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mm: make alloc_contig_range work at pageblock granularity

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alloc_contig_range() worked at MAX_ORDER_NR_PAGES granularity to avoid
merging pageblocks with different migratetypes.  It might unnecessarily
convert extra pageblocks at the beginning and at the end of the range. 
Change alloc_contig_range() to work at pageblock granularity.

Special handling is needed for free pages and in-use pages across the
boundaries of the range specified by alloc_contig_range().  Because these=

Partially isolated pages causes free page accounting issues.  The free
pages will be split and freed into separate migratetype lists; the in-use=

Pages will be migrated then the freed pages will be handled in the
aforementioned way.

[ziy@nvidia.com: fix deadlock/crash]
  Link: https://lkml.kernel.org/r/23A7297E-6C84-4138-A9FE-3598234004E6@nvidia.com
Link: https://lkml.kernel.org/r/20220425143118.2850746-4-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: David Hildenbrand <david@redhat.com>
Cc: Eric Ren <renzhengeek@gmail.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 844fbae63e
commit b2c9e2fbba
5 changed files with 242 additions and 18 deletions
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4
include/linux/page-isolation.h
View File

@ -42,7 +42,7 @@ int move_freepages_block(struct zone *zone, struct page *page,
*/
int
start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
unsigned migratetype, int flags);
int migratetype, int flags, gfp_t gfp_flags);
/*
* Changes MIGRATE_ISOLATE to MIGRATE_MOVABLE.
@ -50,7 +50,7 @@ start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
*/
void
undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
unsigned migratetype);
int migratetype);
/*
* Test all pages in [start_pfn, end_pfn) are isolated or not.

6
mm/internal.h
View File

@ -359,6 +359,9 @@ extern void *memmap_alloc(phys_addr_t size, phys_addr_t align,
phys_addr_t min_addr,
int nid, bool exact_nid);
void split_free_page(struct page *free_page,
int order, unsigned long split_pfn_offset);
#if defined CONFIG_COMPACTION || defined CONFIG_CMA
/*
@ -422,6 +425,9 @@ isolate_freepages_range(struct compact_control *cc,
int
isolate_migratepages_range(struct compact_control *cc,
unsigned long low_pfn, unsigned long end_pfn);
int __alloc_contig_migrate_range(struct compact_control *cc,
unsigned long start, unsigned long end);
#endif
int find_suitable_fallback(struct free_area *area, unsigned int order,
int migratetype, bool only_stealable, bool *can_steal);

3
mm/memory_hotplug.c
View File

@ -1837,7 +1837,8 @@ int __ref offline_pages(unsigned long start_pfn, unsigned long nr_pages,
/* set above range as isolated */
ret = start_isolate_page_range(start_pfn, end_pfn,
MIGRATE_MOVABLE,
MEMORY_OFFLINE | REPORT_FAILURE);
MEMORY_OFFLINE | REPORT_FAILURE,
GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL);
if (ret) {
reason = "failure to isolate range";
goto failed_removal_pcplists_disabled;

54
mm/page_alloc.c
View File

@ -1094,6 +1094,43 @@ done_merging:
page_reporting_notify_free(order);
}
/**
* split_free_page() -- split a free page at split_pfn_offset
* @free_page: the original free page
* @order: the order of the page
* @split_pfn_offset: split offset within the page
*
* It is used when the free page crosses two pageblocks with different migratetypes
* at split_pfn_offset within the page. The split free page will be put into
* separate migratetype lists afterwards. Otherwise, the function achieves
* nothing.
*/
void split_free_page(struct page *free_page,
int order, unsigned long split_pfn_offset)
{
struct zone *zone = page_zone(free_page);
unsigned long free_page_pfn = page_to_pfn(free_page);
unsigned long pfn;
unsigned long flags;
int free_page_order;
spin_lock_irqsave(&zone->lock, flags);
del_page_from_free_list(free_page, zone, order);
for (pfn = free_page_pfn;
pfn < free_page_pfn + (1UL << order);) {
int mt = get_pfnblock_migratetype(pfn_to_page(pfn), pfn);
free_page_order = ffs(split_pfn_offset) - 1;
__free_one_page(pfn_to_page(pfn), pfn, zone, free_page_order,
mt, FPI_NONE);
pfn += 1UL << free_page_order;
split_pfn_offset -= (1UL << free_page_order);
/* we have done the first part, now switch to second part */
if (split_pfn_offset == 0)
split_pfn_offset = (1UL << order) - (pfn - free_page_pfn);
}
spin_unlock_irqrestore(&zone->lock, flags);
}
/*
* A bad page could be due to a number of fields. Instead of multiple branches,
* try and check multiple fields with one check. The caller must do a detailed
@ -8951,7 +8988,7 @@ static inline void alloc_contig_dump_pages(struct list_head *page_list)
#endif
/* [start, end) must belong to a single zone. */
static int __alloc_contig_migrate_range(struct compact_control *cc,
int __alloc_contig_migrate_range(struct compact_control *cc,
unsigned long start, unsigned long end)
{
/* This function is based on compact_zone() from compaction.c. */
@ -9034,7 +9071,7 @@ int alloc_contig_range(unsigned long start, unsigned long end,
unsigned migratetype, gfp_t gfp_mask)
{
unsigned long outer_start, outer_end;
unsigned int order;
int order;
int ret = 0;
struct compact_control cc = {
@ -9053,14 +9090,11 @@ int alloc_contig_range(unsigned long start, unsigned long end,
* What we do here is we mark all pageblocks in range as
* MIGRATE_ISOLATE. Because pageblock and max order pages may
* have different sizes, and due to the way page allocator
* work, we align the range to biggest of the two pages so
* that page allocator won't try to merge buddies from
* different pageblocks and change MIGRATE_ISOLATE to some
* other migration type.
* work, start_isolate_page_range() has special handlings for this.
*
* Once the pageblocks are marked as MIGRATE_ISOLATE, we
* migrate the pages from an unaligned range (ie. pages that
* we are interested in). This will put all the pages in
* we are interested in). This will put all the pages in
* range back to page allocator as MIGRATE_ISOLATE.
*
* When this is done, we take the pages in range from page
@ -9074,9 +9108,9 @@ int alloc_contig_range(unsigned long start, unsigned long end,
*/
ret = start_isolate_page_range(pfn_max_align_down(start),
pfn_max_align_up(end), migratetype, 0);
pfn_max_align_up(end), migratetype, 0, gfp_mask);
if (ret)
return ret;
goto done;
drain_all_pages(cc.zone);
@ -9096,7 +9130,7 @@ int alloc_contig_range(unsigned long start, unsigned long end,
ret = 0;
/*
* Pages from [start, end) are within a MAX_ORDER_NR_PAGES
* Pages from [start, end) are within a pageblock_nr_pages
* aligned blocks that are marked as MIGRATE_ISOLATE. What's
* more, all pages in [start, end) are free in page allocator.
* What we are going to do is to allocate all pages from

193
mm/page_isolation.c
View File

@ -203,7 +203,7 @@ static int set_migratetype_isolate(struct page *page, int migratetype, int isol_
return -EBUSY;
}
static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
static void unset_migratetype_isolate(struct page *page, int migratetype)
{
struct zone *zone;
unsigned long flags, nr_pages;
@ -279,6 +279,166 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
return NULL;
}
/**
* isolate_single_pageblock() -- tries to isolate a pageblock that might be
* within a free or in-use page.
* @boundary_pfn: pageblock-aligned pfn that a page might cross
* @gfp_flags: GFP flags used for migrating pages
* @isolate_before: isolate the pageblock before the boundary_pfn
*
* Free and in-use pages can be as big as MAX_ORDER-1 and contain more than one
* pageblock. When not all pageblocks within a page are isolated at the same
* time, free page accounting can go wrong. For example, in the case of
* MAX_ORDER-1 = pageblock_order + 1, a MAX_ORDER-1 page has two pagelbocks.
* [ MAX_ORDER-1 ]
* [ pageblock0 | pageblock1 ]
* When either pageblock is isolated, if it is a free page, the page is not
* split into separate migratetype lists, which is supposed to; if it is an
* in-use page and freed later, __free_one_page() does not split the free page
* either. The function handles this by splitting the free page or migrating
* the in-use page then splitting the free page.
*/
static int isolate_single_pageblock(unsigned long boundary_pfn, gfp_t gfp_flags,
bool isolate_before)
{
unsigned char saved_mt;
unsigned long start_pfn;
unsigned long isolate_pageblock;
unsigned long pfn;
struct zone *zone;
VM_BUG_ON(!IS_ALIGNED(boundary_pfn, pageblock_nr_pages));
if (isolate_before)
isolate_pageblock = boundary_pfn - pageblock_nr_pages;
else
isolate_pageblock = boundary_pfn;
/*
* scan at the beginning of MAX_ORDER_NR_PAGES aligned range to avoid
* only isolating a subset of pageblocks from a bigger than pageblock
* free or in-use page. Also make sure all to-be-isolated pageblocks
* are within the same zone.
*/
zone = page_zone(pfn_to_page(isolate_pageblock));
start_pfn = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
zone->zone_start_pfn);
saved_mt = get_pageblock_migratetype(pfn_to_page(isolate_pageblock));
set_pageblock_migratetype(pfn_to_page(isolate_pageblock), MIGRATE_ISOLATE);
/*
* Bail out early when the to-be-isolated pageblock does not form
* a free or in-use page across boundary_pfn:
*
* 1. isolate before boundary_pfn: the page after is not online
* 2. isolate after boundary_pfn: the page before is not online
*
* This also ensures correctness. Without it, when isolate after
* boundary_pfn and [start_pfn, boundary_pfn) are not online,
* __first_valid_page() will return unexpected NULL in the for loop
* below.
*/
if (isolate_before) {
if (!pfn_to_online_page(boundary_pfn))
return 0;
} else {
if (!pfn_to_online_page(boundary_pfn - 1))
return 0;
}
for (pfn = start_pfn; pfn < boundary_pfn;) {
struct page *page = __first_valid_page(pfn, boundary_pfn - pfn);
VM_BUG_ON(!page);
pfn = page_to_pfn(page);
/*
* start_pfn is MAX_ORDER_NR_PAGES aligned, if there is any
* free pages in [start_pfn, boundary_pfn), its head page will
* always be in the range.
*/
if (PageBuddy(page)) {
int order = buddy_order(page);
if (pfn + (1UL << order) > boundary_pfn)
split_free_page(page, order, boundary_pfn - pfn);
pfn += (1UL << order);
continue;
}
/*
* migrate compound pages then let the free page handling code
* above do the rest. If migration is not possible, just fail.
*/
if (PageCompound(page)) {
unsigned long nr_pages = compound_nr(page);
struct page *head = compound_head(page);
unsigned long head_pfn = page_to_pfn(head);
if (head_pfn + nr_pages < boundary_pfn) {
pfn = head_pfn + nr_pages;
continue;
}
#if defined CONFIG_COMPACTION || defined CONFIG_CMA
/*
* hugetlb, lru compound (THP), and movable compound pages
* can be migrated. Otherwise, fail the isolation.
*/
if (PageHuge(page) || PageLRU(page) || __PageMovable(page)) {
int order;
unsigned long outer_pfn;
int ret;
struct compact_control cc = {
.nr_migratepages = 0,
.order = -1,
.zone = page_zone(pfn_to_page(head_pfn)),
.mode = MIGRATE_SYNC,
.ignore_skip_hint = true,
.no_set_skip_hint = true,
.gfp_mask = gfp_flags,
.alloc_contig = true,
};
INIT_LIST_HEAD(&cc.migratepages);
ret = __alloc_contig_migrate_range(&cc, head_pfn,
head_pfn + nr_pages);
if (ret)
goto failed;
/*
* reset pfn to the head of the free page, so
* that the free page handling code above can split
* the free page to the right migratetype list.
*
* head_pfn is not used here as a hugetlb page order
* can be bigger than MAX_ORDER-1, but after it is
* freed, the free page order is not. Use pfn within
* the range to find the head of the free page.
*/
order = 0;
outer_pfn = pfn;
while (!PageBuddy(pfn_to_page(outer_pfn))) {
if (++order >= MAX_ORDER) {
outer_pfn = pfn;
break;
}
outer_pfn &= ~0UL << order;
}
pfn = outer_pfn;
continue;
} else
#endif
goto failed;
}
pfn++;
}
return 0;
failed:
/* restore the original migratetype */
set_pageblock_migratetype(pfn_to_page(isolate_pageblock), saved_mt);
return -EBUSY;
}
/**
* start_isolate_page_range() - make page-allocation-type of range of pages to
* be MIGRATE_ISOLATE.
@ -293,6 +453,8 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
* and PageOffline() pages.
* REPORT_FAILURE - report details about the failure to
* isolate the range
* @gfp_flags: GFP flags used for migrating pages that sit across the
* range boundaries.
*
* 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
@ -301,6 +463,10 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
* pages in the range finally, the caller have to free all pages in the range.
* test_page_isolated() can be used for test it.
*
* The function first tries to isolate the pageblocks at the beginning and end
* of the range, since there might be pages across the range boundaries.
* Afterwards, it isolates the rest of the range.
*
* There is no high level synchronization mechanism that prevents two threads
* from trying to isolate overlapping ranges. If this happens, one thread
* will notice pageblocks in the overlapping range already set to isolate.
@ -321,21 +487,38 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
* Return: 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 migratetype, int flags)
int migratetype, int flags, gfp_t gfp_flags)
{
unsigned long pfn;
struct page *page;
int ret;
BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages));
BUG_ON(!IS_ALIGNED(end_pfn, pageblock_nr_pages));
for (pfn = start_pfn;
pfn < end_pfn;
/* isolate [start_pfn, start_pfn + pageblock_nr_pages) pageblock */
ret = isolate_single_pageblock(start_pfn, gfp_flags, false);
if (ret)
return ret;
/* isolate [end_pfn - pageblock_nr_pages, end_pfn) pageblock */
ret = isolate_single_pageblock(end_pfn, gfp_flags, true);
if (ret) {
unset_migratetype_isolate(pfn_to_page(start_pfn), migratetype);
return ret;
}
/* skip isolated pageblocks at the beginning and end */
for (pfn = start_pfn + pageblock_nr_pages;
pfn < end_pfn - pageblock_nr_pages;
pfn += pageblock_nr_pages) {
page = __first_valid_page(pfn, pageblock_nr_pages);
if (page && set_migratetype_isolate(page, migratetype, flags,
start_pfn, end_pfn)) {
undo_isolate_page_range(start_pfn, pfn, migratetype);
unset_migratetype_isolate(
pfn_to_page(end_pfn - pageblock_nr_pages),
migratetype);
return -EBUSY;
}
}
@ -346,7 +529,7 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
* Make isolated pages available again.
*/
void undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
unsigned migratetype)
int migratetype)
{
unsigned long pfn;
struct page *page;