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From: James Houghton <jthoughton@google.com>
To: Mike Kravetz <mike.kravetz@oracle.com>,
	Hugh Dickins <hughd@google.com>,
	 Muchun Song <songmuchun@bytedance.com>,
	Peter Xu <peterx@redhat.com>,
	 "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	David Hildenbrand <david@redhat.com>,
	 David Rientjes <rientjes@google.com>,
	Axel Rasmussen <axelrasmussen@google.com>,
	 Jiaqi Yan <jiaqiyan@google.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	 James Houghton <jthoughton@google.com>
Subject: [PATCH 2/2] mm: rmap: increase COMPOUND_MAPPED to support 512G HugeTLB pages
Date: Mon,  6 Mar 2023 23:00:04 +0000	[thread overview]
Message-ID: <20230306230004.1387007-3-jthoughton@google.com> (raw)
In-Reply-To: <20230306230004.1387007-1-jthoughton@google.com>

Some architectures may want to support 512G HugeTLB pages in the future.
Adjust COMPOUND_MAPPED to support this page size.

Signed-off-by: James Houghton <jthoughton@google.com>

diff --git a/mm/internal.h b/mm/internal.h
index 400451a4dd49..994381fd5155 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -53,11 +53,11 @@ struct folio_batch;
 void page_writeback_init(void);
 
 /*
- * If a 16GB hugetlb folio were mapped by PTEs of all of its 4kB pages,
- * its nr_pages_mapped would be 0x400000: choose the COMPOUND_MAPPED bit
- * above that range, instead of 2*(PMD_SIZE/PAGE_SIZE).
+ * If a 512G hugetlb folio were mapped by PTEs of all of its 4kB pages,
+ * its nr_pages_mapped would be 2^27 (0x8000000): choose the COMPOUND_MAPPED bit
+ * above that range.
  */
-#define COMPOUND_MAPPED		0x800000
+#define COMPOUND_MAPPED		(1 << 28)
 #define FOLIO_PAGES_MAPPED	(COMPOUND_MAPPED - 1)
 
 /*
-- 
2.40.0.rc0.216.gc4246ad0f0-goog



  parent reply	other threads:[~2023-03-06 23:00 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-06 23:00 [PATCH 0/2] mm: rmap: merge HugeTLB mapcount logic with THPs James Houghton
2023-03-06 23:00 ` [PATCH 1/2] mm: rmap: make hugetlb pages participate in _nr_pages_mapped James Houghton
2023-03-07 21:54   ` Mike Kravetz
2023-03-08  0:36     ` James Houghton
2023-03-08 21:56       ` Peter Xu
2023-03-09 19:58         ` James Houghton
2023-03-06 23:00 ` James Houghton [this message]
2023-03-08 22:10 ` [PATCH 0/2] mm: rmap: merge HugeTLB mapcount logic with THPs Peter Xu
2023-03-09 18:05   ` James Houghton
2023-03-09 19:29     ` Peter Xu

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