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mm: page_isolation: check specified range for unmovable pages

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Enable set_migratetype_isolate() to check specified range for unmovable
pages during isolation to prepare arbitrary range page isolation.  The
functionality will take effect in upcoming commits by adjusting the
callers of start_isolate_page_range(), which uses
set_migratetype_isolate().

For example, alloc_contig_range(), which calls start_isolate_page_range(),
accepts unaligned ranges, but because page isolation is currently done at
MAX_ORDER_NR_PAEGS granularity, pages that are out of the specified range
but withint MAX_ORDER_NR_PAEGS alignment might be attempted for isolation
and the failure of isolating these unrelated pages fails the whole
operation undesirably.

Link: https://lkml.kernel.org/r/20220425143118.2850746-3-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David Hildenbrand <david@redhat.com>
Cc: Eric Ren <renzhengeek@gmail.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Zi Yan 2022-05-12 20:22:58 -07:00 committed by Andrew Morton
parent b48d8a8e5c
commit 844fbae63e
1 changed files with 34 additions and 13 deletions
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45
mm/page_isolation.c
View File

@ -16,7 +16,9 @@
#include <trace/events/page_isolation.h>
/*
* This function checks whether pageblock includes unmovable pages or not.
* This function checks whether the range [start_pfn, end_pfn) includes
* unmovable pages or not. The range must fall into a single pageblock and
* consequently belong to a single zone.
*
* PageLRU check without isolation or lru_lock could race so that
* MIGRATE_MOVABLE block might include unmovable pages. And __PageMovable
@ -28,12 +30,15 @@
* cannot get removed (e.g., via memory unplug) concurrently.
*
*/
static struct page *has_unmovable_pages(struct zone *zone, struct page *page,
static struct page *has_unmovable_pages(unsigned long start_pfn, unsigned long end_pfn,
int migratetype, int flags)
{
unsigned long iter = 0;
unsigned long pfn = page_to_pfn(page);
unsigned long offset = pfn % pageblock_nr_pages;
struct page *page = pfn_to_page(start_pfn);
struct zone *zone = page_zone(page);
unsigned long pfn;
VM_BUG_ON(ALIGN_DOWN(start_pfn, pageblock_nr_pages) !=
ALIGN_DOWN(end_pfn - 1, pageblock_nr_pages));
if (is_migrate_cma_page(page)) {
/*
@ -47,8 +52,8 @@ static struct page *has_unmovable_pages(struct zone *zone, struct page *page,
return page;
}
for (; iter < pageblock_nr_pages - offset; iter++) {
page = pfn_to_page(pfn + iter);
for (pfn = start_pfn; pfn < end_pfn; pfn++) {
page = pfn_to_page(pfn);
/*
* Both, bootmem allocations and memory holes are marked
@ -85,7 +90,7 @@ static struct page *has_unmovable_pages(struct zone *zone, struct page *page,
}
skip_pages = compound_nr(head) - (page - head);
iter += skip_pages - 1;
pfn += skip_pages - 1;
continue;
}
@ -97,7 +102,7 @@ static struct page *has_unmovable_pages(struct zone *zone, struct page *page,
*/
if (!page_ref_count(page)) {
if (PageBuddy(page))
iter += (1 << buddy_order(page)) - 1;
pfn += (1 << buddy_order(page)) - 1;
continue;
}
@ -134,11 +139,18 @@ static struct page *has_unmovable_pages(struct zone *zone, struct page *page,
return NULL;
}
static int set_migratetype_isolate(struct page *page, int migratetype, int isol_flags)
/*
* This function set pageblock migratetype to isolate if no unmovable page is
* present in [start_pfn, end_pfn). The pageblock must intersect with
* [start_pfn, end_pfn).
*/
static int set_migratetype_isolate(struct page *page, int migratetype, int isol_flags,
unsigned long start_pfn, unsigned long end_pfn)
{
struct zone *zone = page_zone(page);
struct page *unmovable;
unsigned long flags;
unsigned long check_unmovable_start, check_unmovable_end;
spin_lock_irqsave(&zone->lock, flags);
@ -155,8 +167,16 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_
/*
* FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
* We just check MOVABLE pages.
*
* Pass the intersection of [start_pfn, end_pfn) and the page's pageblock
* to avoid redundant checks.
*/
unmovable = has_unmovable_pages(zone, page, migratetype, isol_flags);
check_unmovable_start = max(page_to_pfn(page), start_pfn);
check_unmovable_end = min(ALIGN(page_to_pfn(page) + 1, pageblock_nr_pages),
end_pfn);
unmovable = has_unmovable_pages(check_unmovable_start, check_unmovable_end,
migratetype, isol_flags);
if (!unmovable) {
unsigned long nr_pages;
int mt = get_pageblock_migratetype(page);
@ -313,7 +333,8 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
pfn < end_pfn;
pfn += pageblock_nr_pages) {
page = __first_valid_page(pfn, pageblock_nr_pages);
if (page && set_migratetype_isolate(page, migratetype, flags)) {
if (page && set_migratetype_isolate(page, migratetype, flags,
start_pfn, end_pfn)) {
undo_isolate_page_range(start_pfn, pfn, migratetype);
return -EBUSY;
}