mirror of
https://github.com/torvalds/linux.git
synced 2024-12-30 23:02:08 +00:00
4f83145721
Calls to change_protection_range() on THP can trigger, at least on x86, two TLB flushes for one page: one immediately, when pmdp_invalidate() is called by change_huge_pmd(), and then another one later (that can be batched) when change_protection_range() finishes. The first TLB flush is only necessary to prevent the dirty bit (and with a lesser importance the access bit) from changing while the PTE is modified. However, this is not necessary as the x86 CPUs set the dirty-bit atomically with an additional check that the PTE is (still) present. One caveat is Intel's Knights Landing that has a bug and does not do so. Leverage this behavior to eliminate the unnecessary TLB flush in change_huge_pmd(). Introduce a new arch specific pmdp_invalidate_ad() that only invalidates the access and dirty bit from further changes. Link: https://lkml.kernel.org/r/20220401180821.1986781-4-namit@vmware.com Signed-off-by: Nadav Amit <namit@vmware.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Andrew Cooper <andrew.cooper3@citrix.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Peter Xu <peterx@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will@kernel.org> Cc: Yu Zhao <yuzhao@google.com> Cc: Nick Piggin <npiggin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
232 lines
5.8 KiB
C
232 lines
5.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* mm/pgtable-generic.c
|
|
*
|
|
* Generic pgtable methods declared in linux/pgtable.h
|
|
*
|
|
* Copyright (C) 2010 Linus Torvalds
|
|
*/
|
|
|
|
#include <linux/pagemap.h>
|
|
#include <linux/hugetlb.h>
|
|
#include <linux/pgtable.h>
|
|
#include <linux/mm_inline.h>
|
|
#include <asm/tlb.h>
|
|
|
|
/*
|
|
* If a p?d_bad entry is found while walking page tables, report
|
|
* the error, before resetting entry to p?d_none. Usually (but
|
|
* very seldom) called out from the p?d_none_or_clear_bad macros.
|
|
*/
|
|
|
|
void pgd_clear_bad(pgd_t *pgd)
|
|
{
|
|
pgd_ERROR(*pgd);
|
|
pgd_clear(pgd);
|
|
}
|
|
|
|
#ifndef __PAGETABLE_P4D_FOLDED
|
|
void p4d_clear_bad(p4d_t *p4d)
|
|
{
|
|
p4d_ERROR(*p4d);
|
|
p4d_clear(p4d);
|
|
}
|
|
#endif
|
|
|
|
#ifndef __PAGETABLE_PUD_FOLDED
|
|
void pud_clear_bad(pud_t *pud)
|
|
{
|
|
pud_ERROR(*pud);
|
|
pud_clear(pud);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Note that the pmd variant below can't be stub'ed out just as for p4d/pud
|
|
* above. pmd folding is special and typically pmd_* macros refer to upper
|
|
* level even when folded
|
|
*/
|
|
void pmd_clear_bad(pmd_t *pmd)
|
|
{
|
|
pmd_ERROR(*pmd);
|
|
pmd_clear(pmd);
|
|
}
|
|
|
|
#ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
|
|
/*
|
|
* Only sets the access flags (dirty, accessed), as well as write
|
|
* permission. Furthermore, we know it always gets set to a "more
|
|
* permissive" setting, which allows most architectures to optimize
|
|
* this. We return whether the PTE actually changed, which in turn
|
|
* instructs the caller to do things like update__mmu_cache. This
|
|
* used to be done in the caller, but sparc needs minor faults to
|
|
* force that call on sun4c so we changed this macro slightly
|
|
*/
|
|
int ptep_set_access_flags(struct vm_area_struct *vma,
|
|
unsigned long address, pte_t *ptep,
|
|
pte_t entry, int dirty)
|
|
{
|
|
int changed = !pte_same(*ptep, entry);
|
|
if (changed) {
|
|
set_pte_at(vma->vm_mm, address, ptep, entry);
|
|
flush_tlb_fix_spurious_fault(vma, address);
|
|
}
|
|
return changed;
|
|
}
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
|
|
int ptep_clear_flush_young(struct vm_area_struct *vma,
|
|
unsigned long address, pte_t *ptep)
|
|
{
|
|
int young;
|
|
young = ptep_test_and_clear_young(vma, address, ptep);
|
|
if (young)
|
|
flush_tlb_page(vma, address);
|
|
return young;
|
|
}
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
|
|
pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
|
|
pte_t *ptep)
|
|
{
|
|
struct mm_struct *mm = (vma)->vm_mm;
|
|
pte_t pte;
|
|
pte = ptep_get_and_clear(mm, address, ptep);
|
|
if (pte_accessible(mm, pte))
|
|
flush_tlb_page(vma, address);
|
|
return pte;
|
|
}
|
|
#endif
|
|
|
|
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
|
|
|
#ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
|
|
int pmdp_set_access_flags(struct vm_area_struct *vma,
|
|
unsigned long address, pmd_t *pmdp,
|
|
pmd_t entry, int dirty)
|
|
{
|
|
int changed = !pmd_same(*pmdp, entry);
|
|
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
|
|
if (changed) {
|
|
set_pmd_at(vma->vm_mm, address, pmdp, entry);
|
|
flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
|
|
}
|
|
return changed;
|
|
}
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
|
|
int pmdp_clear_flush_young(struct vm_area_struct *vma,
|
|
unsigned long address, pmd_t *pmdp)
|
|
{
|
|
int young;
|
|
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
|
|
young = pmdp_test_and_clear_young(vma, address, pmdp);
|
|
if (young)
|
|
flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
|
|
return young;
|
|
}
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
|
|
pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
|
|
pmd_t *pmdp)
|
|
{
|
|
pmd_t pmd;
|
|
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
|
|
VM_BUG_ON(pmd_present(*pmdp) && !pmd_trans_huge(*pmdp) &&
|
|
!pmd_devmap(*pmdp));
|
|
pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
|
|
flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
|
|
return pmd;
|
|
}
|
|
|
|
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
|
|
pud_t pudp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
|
|
pud_t *pudp)
|
|
{
|
|
pud_t pud;
|
|
|
|
VM_BUG_ON(address & ~HPAGE_PUD_MASK);
|
|
VM_BUG_ON(!pud_trans_huge(*pudp) && !pud_devmap(*pudp));
|
|
pud = pudp_huge_get_and_clear(vma->vm_mm, address, pudp);
|
|
flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
|
|
return pud;
|
|
}
|
|
#endif
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
|
|
void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
|
|
pgtable_t pgtable)
|
|
{
|
|
assert_spin_locked(pmd_lockptr(mm, pmdp));
|
|
|
|
/* FIFO */
|
|
if (!pmd_huge_pte(mm, pmdp))
|
|
INIT_LIST_HEAD(&pgtable->lru);
|
|
else
|
|
list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru);
|
|
pmd_huge_pte(mm, pmdp) = pgtable;
|
|
}
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
|
|
/* no "address" argument so destroys page coloring of some arch */
|
|
pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
|
|
{
|
|
pgtable_t pgtable;
|
|
|
|
assert_spin_locked(pmd_lockptr(mm, pmdp));
|
|
|
|
/* FIFO */
|
|
pgtable = pmd_huge_pte(mm, pmdp);
|
|
pmd_huge_pte(mm, pmdp) = list_first_entry_or_null(&pgtable->lru,
|
|
struct page, lru);
|
|
if (pmd_huge_pte(mm, pmdp))
|
|
list_del(&pgtable->lru);
|
|
return pgtable;
|
|
}
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PMDP_INVALIDATE
|
|
pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
|
|
pmd_t *pmdp)
|
|
{
|
|
pmd_t old = pmdp_establish(vma, address, pmdp, pmd_mkinvalid(*pmdp));
|
|
flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
|
|
return old;
|
|
}
|
|
#endif
|
|
|
|
#ifndef __HAVE_ARCH_PMDP_INVALIDATE_AD
|
|
pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address,
|
|
pmd_t *pmdp)
|
|
{
|
|
return pmdp_invalidate(vma, address, pmdp);
|
|
}
|
|
#endif
|
|
|
|
#ifndef pmdp_collapse_flush
|
|
pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
|
|
pmd_t *pmdp)
|
|
{
|
|
/*
|
|
* pmd and hugepage pte format are same. So we could
|
|
* use the same function.
|
|
*/
|
|
pmd_t pmd;
|
|
|
|
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
|
|
VM_BUG_ON(pmd_trans_huge(*pmdp));
|
|
pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
|
|
|
|
/* collapse entails shooting down ptes not pmd */
|
|
flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
|
|
return pmd;
|
|
}
|
|
#endif
|
|
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
|