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[RFC,v2,05/12] mm: prevent pageblock size being larger than section size.

Message ID 20220811231643.1012912-6-zi.yan@sent.com (mailing list archive)
State New
Headers show
Series Make MAX_ORDER adjustable as a kernel boot time parameter. | expand

Commit Message

Zi Yan Aug. 11, 2022, 11:16 p.m. UTC
From: Zi Yan <ziy@nvidia.com>

Only physical pages from a section can be guaranteed to be contiguous
and so far a pageblock can only group contiguous physical pages by
design. Set pageblock_order properly to prevent pageblock going beyond
section size.

Signed-off-by: Zi Yan <ziy@nvidia.com>
Cc: Wei Yang <richard.weiyang@linux.alibaba.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
---
 include/linux/pageblock-flags.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)
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Patch

diff --git a/include/linux/pageblock-flags.h b/include/linux/pageblock-flags.h
index 358b871b07ca..2679b2b4c079 100644
--- a/include/linux/pageblock-flags.h
+++ b/include/linux/pageblock-flags.h
@@ -47,8 +47,11 @@  extern unsigned int pageblock_order;
 
 #else /* CONFIG_HUGETLB_PAGE */
 
-/* If huge pages are not used, group by MAX_ORDER_NR_PAGES */
-#define pageblock_order		MAX_ORDER
+/*
+ * If huge pages are not used, group by MAX_ORDER_NR_PAGES or
+ * PAGES_PER_SECTION when MAX_ORDER_NR_PAGES is larger.
+ */
+#define pageblock_order		(min(PFN_SECTION_SHIFT, MAX_ORDER))
 
 #endif /* CONFIG_HUGETLB_PAGE */