On 11/27/20 3:19 PM, Muchun Song wrote:
Current pageblock isolation logic could isolate each pageblock individually
since commit d9dddbf55667 ("mm/page_alloc: prevent merging between isolated
and other pageblocks"). So we not need to concern about page allocator
merges buddies from different pageblocks and changes MIGRATE_ISOLATE to
some other migration type.
Yeah, that should be the case now.
Signed-off-by: Muchun Song <songmuc...@bytedance.com>
---
mm/page_alloc.c | 26 ++++++++------------------
1 file changed, 8 insertions(+), 18 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index cefbef32bf4a..608a2c2b8ab7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8313,16 +8313,14 @@ struct page *has_unmovable_pages(struct zone *zone,
struct page *page,
}
#ifdef CONFIG_CONTIG_ALLOC
-static unsigned long pfn_max_align_down(unsigned long pfn)
+static unsigned long pfn_align_down(unsigned long pfn)
{
- return pfn & ~(max_t(unsigned long, MAX_ORDER_NR_PAGES,
- pageblock_nr_pages) - 1);
+ return pfn & ~(pageblock_nr_pages - 1);
}
-static unsigned long pfn_max_align_up(unsigned long pfn)
+static unsigned long pfn_align_up(unsigned long pfn)
{
- return ALIGN(pfn, max_t(unsigned long, MAX_ORDER_NR_PAGES,
- pageblock_nr_pages));
+ return ALIGN(pfn, pageblock_nr_pages);
}
How bout just removing these wrappers completely and using ALIGN and ALIGN_DOWN
directly, as there are just two uses for each?
/* [start, end) must belong to a single zone. */
@@ -8415,14 +8413,6 @@ int alloc_contig_range(unsigned long start, unsigned
long end,
INIT_LIST_HEAD(&cc.migratepages);
/*
- * 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.
- *
* 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
@@ -8438,8 +8428,8 @@ int alloc_contig_range(unsigned long start, unsigned long
end,
* put back to page allocator so that buddy can use them.
*/
- ret = start_isolate_page_range(pfn_max_align_down(start),
- pfn_max_align_up(end), migratetype, 0);
+ ret = start_isolate_page_range(pfn_align_down(start), pfn_align_up(end),
+ migratetype, 0);
if (ret)
return ret;
@@ -8522,8 +8512,8 @@ int alloc_contig_range(unsigned long start, unsigned long end,
free_contig_range(end, outer_end - end);
done:
- undo_isolate_page_range(pfn_max_align_down(start),
- pfn_max_align_up(end), migratetype);
+ undo_isolate_page_range(pfn_align_down(start), pfn_align_up(end),
+ migratetype);
return ret;
}
EXPORT_SYMBOL(alloc_contig_range);
