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![Mike Rapoport](/assets/img/avatar_default.png)
Patch series "mm: consolidate definitions of page table accessors", v2. The low level page table accessors (pXY_index(), pXY_offset()) are duplicated across all architectures and sometimes more than once. For instance, we have 31 definition of pgd_offset() for 25 supported architectures. Most of these definitions are actually identical and typically it boils down to, e.g. static inline unsigned long pmd_index(unsigned long address) { return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1); } static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address) { return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address); } These definitions can be shared among 90% of the arches provided XYZ_SHIFT, PTRS_PER_XYZ and xyz_page_vaddr() are defined. For architectures that really need a custom version there is always possibility to override the generic version with the usual ifdefs magic. These patches introduce include/linux/pgtable.h that replaces include/asm-generic/pgtable.h and add the definitions of the page table accessors to the new header. This patch (of 12): The linux/mm.h header includes <asm/pgtable.h> to allow inlining of the functions involving page table manipulations, e.g. pte_alloc() and pmd_alloc(). So, there is no point to explicitly include <asm/pgtable.h> in the files that include <linux/mm.h>. The include statements in such cases are remove with a simple loop: for f in $(git grep -l "include <linux/mm.h>") ; do sed -i -e '/include <asm\/pgtable.h>/ d' $f done Signed-off-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Cain <bcain@codeaurora.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Chris Zankel <chris@zankel.net> Cc: "David S. Miller" <davem@davemloft.net> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greentime Hu <green.hu@gmail.com> Cc: Greg Ungerer <gerg@linux-m68k.org> Cc: Guan Xuetao <gxt@pku.edu.cn> Cc: Guo Ren <guoren@kernel.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ley Foon Tan <ley.foon.tan@intel.com> Cc: Mark Salter <msalter@redhat.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Michal Simek <monstr@monstr.eu> Cc: Mike Rapoport <rppt@kernel.org> Cc: Nick Hu <nickhu@andestech.com> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Richard Weinberger <richard@nod.at> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Stafford Horne <shorne@gmail.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Tony Luck <tony.luck@intel.com> Cc: Vincent Chen <deanbo422@gmail.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Link: http://lkml.kernel.org/r/20200514170327.31389-1-rppt@kernel.org Link: http://lkml.kernel.org/r/20200514170327.31389-2-rppt@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
117 lines
2.7 KiB
C
117 lines
2.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2014 Davidlohr Bueso.
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*/
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#include <linux/sched/signal.h>
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#include <linux/sched/task.h>
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#include <linux/mm.h>
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#include <linux/vmacache.h>
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/*
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* Hash based on the pmd of addr if configured with MMU, which provides a good
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* hit rate for workloads with spatial locality. Otherwise, use pages.
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*/
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#ifdef CONFIG_MMU
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#define VMACACHE_SHIFT PMD_SHIFT
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#else
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#define VMACACHE_SHIFT PAGE_SHIFT
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#endif
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#define VMACACHE_HASH(addr) ((addr >> VMACACHE_SHIFT) & VMACACHE_MASK)
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/*
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* This task may be accessing a foreign mm via (for example)
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* get_user_pages()->find_vma(). The vmacache is task-local and this
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* task's vmacache pertains to a different mm (ie, its own). There is
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* nothing we can do here.
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*
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* Also handle the case where a kernel thread has adopted this mm via use_mm().
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* That kernel thread's vmacache is not applicable to this mm.
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*/
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static inline bool vmacache_valid_mm(struct mm_struct *mm)
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{
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return current->mm == mm && !(current->flags & PF_KTHREAD);
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}
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void vmacache_update(unsigned long addr, struct vm_area_struct *newvma)
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{
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if (vmacache_valid_mm(newvma->vm_mm))
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current->vmacache.vmas[VMACACHE_HASH(addr)] = newvma;
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}
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static bool vmacache_valid(struct mm_struct *mm)
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{
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struct task_struct *curr;
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if (!vmacache_valid_mm(mm))
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return false;
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curr = current;
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if (mm->vmacache_seqnum != curr->vmacache.seqnum) {
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/*
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* First attempt will always be invalid, initialize
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* the new cache for this task here.
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*/
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curr->vmacache.seqnum = mm->vmacache_seqnum;
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vmacache_flush(curr);
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return false;
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}
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return true;
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}
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struct vm_area_struct *vmacache_find(struct mm_struct *mm, unsigned long addr)
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{
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int idx = VMACACHE_HASH(addr);
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int i;
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count_vm_vmacache_event(VMACACHE_FIND_CALLS);
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if (!vmacache_valid(mm))
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return NULL;
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for (i = 0; i < VMACACHE_SIZE; i++) {
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struct vm_area_struct *vma = current->vmacache.vmas[idx];
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if (vma) {
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#ifdef CONFIG_DEBUG_VM_VMACACHE
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if (WARN_ON_ONCE(vma->vm_mm != mm))
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break;
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#endif
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if (vma->vm_start <= addr && vma->vm_end > addr) {
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count_vm_vmacache_event(VMACACHE_FIND_HITS);
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return vma;
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}
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}
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if (++idx == VMACACHE_SIZE)
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idx = 0;
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}
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return NULL;
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}
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#ifndef CONFIG_MMU
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struct vm_area_struct *vmacache_find_exact(struct mm_struct *mm,
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unsigned long start,
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unsigned long end)
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{
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int idx = VMACACHE_HASH(start);
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int i;
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count_vm_vmacache_event(VMACACHE_FIND_CALLS);
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if (!vmacache_valid(mm))
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return NULL;
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for (i = 0; i < VMACACHE_SIZE; i++) {
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struct vm_area_struct *vma = current->vmacache.vmas[idx];
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if (vma && vma->vm_start == start && vma->vm_end == end) {
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count_vm_vmacache_event(VMACACHE_FIND_HITS);
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return vma;
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}
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if (++idx == VMACACHE_SIZE)
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idx = 0;
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}
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return NULL;
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}
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#endif
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