->kswapd_wait)) | |
| 106 | return zone_page_state_snapshot(zone, NR_FREE_PAGES); | |
| 107 | ||
| 108 | return nr_free_pages; | |
| 109 | } | |
| 110 | #endif /* CONFIG_SMP */ |