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4cf5892495
Patch series "Add support for fast mremap".
This series speeds up the mremap(2) syscall by copying page tables at
the PMD level even for non-THP systems. There is concern that the extra
'address' argument that mremap passes to pte_alloc may do something
subtle architecture related in the future that may make the scheme not
work. Also we find that there is no point in passing the 'address' to
pte_alloc since its unused. This patch therefore removes this argument
tree-wide resulting in a nice negative diff as well. Also ensuring
along the way that the enabled architectures do not do anything funky
with the 'address' argument that goes unnoticed by the optimization.
Build and boot tested on x86-64. Build tested on arm64. The config
enablement patch for arm64 will be posted in the future after more
testing.
The changes were obtained by applying the following Coccinelle script.
(thanks Julia for answering all Coccinelle questions!).
Following fix ups were done manually:
* Removal of address argument from pte_fragment_alloc
* Removal of pte_alloc_one_fast definitions from m68k and microblaze.
// Options: --include-headers --no-includes
// Note: I split the 'identifier fn' line, so if you are manually
// running it, please unsplit it so it runs for you.
virtual patch
@pte_alloc_func_def depends on patch exists@
identifier E2;
identifier fn =~
"^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$";
type T2;
@@
fn(...
- , T2 E2
)
{ ... }
@pte_alloc_func_proto_noarg depends on patch exists@
type T1, T2, T3, T4;
identifier fn =~ "^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$";
@@
(
- T3 fn(T1, T2);
+ T3 fn(T1);
|
- T3 fn(T1, T2, T4);
+ T3 fn(T1, T2);
)
@pte_alloc_func_proto depends on patch exists@
identifier E1, E2, E4;
type T1, T2, T3, T4;
identifier fn =~
"^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$";
@@
(
- T3 fn(T1 E1, T2 E2);
+ T3 fn(T1 E1);
|
- T3 fn(T1 E1, T2 E2, T4 E4);
+ T3 fn(T1 E1, T2 E2);
)
@pte_alloc_func_call depends on patch exists@
expression E2;
identifier fn =~
"^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$";
@@
fn(...
-, E2
)
@pte_alloc_macro depends on patch exists@
identifier fn =~
"^(__pte_alloc|pte_alloc_one|pte_alloc|__pte_alloc_kernel|pte_alloc_one_kernel)$";
identifier a, b, c;
expression e;
position p;
@@
(
- #define fn(a, b, c) e
+ #define fn(a, b) e
|
- #define fn(a, b) e
+ #define fn(a) e
)
Link: http://lkml.kernel.org/r/20181108181201.88826-2-joelaf@google.com
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Suggested-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
113 lines
2.4 KiB
C
113 lines
2.4 KiB
C
/*
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* linux/arch/unicore32/include/asm/pgalloc.h
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*
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* Code specific to PKUnity SoC and UniCore ISA
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*
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* Copyright (C) 2001-2010 GUAN Xue-tao
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef __UNICORE_PGALLOC_H__
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#define __UNICORE_PGALLOC_H__
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#include <asm/pgtable-hwdef.h>
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#include <asm/processor.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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#define check_pgt_cache() do { } while (0)
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#define _PAGE_USER_TABLE (PMD_TYPE_TABLE | PMD_PRESENT)
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#define _PAGE_KERNEL_TABLE (PMD_TYPE_TABLE | PMD_PRESENT)
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extern pgd_t *get_pgd_slow(struct mm_struct *mm);
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extern void free_pgd_slow(struct mm_struct *mm, pgd_t *pgd);
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#define pgd_alloc(mm) get_pgd_slow(mm)
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#define pgd_free(mm, pgd) free_pgd_slow(mm, pgd)
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#define PGALLOC_GFP (GFP_KERNEL | __GFP_ZERO)
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/*
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* Allocate one PTE table.
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*/
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static inline pte_t *
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pte_alloc_one_kernel(struct mm_struct *mm)
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{
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pte_t *pte;
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pte = (pte_t *)__get_free_page(PGALLOC_GFP);
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if (pte)
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clean_dcache_area(pte, PTRS_PER_PTE * sizeof(pte_t));
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return pte;
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}
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static inline pgtable_t
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pte_alloc_one(struct mm_struct *mm)
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{
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struct page *pte;
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pte = alloc_pages(PGALLOC_GFP, 0);
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if (!pte)
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return NULL;
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if (!PageHighMem(pte)) {
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void *page = page_address(pte);
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clean_dcache_area(page, PTRS_PER_PTE * sizeof(pte_t));
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}
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if (!pgtable_page_ctor(pte)) {
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__free_page(pte);
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}
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return pte;
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}
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/*
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* Free one PTE table.
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*/
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static inline void pte_free_kernel(struct mm_struct *mm, pte_t *pte)
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{
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if (pte)
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free_page((unsigned long)pte);
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}
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static inline void pte_free(struct mm_struct *mm, pgtable_t pte)
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{
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pgtable_page_dtor(pte);
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__free_page(pte);
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}
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static inline void __pmd_populate(pmd_t *pmdp, unsigned long pmdval)
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{
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set_pmd(pmdp, __pmd(pmdval));
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flush_pmd_entry(pmdp);
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}
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/*
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* Populate the pmdp entry with a pointer to the pte. This pmd is part
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* of the mm address space.
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*/
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static inline void
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pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *ptep)
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{
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unsigned long pte_ptr = (unsigned long)ptep;
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/*
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* The pmd must be loaded with the physical
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* address of the PTE table
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*/
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__pmd_populate(pmdp, __pa(pte_ptr) | _PAGE_KERNEL_TABLE);
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}
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static inline void
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pmd_populate(struct mm_struct *mm, pmd_t *pmdp, pgtable_t ptep)
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{
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__pmd_populate(pmdp,
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page_to_pfn(ptep) << PAGE_SHIFT | _PAGE_USER_TABLE);
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}
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#define pmd_pgtable(pmd) pmd_page(pmd)
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#endif
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