Normal page init path frees pages during the boot in MAX_ORDER chunks,
but deferred page init path does it in pageblock blocks.
Change deferred page init path to work in MAX_ORDER blocks.
For cases when pageblock is larger than MAX_ORDER, set migrate type to
MIGRATE_MOVABLE for all pageblocks covered by the page.
Signed-off-by: Kirill A. Shutemov <[email protected]>
---
Note: the patch depends on the new definiton of MAX_ORDER.
---
include/linux/mmzone.h | 2 ++
mm/page_alloc.c | 19 ++++++++++---------
2 files changed, 12 insertions(+), 9 deletions(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 96599cb9eb62..f53fe3a7ca45 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -32,6 +32,8 @@
#endif
#define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
+#define IS_MAX_ORDER_ALIGNED(pfn) IS_ALIGNED(pfn, MAX_ORDER_NR_PAGES)
+
/*
* PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed
* costly to service. That is between allocation orders which should
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 87d760236dba..fc02a243425d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1875,9 +1875,10 @@ static void __init deferred_free_range(unsigned long pfn,
page = pfn_to_page(pfn);
/* Free a large naturally-aligned chunk if possible */
- if (nr_pages == pageblock_nr_pages && pageblock_aligned(pfn)) {
- set_pageblock_migratetype(page, MIGRATE_MOVABLE);
- __free_pages_core(page, pageblock_order);
+ if (nr_pages == MAX_ORDER_NR_PAGES && IS_MAX_ORDER_ALIGNED(pfn)) {
+ for (i = 0; i < nr_pages; i += pageblock_nr_pages)
+ set_pageblock_migratetype(page + i, MIGRATE_MOVABLE);
+ __free_pages_core(page, MAX_ORDER);
return;
}
@@ -1901,19 +1902,19 @@ static inline void __init pgdat_init_report_one_done(void)
/*
* Returns true if page needs to be initialized or freed to buddy allocator.
*
- * We check if a current large page is valid by only checking the validity
+ * We check if a current MAX_ORDER block is valid by only checking the validity
* of the head pfn.
*/
static inline bool __init deferred_pfn_valid(unsigned long pfn)
{
- if (pageblock_aligned(pfn) && !pfn_valid(pfn))
+ if (IS_MAX_ORDER_ALIGNED(pfn) && !pfn_valid(pfn))
return false;
return true;
}
/*
* Free pages to buddy allocator. Try to free aligned pages in
- * pageblock_nr_pages sizes.
+ * MAX_ORDER_NR_PAGES sizes.
*/
static void __init deferred_free_pages(unsigned long pfn,
unsigned long end_pfn)
@@ -1924,7 +1925,7 @@ static void __init deferred_free_pages(unsigned long pfn,
if (!deferred_pfn_valid(pfn)) {
deferred_free_range(pfn - nr_free, nr_free);
nr_free = 0;
- } else if (pageblock_aligned(pfn)) {
+ } else if (IS_MAX_ORDER_ALIGNED(pfn)) {
deferred_free_range(pfn - nr_free, nr_free);
nr_free = 1;
} else {
@@ -1937,7 +1938,7 @@ static void __init deferred_free_pages(unsigned long pfn,
/*
* Initialize struct pages. We minimize pfn page lookups and scheduler checks
- * by performing it only once every pageblock_nr_pages.
+ * by performing it only once every MAX_ORDER_NR_PAGES.
* Return number of pages initialized.
*/
static unsigned long __init deferred_init_pages(struct zone *zone,
@@ -1953,7 +1954,7 @@ static unsigned long __init deferred_init_pages(struct zone *zone,
if (!deferred_pfn_valid(pfn)) {
page = NULL;
continue;
- } else if (!page || pageblock_aligned(pfn)) {
+ } else if (!page || IS_MAX_ORDER_ALIGNED(pfn)) {
page = pfn_to_page(pfn);
} else {
page++;
--
2.39.2
On 17.03.23 16:35, Kirill A. Shutemov wrote:
> Normal page init path frees pages during the boot in MAX_ORDER chunks,
> but deferred page init path does it in pageblock blocks.
>
> Change deferred page init path to work in MAX_ORDER blocks.
>
> For cases when pageblock is larger than MAX_ORDER, set migrate type to
> MIGRATE_MOVABLE for all pageblocks covered by the page.
See
commit b3d40a2b6d10c9d0424d2b398bf962fb6adad87e
Author: David Hildenbrand <[email protected]>
Date: Tue Mar 22 14:43:20 2022 -0700
mm: enforce pageblock_order < MAX_ORDER
Some places in the kernel don't really expect pageblock_order >=
MAX_ORDER, and it looks like this is only possible in corner cases:
1) CONFIG_DEFERRED_STRUCT_PAGE_INIT we'll end up freeing pageblock_order
pages via __free_pages_core(), which cannot possibly work.
...
How should it still happen?
--
Thanks,
David / dhildenb
On Fri, Mar 17, 2023 at 06:50:17PM +0100, David Hildenbrand wrote:
> On 17.03.23 16:35, Kirill A. Shutemov wrote:
> > Normal page init path frees pages during the boot in MAX_ORDER chunks,
> > but deferred page init path does it in pageblock blocks.
> >
> > Change deferred page init path to work in MAX_ORDER blocks.
> >
> > For cases when pageblock is larger than MAX_ORDER, set migrate type to
> > MIGRATE_MOVABLE for all pageblocks covered by the page.
>
> See
>
> commit b3d40a2b6d10c9d0424d2b398bf962fb6adad87e
> Author: David Hildenbrand <[email protected]>
> Date: Tue Mar 22 14:43:20 2022 -0700
>
> mm: enforce pageblock_order < MAX_ORDER
> Some places in the kernel don't really expect pageblock_order >=
> MAX_ORDER, and it looks like this is only possible in corner cases:
> 1) CONFIG_DEFERRED_STRUCT_PAGE_INIT we'll end up freeing pageblock_order
> pages via __free_pages_core(), which cannot possibly work.
>
> ...
>
> How should it still happen?
I got the sentence backwards. It suppose to be
For cases when MAX_ORDER is larger than pageblock, set migrate type to
MIGRATE_MOVABLE for all pageblocks covered by the page.
--
Kiryl Shutsemau / Kirill A. Shutemov
On Fri, Mar 17, 2023 at 06:35:01PM +0300, Kirill A. Shutemov wrote:
> Normal page init path frees pages during the boot in MAX_ORDER chunks,
> but deferred page init path does it in pageblock blocks.
>
> Change deferred page init path to work in MAX_ORDER blocks.
>
> For cases when pageblock is larger than MAX_ORDER, set migrate type to
> MIGRATE_MOVABLE for all pageblocks covered by the page.
>
The problem with the sentence was pointed out already.
> Signed-off-by: Kirill A. Shutemov <[email protected]>
Otherwise;
Acked-by: Mel Gorman <[email protected]>
--
Mel Gorman
SUSE Labs