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Commit 06b6640a authored by Vlastimil Babka's avatar Vlastimil Babka Committed by Linus Torvalds
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mm, compaction: wrap calculating first and last pfn of pageblock 



Compaction code has accumulated numerous instances of manual
calculations of the first (inclusive) and last (exclusive) pfn of a
pageblock (or a smaller block of given order), given a pfn within the
pageblock.

Wrap these calculations by introducing pageblock_start_pfn(pfn) and
pageblock_end_pfn(pfn) macros.

[vbabka@suse.cz: fix crash in get_pfnblock_flags_mask() from isolate_freepages():]
Signed-off-by: default avatarVlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e4c5800a

mm/compaction.c

+19 −14
Original line number Diff line number Diff line
@@ -42,6 +42,11 @@ static inline void count_compact_events(enum vm_event_item item, long delta) 
#define CREATE_TRACE_POINTS

#include <trace/events/compaction.h>



#define block_start_pfn(pfn, order)	round_down(pfn, 1UL << (order))

#define block_end_pfn(pfn, order)	ALIGN((pfn) + 1, 1UL << (order))

#define pageblock_start_pfn(pfn)	block_start_pfn(pfn, pageblock_order)

#define pageblock_end_pfn(pfn)		block_end_pfn(pfn, pageblock_order)



static unsigned long release_freepages(struct list_head *freelist)

{

	struct page *page, *next;
@@ -161,7 +166,7 @@ static void reset_cached_positions(struct zone *zone) 
	zone->compact_cached_migrate_pfn[0] = zone->zone_start_pfn;

	zone->compact_cached_migrate_pfn[1] = zone->zone_start_pfn;

	zone->compact_cached_free_pfn =

			round_down(zone_end_pfn(zone) - 1, pageblock_nr_pages);

				pageblock_start_pfn(zone_end_pfn(zone) - 1);

}



/*
@@ -519,10 +524,10 @@ isolate_freepages_range(struct compact_control *cc, 
	LIST_HEAD(freelist);



	pfn = start_pfn;

	block_start_pfn = pfn & ~(pageblock_nr_pages - 1);

	block_start_pfn = pageblock_start_pfn(pfn);

	if (block_start_pfn < cc->zone->zone_start_pfn)

		block_start_pfn = cc->zone->zone_start_pfn;

	block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);

	block_end_pfn = pageblock_end_pfn(pfn);



	for (; pfn < end_pfn; pfn += isolated,

				block_start_pfn = block_end_pfn,
@@ -538,8 +543,8 @@ isolate_freepages_range(struct compact_control *cc, 
		 * scanning range to right one.

		 */

		if (pfn >= block_end_pfn) {

			block_start_pfn = pfn & ~(pageblock_nr_pages - 1);

			block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);

			block_start_pfn = pageblock_start_pfn(pfn);

			block_end_pfn = pageblock_end_pfn(pfn);

			block_end_pfn = min(block_end_pfn, end_pfn);

		}
@@ -834,10 +839,10 @@ isolate_migratepages_range(struct compact_control *cc, unsigned long start_pfn, 


	/* Scan block by block. First and last block may be incomplete */

	pfn = start_pfn;

	block_start_pfn = pfn & ~(pageblock_nr_pages - 1);

	block_start_pfn = pageblock_start_pfn(pfn);

	if (block_start_pfn < cc->zone->zone_start_pfn)

		block_start_pfn = cc->zone->zone_start_pfn;

	block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);

	block_end_pfn = pageblock_end_pfn(pfn);



	for (; pfn < end_pfn; pfn = block_end_pfn,

				block_start_pfn = block_end_pfn,
@@ -924,10 +929,10 @@ static void isolate_freepages(struct compact_control *cc) 
	 * is using.

	 */

	isolate_start_pfn = cc->free_pfn;

	block_start_pfn = cc->free_pfn & ~(pageblock_nr_pages-1);

	block_start_pfn = pageblock_start_pfn(cc->free_pfn);

	block_end_pfn = min(block_start_pfn + pageblock_nr_pages,

						zone_end_pfn(zone));

	low_pfn = ALIGN(cc->migrate_pfn + 1, pageblock_nr_pages);

	low_pfn = pageblock_end_pfn(cc->migrate_pfn);



	/*

	 * Isolate free pages until enough are available to migrate the
@@ -1081,12 +1086,12 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, 
	 * initialized by compact_zone()

	 */

	low_pfn = cc->migrate_pfn;

	block_start_pfn = cc->migrate_pfn & ~(pageblock_nr_pages - 1);

	block_start_pfn = pageblock_start_pfn(low_pfn);

	if (block_start_pfn < zone->zone_start_pfn)

		block_start_pfn = zone->zone_start_pfn;



	/* Only scan within a pageblock boundary */

	block_end_pfn = ALIGN(low_pfn + 1, pageblock_nr_pages);

	block_end_pfn = pageblock_end_pfn(low_pfn);



	/*

	 * Iterate over whole pageblocks until we find the first suitable.
@@ -1343,7 +1348,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) 
	cc->migrate_pfn = zone->compact_cached_migrate_pfn[sync];

	cc->free_pfn = zone->compact_cached_free_pfn;

	if (cc->free_pfn < start_pfn || cc->free_pfn >= end_pfn) {

		cc->free_pfn = round_down(end_pfn - 1, pageblock_nr_pages);

		cc->free_pfn = pageblock_start_pfn(end_pfn - 1);

		zone->compact_cached_free_pfn = cc->free_pfn;

	}

	if (cc->migrate_pfn < start_pfn || cc->migrate_pfn >= end_pfn) {
@@ -1411,7 +1416,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) 
		if (cc->order > 0 && cc->last_migrated_pfn) {

			int cpu;

			unsigned long current_block_start =

				cc->migrate_pfn & ~((1UL << cc->order) - 1);

				block_start_pfn(cc->migrate_pfn, cc->order);



			if (cc->last_migrated_pfn < current_block_start) {

				cpu = get_cpu();
@@ -1436,7 +1441,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc) 
		cc->nr_freepages = 0;

		VM_BUG_ON(free_pfn == 0);

		/* The cached pfn is always the first in a pageblock */

		free_pfn &= ~(pageblock_nr_pages-1);

		free_pfn = pageblock_start_pfn(free_pfn);

		/*

		 * Only go back, not forward. The cached pfn might have been

		 * already reset to zone end in compact_finished()