memory unplug: page isolation
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>hifive-unleashed-5.1
KAMEZAWA Hiroyuki
Linus Torvalds
parent
75884fb1c6
commit
a5d76b54a3
|
|
@ -37,7 +37,8 @@
|
|||
#define MIGRATE_RECLAIMABLE 1
|
||||
#define MIGRATE_MOVABLE 2
|
||||
#define MIGRATE_RESERVE 3
|
||||
#define MIGRATE_TYPES 4
|
||||
#define MIGRATE_ISOLATE 4 /* can't allocate from here */
|
||||
#define MIGRATE_TYPES 5
|
||||
|
||||
#define for_each_migratetype_order(order, type) \
|
||||
for (order = 0; order < MAX_ORDER; order++) \
|
||||
|
|
|
|||
|
|
@ -0,0 +1,37 @@
|
|||
#ifndef __LINUX_PAGEISOLATION_H
|
||||
#define __LINUX_PAGEISOLATION_H
|
||||
|
||||
/*
|
||||
* Changes migrate type in [start_pfn, end_pfn) to be MIGRATE_ISOLATE.
|
||||
* If specified range includes migrate types other than MOVABLE,
|
||||
* this will fail with -EBUSY.
|
||||
*
|
||||
* For isolating all pages in the range finally, the caller have to
|
||||
* free all pages in the range. test_page_isolated() can be used for
|
||||
* test it.
|
||||
*/
|
||||
extern int
|
||||
start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn);
|
||||
|
||||
/*
|
||||
* Changes MIGRATE_ISOLATE to MIGRATE_MOVABLE.
|
||||
* target range is [start_pfn, end_pfn)
|
||||
*/
|
||||
extern int
|
||||
undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn);
|
||||
|
||||
/*
|
||||
* test all pages in [start_pfn, end_pfn)are isolated or not.
|
||||
*/
|
||||
extern int
|
||||
test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn);
|
||||
|
||||
/*
|
||||
* Internal funcs.Changes pageblock's migrate type.
|
||||
* Please use make_pagetype_isolated()/make_pagetype_movable().
|
||||
*/
|
||||
extern int set_migratetype_isolate(struct page *page);
|
||||
extern void unset_migratetype_isolate(struct page *page);
|
||||
|
||||
|
||||
#endif
|
||||
|
|
@ -31,7 +31,7 @@
|
|||
|
||||
/* Bit indices that affect a whole block of pages */
|
||||
enum pageblock_bits {
|
||||
PB_range(PB_migrate, 2), /* 2 bits required for migrate types */
|
||||
PB_range(PB_migrate, 3), /* 3 bits required for migrate types */
|
||||
NR_PAGEBLOCK_BITS
|
||||
};
|
||||
|
||||
|
|
|
|||
|
|
@ -11,7 +11,7 @@ obj-y := bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \
|
|||
page_alloc.o page-writeback.o pdflush.o \
|
||||
readahead.o swap.o truncate.o vmscan.o \
|
||||
prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \
|
||||
$(mmu-y)
|
||||
page_isolation.o $(mmu-y)
|
||||
|
||||
obj-$(CONFIG_BOUNCE) += bounce.o
|
||||
obj-$(CONFIG_SWAP) += page_io.o swap_state.o swapfile.o thrash.o
|
||||
|
|
|
|||
|
|
@ -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);
|
||||
}
|
||||
|
|
|
|||
|
|
@ -0,0 +1,138 @@
|
|||
/*
|
||||
* linux/mm/page_isolation.c
|
||||
*/
|
||||
|
||||
#include <stddef.h>
|
||||
#include <linux/mm.h>
|
||||
#include <linux/page-isolation.h>
|
||||
#include <linux/pageblock-flags.h>
|
||||
#include "internal.h"
|
||||
|
||||
static inline struct page *
|
||||
__first_valid_page(unsigned long pfn, unsigned long nr_pages)
|
||||
{
|
||||
int i;
|
||||
for (i = 0; i < nr_pages; i++)
|
||||
if (pfn_valid_within(pfn + i))
|
||||
break;
|
||||
if (unlikely(i == nr_pages))
|
||||
return NULL;
|
||||
return pfn_to_page(pfn + i);
|
||||
}
|
||||
|
||||
/*
|
||||
* start_isolate_page_range() -- make page-allocation-type of range of pages
|
||||
* to be MIGRATE_ISOLATE.
|
||||
* @start_pfn: The lower PFN of the range to be isolated.
|
||||
* @end_pfn: The upper PFN of the range to be isolated.
|
||||
*
|
||||
* Making page-allocation-type to be MIGRATE_ISOLATE means free pages in
|
||||
* the range will never be allocated. Any free pages and pages freed in the
|
||||
* future will not be allocated again.
|
||||
*
|
||||
* start_pfn/end_pfn must be aligned to pageblock_order.
|
||||
* Returns 0 on success and -EBUSY if any part of range cannot be isolated.
|
||||
*/
|
||||
int
|
||||
start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn)
|
||||
{
|
||||
unsigned long pfn;
|
||||
unsigned long undo_pfn;
|
||||
struct page *page;
|
||||
|
||||
BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
|
||||
BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
|
||||
|
||||
for (pfn = start_pfn;
|
||||
pfn < end_pfn;
|
||||
pfn += pageblock_nr_pages) {
|
||||
page = __first_valid_page(pfn, pageblock_nr_pages);
|
||||
if (page && set_migratetype_isolate(page)) {
|
||||
undo_pfn = pfn;
|
||||
goto undo;
|
||||
}
|
||||
}
|
||||
return 0;
|
||||
undo:
|
||||
for (pfn = start_pfn;
|
||||
pfn <= undo_pfn;
|
||||
pfn += pageblock_nr_pages)
|
||||
unset_migratetype_isolate(pfn_to_page(pfn));
|
||||
|
||||
return -EBUSY;
|
||||
}
|
||||
|
||||
/*
|
||||
* Make isolated pages available again.
|
||||
*/
|
||||
int
|
||||
undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn)
|
||||
{
|
||||
unsigned long pfn;
|
||||
struct page *page;
|
||||
BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
|
||||
BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
|
||||
for (pfn = start_pfn;
|
||||
pfn < end_pfn;
|
||||
pfn += pageblock_nr_pages) {
|
||||
page = __first_valid_page(pfn, pageblock_nr_pages);
|
||||
if (!page || get_pageblock_flags(page) != MIGRATE_ISOLATE)
|
||||
continue;
|
||||
unset_migratetype_isolate(page);
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
/*
|
||||
* Test all pages in the range is free(means isolated) or not.
|
||||
* all pages in [start_pfn...end_pfn) must be in the same zone.
|
||||
* zone->lock must be held before call this.
|
||||
*
|
||||
* Returns 0 if all pages in the range is isolated.
|
||||
*/
|
||||
static int
|
||||
__test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn)
|
||||
{
|
||||
struct page *page;
|
||||
|
||||
while (pfn < end_pfn) {
|
||||
if (!pfn_valid_within(pfn)) {
|
||||
pfn++;
|
||||
continue;
|
||||
}
|
||||
page = pfn_to_page(pfn);
|
||||
if (PageBuddy(page))
|
||||
pfn += 1 << page_order(page);
|
||||
else if (page_count(page) == 0 &&
|
||||
page_private(page) == MIGRATE_ISOLATE)
|
||||
pfn += 1;
|
||||
else
|
||||
break;
|
||||
}
|
||||
if (pfn < end_pfn)
|
||||
return 0;
|
||||
return 1;
|
||||
}
|
||||
|
||||
int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
|
||||
{
|
||||
unsigned long pfn;
|
||||
struct page *page;
|
||||
|
||||
pfn = start_pfn;
|
||||
/*
|
||||
* Note: pageblock_nr_page != MAX_ORDER. Then, chunks of free page
|
||||
* is not aligned to pageblock_nr_pages.
|
||||
* Then we just check pagetype fist.
|
||||
*/
|
||||
for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
|
||||
page = __first_valid_page(pfn, pageblock_nr_pages);
|
||||
if (page && get_pageblock_flags(page) != MIGRATE_ISOLATE)
|
||||
break;
|
||||
}
|
||||
if (pfn < end_pfn)
|
||||
return -EBUSY;
|
||||
/* Check all pages are free or Marked as ISOLATED */
|
||||
if (__test_page_isolated_in_pageblock(start_pfn, end_pfn))
|
||||
return 0;
|
||||
return -EBUSY;
|
||||
}
|
||||
Loading…
Reference in New Issue