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Message-Id: <20200428194449.22615-2-willy@infradead.org>
Date: Tue, 28 Apr 2020 12:44:43 -0700
From: Matthew Wilcox <willy@...radead.org>
To: linux-mm@...ck.org
Cc: "Matthew Wilcox (Oracle)" <willy@...radead.org>,
linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
Will Deacon <will@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
Russell King <linux@...linux.org.uk>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
linux-m68k@...ts.linux-m68k.org
Subject: [PATCH 1/7] mm: Document x86 uses a linked list of pgds
From: "Matthew Wilcox (Oracle)" <willy@...radead.org>
x86 uses page->lru of the pages used for pgds, but that's not immediately
obvious to anyone looking to make changes. Add a struct list_head to
the union so it's clearly in use for pgds.
Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
include/linux/mm_types.h | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 4aba6c0c2ba8..9bb34e2cd5a5 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -142,8 +142,13 @@ struct page {
struct list_head deferred_list;
};
struct { /* Page table pages */
- unsigned long _pt_pad_1; /* compound_head */
- pgtable_t pmd_huge_pte; /* protected by page->ptl */
+ union {
+ struct list_head pgd_list; /* x86 */
+ struct {
+ unsigned long _pt_pad_1;
+ pgtable_t pmd_huge_pte;
+ };
+ };
unsigned long _pt_pad_2; /* mapping */
union {
struct mm_struct *pt_mm; /* x86 pgds only */
--
2.26.2
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