The patch titled
Subject: x86/pgtable: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE
has been added to the -mm tree. Its filename is
x86-pgtable-support-__have_arch_pte_swp_exclusive.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/x86-pgtable-support-__have_arch_pte_swp_exclusive.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/x86-pgtable-support-__have_arch_pte_swp_exclusive.patch
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------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: x86/pgtable: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE
Let's use bit 3 to remember PG_anon_exclusive in swap ptes.
Link: https://lkml.kernel.org/r/20220329164329.208407-4-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Don Dutile <ddutile@xxxxxxxxxx>
Cc: Gerald Schaefer <gerald.schaefer@xxxxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Liang Zhang <zhangliang5@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: Nadav Amit <namit@xxxxxxxxxx>
Cc: Oded Gabbay <oded.gabbay@xxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Pedro Demarchi Gomes <pedrodemargomes@xxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/pgtable.h | 16 ++++++++++++++++
arch/x86/include/asm/pgtable_64.h | 4 +++-
arch/x86/include/asm/pgtable_types.h | 5 +++++
3 files changed, 24 insertions(+), 1 deletion(-)
--- a/arch/x86/include/asm/pgtable_64.h~x86-pgtable-support-__have_arch_pte_swp_exclusive
+++ a/arch/x86/include/asm/pgtable_64.h
@@ -186,7 +186,7 @@ static inline void native_pgd_clear(pgd_
*
* | ... | 11| 10| 9|8|7|6|5| 4| 3|2| 1|0| <- bit number
* | ... |SW3|SW2|SW1|G|L|D|A|CD|WT|U| W|P| <- bit names
- * | TYPE (59-63) | ~OFFSET (9-58) |0|0|X|X| X| X|F|SD|0| <- swp entry
+ * | TYPE (59-63) | ~OFFSET (9-58) |0|0|X|X| X| E|F|SD|0| <- swp entry
*
* G (8) is aliased and used as a PROT_NONE indicator for
* !present ptes. We need to start storing swap entries above
@@ -203,6 +203,8 @@ static inline void native_pgd_clear(pgd_
* F (2) in swp entry is used to record when a pagetable is
* writeprotected by userfaultfd WP support.
*
+ * E (3) in swp entry is used to rememeber PG_anon_exclusive.
+ *
* Bit 7 in swp entry should be 0 because pmd_present checks not only P,
* but also L and G.
*
--- a/arch/x86/include/asm/pgtable.h~x86-pgtable-support-__have_arch_pte_swp_exclusive
+++ a/arch/x86/include/asm/pgtable.h
@@ -1292,6 +1292,22 @@ static inline void update_mmu_cache_pud(
{
}
+#define __HAVE_ARCH_PTE_SWP_EXCLUSIVE
+static inline pte_t pte_swp_mkexclusive(pte_t pte)
+{
+ return pte_set_flags(pte, _PAGE_SWP_EXCLUSIVE);
+}
+
+static inline int pte_swp_exclusive(pte_t pte)
+{
+ return pte_flags(pte) & _PAGE_SWP_EXCLUSIVE;
+}
+
+static inline pte_t pte_swp_clear_exclusive(pte_t pte)
+{
+ return pte_clear_flags(pte, _PAGE_SWP_EXCLUSIVE);
+}
+
#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
static inline pte_t pte_swp_mksoft_dirty(pte_t pte)
{
--- a/arch/x86/include/asm/pgtable_types.h~x86-pgtable-support-__have_arch_pte_swp_exclusive
+++ a/arch/x86/include/asm/pgtable_types.h
@@ -84,6 +84,11 @@
#endif
/*
+ * We borrow bit 3 to remember PG_anon_exclusive.
+ */
+#define _PAGE_SWP_EXCLUSIVE _PAGE_PWT
+
+/*
* Tracking soft dirty bit when a page goes to a swap is tricky.
* We need a bit which can be stored in pte _and_ not conflict
* with swap entry format. On x86 bits 1-4 are *not* involved
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-rmap-fix-missing-swap_free-in-try_to_unmap-after-arch_unmap_one-failed.patch
mm-hugetlb-take-src_mm-write_protect_seq-in-copy_hugetlb_page_range.patch
mm-memory-slightly-simplify-copy_present_pte.patch
mm-rmap-split-page_dup_rmap-into-page_dup_file_rmap-and-page_try_dup_anon_rmap.patch
mm-rmap-convert-rmap-flags-to-a-proper-distinct-rmap_t-type.patch
mm-rmap-remove-do_page_add_anon_rmap.patch
mm-rmap-pass-rmap-flags-to-hugepage_add_anon_rmap.patch
mm-rmap-drop-compound-parameter-from-page_add_new_anon_rmap.patch
mm-rmap-use-page_move_anon_rmap-when-reusing-a-mapped-pageanon-page-exclusively.patch
mm-huge_memory-remove-outdated-vm_warn_on_once_page-from-unmap_page.patch
mm-page-flags-reuse-pg_mappedtodisk-as-pg_anon_exclusive-for-pageanon-pages.patch
mm-remember-exclusively-mapped-anonymous-pages-with-pg_anon_exclusive.patch
mm-gup-disallow-follow_pagefoll_pin.patch
mm-support-gup-triggered-unsharing-of-anonymous-pages.patch
mm-gup-trigger-fault_flag_unshare-when-r-o-pinning-a-possibly-shared-anonymous-page.patch
mm-gup-sanity-check-with-config_debug_vm-that-anonymous-pages-are-exclusive-when-unpinning.patch
mm-swap-remember-pg_anon_exclusive-via-a-swp-pte-bit.patch
mm-debug_vm_pgtable-add-tests-for-__have_arch_pte_swp_exclusive.patch
x86-pgtable-support-__have_arch_pte_swp_exclusive.patch
arm64-pgtable-support-__have_arch_pte_swp_exclusive.patch
s390-pgtable-cleanup-description-of-swp-pte-layout.patch
s390-pgtable-support-__have_arch_pte_swp_exclusive.patch
powerpc-pgtable-remove-_page_bit_swap_type-for-book3s.patch
powerpc-pgtable-support-__have_arch_pte_swp_exclusive-for-book3s.patch
