diff mbox series

[RFC,04/15] mm: prevent pageblock size being larger than section size.

Message ID 20210805190253.2795604-5-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. 5, 2021, 7:02 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 973fd731a520..4277b4267767 100644
--- a/include/linux/pageblock-flags.h
+++ b/include/linux/pageblock-flags.h
@@ -44,8 +44,11 @@  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-1)
+/*
+ * 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-1))
 
 #endif /* CONFIG_HUGETLB_PAGE */