111 lines
2.5 KiB
C
111 lines
2.5 KiB
C
/*
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* linux/mm/mmzone.c
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*
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* management codes for pgdats and zones.
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*/
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#include <linux/stddef.h>
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#include <linux/mm.h>
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#include <linux/mmzone.h>
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#include <linux/module.h>
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struct pglist_data *first_online_pgdat(void)
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{
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return NODE_DATA(first_online_node);
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}
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struct pglist_data *next_online_pgdat(struct pglist_data *pgdat)
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{
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int nid = next_online_node(pgdat->node_id);
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if (nid == MAX_NUMNODES)
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return NULL;
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return NODE_DATA(nid);
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}
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/*
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* next_zone - helper magic for for_each_zone()
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*/
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struct zone *next_zone(struct zone *zone)
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{
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pg_data_t *pgdat = zone->zone_pgdat;
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if (zone < pgdat->node_zones + MAX_NR_ZONES - 1)
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zone++;
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else {
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pgdat = next_online_pgdat(pgdat);
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if (pgdat)
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zone = pgdat->node_zones;
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else
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zone = NULL;
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}
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return zone;
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}
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static inline int zref_in_nodemask(struct zoneref *zref, nodemask_t *nodes)
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{
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#ifdef CONFIG_NUMA
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return node_isset(zonelist_node_idx(zref), *nodes);
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#else
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return 1;
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#endif /* CONFIG_NUMA */
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}
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/* Returns the next zone at or below highest_zoneidx in a zonelist */
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struct zoneref *next_zones_zonelist(struct zoneref *z,
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enum zone_type highest_zoneidx,
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nodemask_t *nodes,
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struct zone **zone)
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{
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/*
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* Find the next suitable zone to use for the allocation.
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* Only filter based on nodemask if it's set
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*/
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if (likely(nodes == NULL))
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while (zonelist_zone_idx(z) > highest_zoneidx)
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z++;
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else
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while (zonelist_zone_idx(z) > highest_zoneidx ||
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(z->zone && !zref_in_nodemask(z, nodes)))
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z++;
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*zone = zonelist_zone(z);
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return z;
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}
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#ifdef CONFIG_ARCH_HAS_HOLES_MEMORYMODEL
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int memmap_valid_within(unsigned long pfn,
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struct page *page, struct zone *zone)
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{
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if (page_to_pfn(page) != pfn)
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return 0;
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if (page_zone(page) != zone)
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return 0;
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return 1;
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}
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#endif /* CONFIG_ARCH_HAS_HOLES_MEMORYMODEL */
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#ifdef CONFIG_SMP
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/* Called when a more accurate view of NR_FREE_PAGES is needed */
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unsigned long zone_nr_free_pages(struct zone *zone)
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{
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unsigned long nr_free_pages = zone_page_state(zone, NR_FREE_PAGES);
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/*
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* While kswapd is awake, it is considered the zone is under some
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* memory pressure. Under pressure, there is a risk that
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* per-cpu-counter-drift will allow the min watermark to be breached
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* potentially causing a live-lock. While kswapd is awake and
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* free pages are low, get a better estimate for free pages
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*/
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if (nr_free_pages < zone->percpu_drift_mark &&
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!waitqueue_active(&zone->zone_pgdat->kswapd_wait))
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return zone_page_state_snapshot(zone, NR_FREE_PAGES);
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return nr_free_pages;
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}
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#endif /* CONFIG_SMP */
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