compaction.c (748446bb6b5a9390b546af38ec899c868a9dbcf0) compaction.c (76ab0f530e4a01d4dc20cdc1d5e87753c579dc18)
1/*
2 * linux/mm/compaction.c
3 *
4 * Memory compaction for the reduction of external fragmentation. Note that
5 * this heavily depends upon page migration to do all the real heavy
6 * lifting
7 *
8 * Copyright IBM Corp. 2007-2010 Mel Gorman <mel@csn.ul.ie>
9 */
10#include <linux/swap.h>
11#include <linux/migrate.h>
12#include <linux/compaction.h>
13#include <linux/mm_inline.h>
14#include <linux/backing-dev.h>
1/*
2 * linux/mm/compaction.c
3 *
4 * Memory compaction for the reduction of external fragmentation. Note that
5 * this heavily depends upon page migration to do all the real heavy
6 * lifting
7 *
8 * Copyright IBM Corp. 2007-2010 Mel Gorman <mel@csn.ul.ie>
9 */
10#include <linux/swap.h>
11#include <linux/migrate.h>
12#include <linux/compaction.h>
13#include <linux/mm_inline.h>
14#include <linux/backing-dev.h>
15#include <linux/sysctl.h>
15#include "internal.h"
16
17/*
18 * compact_control is used to track pages being migrated and the free pages
19 * they are being migrated to during memory compaction. The free_pfn starts
20 * at the end of a zone and migrate_pfn begins at the start. Movable pages
21 * are moved to the end of a zone during a compaction run and the run
22 * completes when free_pfn <= migrate_pfn

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386 }
387
388 /* Release free pages and check accounting */
389 cc->nr_freepages -= release_freepages(&cc->freepages);
390 VM_BUG_ON(cc->nr_freepages != 0);
391
392 return ret;
393}
16#include "internal.h"
17
18/*
19 * compact_control is used to track pages being migrated and the free pages
20 * they are being migrated to during memory compaction. The free_pfn starts
21 * at the end of a zone and migrate_pfn begins at the start. Movable pages
22 * are moved to the end of a zone during a compaction run and the run
23 * completes when free_pfn <= migrate_pfn

--- 363 unchanged lines hidden (view full) ---

387 }
388
389 /* Release free pages and check accounting */
390 cc->nr_freepages -= release_freepages(&cc->freepages);
391 VM_BUG_ON(cc->nr_freepages != 0);
392
393 return ret;
394}
395
396/* Compact all zones within a node */
397static int compact_node(int nid)
398{
399 int zoneid;
400 pg_data_t *pgdat;
401 struct zone *zone;
402
403 if (nid < 0 || nid >= nr_node_ids || !node_online(nid))
404 return -EINVAL;
405 pgdat = NODE_DATA(nid);
406
407 /* Flush pending updates to the LRU lists */
408 lru_add_drain_all();
409
410 for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) {
411 struct compact_control cc = {
412 .nr_freepages = 0,
413 .nr_migratepages = 0,
414 };
415
416 zone = &pgdat->node_zones[zoneid];
417 if (!populated_zone(zone))
418 continue;
419
420 cc.zone = zone;
421 INIT_LIST_HEAD(&cc.freepages);
422 INIT_LIST_HEAD(&cc.migratepages);
423
424 compact_zone(zone, &cc);
425
426 VM_BUG_ON(!list_empty(&cc.freepages));
427 VM_BUG_ON(!list_empty(&cc.migratepages));
428 }
429
430 return 0;
431}
432
433/* Compact all nodes in the system */
434static int compact_nodes(void)
435{
436 int nid;
437
438 for_each_online_node(nid)
439 compact_node(nid);
440
441 return COMPACT_COMPLETE;
442}
443
444/* The written value is actually unused, all memory is compacted */
445int sysctl_compact_memory;
446
447/* This is the entry point for compacting all nodes via /proc/sys/vm */
448int sysctl_compaction_handler(struct ctl_table *table, int write,
449 void __user *buffer, size_t *length, loff_t *ppos)
450{
451 if (write)
452 return compact_nodes();
453
454 return 0;
455}