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memory unplug: page isolation

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Implement generic chunk-of-pages isolation method by using page grouping ops.

This patch add MIGRATE_ISOLATE to MIGRATE_TYPES. By this
 - MIGRATE_TYPES increases.
 - bitmap for migratetype is enlarged.

pages of MIGRATE_ISOLATE migratetype will not be allocated even if it is free.
By this, you can isolated *freed* pages from users. How-to-free pages is not
a purpose of this patch. You may use reclaim and migrate codes to free pages.

If start_isolate_page_range(start,end) is called,
 - migratetype of the range turns to be MIGRATE_ISOLATE  if
   its type is MIGRATE_MOVABLE. (*) this check can be updated if other
   memory reclaiming works make progress.
 - MIGRATE_ISOLATE is not on migratetype fallback list.
 - All free pages and will-be-freed pages are isolated.
To check all pages in the range are isolated or not,  use test_pages_isolated(),
To cancel isolation, use undo_isolate_page_range().

Changes V6 -> V7
 - removed unnecessary #ifdef

There are HOLES_IN_ZONE handling codes...I'm glad if we can remove them..

Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
KAMEZAWA Hiroyuki
2007-10-16 01:26:11 -07:00
committed by Linus Torvalds
parent 75884fb1c6
commit a5d76b54a3
6 changed files with 223 additions and 3 deletions
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44
mm/page_alloc.c
View File

@@ -41,6 +41,7 @@
#include <linux/pfn.h>
#include <linux/backing-dev.h>
#include <linux/fault-inject.h>
#include <linux/page-isolation.h>
#include <asm/tlbflush.h>
#include <asm/div64.h>
@@ -4433,3 +4434,46 @@ void set_pageblock_flags_group(struct page *page, unsigned long flags,
else
__clear_bit(bitidx + start_bitidx, bitmap);
}
/*
* This is designed as sub function...plz see page_isolation.c also.
* set/clear page block's type to be ISOLATE.
* page allocater never alloc memory from ISOLATE block.
*/
int set_migratetype_isolate(struct page *page)
{
struct zone *zone;
unsigned long flags;
int ret = -EBUSY;
zone = page_zone(page);
spin_lock_irqsave(&zone->lock, flags);
/*
* In future, more migrate types will be able to be isolation target.
*/
if (get_pageblock_migratetype(page) != MIGRATE_MOVABLE)
goto out;
set_pageblock_migratetype(page, MIGRATE_ISOLATE);
move_freepages_block(zone, page, MIGRATE_ISOLATE);
ret = 0;
out:
spin_unlock_irqrestore(&zone->lock, flags);
if (!ret)
drain_all_local_pages();
return ret;
}
void unset_migratetype_isolate(struct page *page)
{
struct zone *zone;
unsigned long flags;
zone = page_zone(page);
spin_lock_irqsave(&zone->lock, flags);
if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
goto out;
set_pageblock_migratetype(page, MIGRATE_MOVABLE);
move_freepages_block(zone, page, MIGRATE_MOVABLE);
out:
spin_unlock_irqrestore(&zone->lock, flags);
}