linux/mm/page_isolation.c
Gerald Schaefer 6c1b7f680d memory hotplug: missing zone->lock in test_pages_isolated()
__test_page_isolated_in_pageblock() in mm/page_isolation.c has a comment
saying that the caller must hold zone->lock. But the only caller of that
function, test_pages_isolated(), does not hold zone->lock and the lock is
also not acquired anywhere before. This patch adds the missing zone->lock
to test_pages_isolated().

We reproducibly run into BUG_ON(!PageBuddy(page)) in __offline_isolated_pages()
during memory hotplug stress test, see trace below. This patch fixes that
problem, it would be good if we could have it in 2.6.27.

kernel BUG at /home/autobuild/BUILD/linux-2.6.26-20080909/mm/page_alloc.c:4561!
illegal operation: 0001 [#1] PREEMPT SMP
Modules linked in: dm_multipath sunrpc bonding qeth_l3 dm_mod qeth ccwgroup vmur
CPU: 1 Not tainted 2.6.26-29.x.20080909-s390default #1
Process memory_loop_all (pid: 10025, task: 2f444028, ksp: 2b10dd28)
Krnl PSW : 040c0000 801727ea (__offline_isolated_pages+0x18e/0x1c4)
 R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:0 CC:0 PM:0
Krnl GPRS: 00000000 7e27fc00 00000000 7e27fc00
 00000000 00000400 00014000 7e27fc01
 00606f00 7e27fc00 00013fe0 2b10dd28
 00000005 80172662 801727b2 2b10dd28
Krnl Code: 801727de: 5810900c l %r1,12(%r9)
 801727e2: a7f4ffb3 brc 15,80172748
 801727e6: a7f40001 brc 15,801727e8
 >801727ea: a7f4ffbc brc 15,80172762
 801727ee: a7f40001 brc 15,801727f0
 801727f2: a7f4ffaf brc 15,80172750
 801727f6: 0707 bcr 0,%r7
 801727f8: 0017 unknown
Call Trace:
([<0000000000172772>] __offline_isolated_pages+0x116/0x1c4)
 [<00000000001953a2>] offline_isolated_pages_cb+0x22/0x34
 [<000000000013164c>] walk_memory_resource+0xcc/0x11c
 [<000000000019520e>] offline_pages+0x36a/0x498
 [<00000000001004d6>] remove_memory+0x36/0x44
 [<000000000028fb06>] memory_block_change_state+0x112/0x150
 [<000000000028ffb8>] store_mem_state+0x90/0xe4
 [<0000000000289c00>] sysdev_store+0x34/0x40
 [<00000000001ee048>] sysfs_write_file+0xd0/0x178
 [<000000000019b1a8>] vfs_write+0x74/0x118
 [<000000000019b9ae>] sys_write+0x46/0x7c
 [<000000000011160e>] sysc_do_restart+0x12/0x16
 [<0000000077f3e8ca>] 0x77f3e8ca

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Acked-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>
2008-10-02 15:53:13 -07:00

142 lines
3.5 KiB
C

/*
* linux/mm/page_isolation.c
*/
#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_migratetype(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, flags;
struct page *page;
struct zone *zone;
int ret;
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_migratetype(page) != MIGRATE_ISOLATE)
break;
}
if (pfn < end_pfn)
return -EBUSY;
/* Check all pages are free or Marked as ISOLATED */
zone = page_zone(pfn_to_page(pfn));
spin_lock_irqsave(&zone->lock, flags);
ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn);
spin_unlock_irqrestore(&zone->lock, flags);
return ret ? 0 : -EBUSY;
}