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Subject[PATCH RFC 5/5] mm: remove unused savedwrite infrastructure
Date
NUMA hinting no longer uses savedwrite, let's rip it out.

... and while at it, drop __pte_write() and __pmd_write() on ppc64.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/powerpc/include/asm/book3s/64/pgtable.h | 80 +-------------------
arch/powerpc/kvm/book3s_hv_rm_mmu.c | 2 +-
include/linux/pgtable.h | 24 ------
mm/debug_vm_pgtable.c | 32 --------
4 files changed, 5 insertions(+), 133 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index 392ff48f77df..b3ddc34d71c1 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -418,35 +418,9 @@ static inline int __ptep_test_and_clear_young(struct mm_struct *mm,
#define __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
#define pmdp_clear_flush_young pmdp_test_and_clear_young

-static inline int __pte_write(pte_t pte)
-{
- return !!(pte_raw(pte) & cpu_to_be64(_PAGE_WRITE));
-}
-
-#ifdef CONFIG_NUMA_BALANCING
-#define pte_savedwrite pte_savedwrite
-static inline bool pte_savedwrite(pte_t pte)
-{
- /*
- * Saved write ptes are prot none ptes that doesn't have
- * privileged bit sit. We mark prot none as one which has
- * present and pviliged bit set and RWX cleared. To mark
- * protnone which used to have _PAGE_WRITE set we clear
- * the privileged bit.
- */
- return !(pte_raw(pte) & cpu_to_be64(_PAGE_RWX | _PAGE_PRIVILEGED));
-}
-#else
-#define pte_savedwrite pte_savedwrite
-static inline bool pte_savedwrite(pte_t pte)
-{
- return false;
-}
-#endif
-
static inline int pte_write(pte_t pte)
{
- return __pte_write(pte) || pte_savedwrite(pte);
+ return !!(pte_raw(pte) & cpu_to_be64(_PAGE_WRITE));
}

static inline int pte_read(pte_t pte)
@@ -458,24 +432,16 @@ static inline int pte_read(pte_t pte)
static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
- if (__pte_write(*ptep))
+ if (pte_write(*ptep))
pte_update(mm, addr, ptep, _PAGE_WRITE, 0, 0);
- else if (unlikely(pte_savedwrite(*ptep)))
- pte_update(mm, addr, ptep, 0, _PAGE_PRIVILEGED, 0);
}

#define __HAVE_ARCH_HUGE_PTEP_SET_WRPROTECT
static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
{
- /*
- * We should not find protnone for hugetlb, but this complete the
- * interface.
- */
- if (__pte_write(*ptep))
+ if (pte_write(*ptep))
pte_update(mm, addr, ptep, _PAGE_WRITE, 0, 1);
- else if (unlikely(pte_savedwrite(*ptep)))
- pte_update(mm, addr, ptep, 0, _PAGE_PRIVILEGED, 1);
}

#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
@@ -552,36 +518,6 @@ static inline int pte_protnone(pte_t pte)
return (pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT | _PAGE_PTE | _PAGE_RWX)) ==
cpu_to_be64(_PAGE_PRESENT | _PAGE_PTE);
}
-
-#define pte_mk_savedwrite pte_mk_savedwrite
-static inline pte_t pte_mk_savedwrite(pte_t pte)
-{
- /*
- * Used by Autonuma subsystem to preserve the write bit
- * while marking the pte PROT_NONE. Only allow this
- * on PROT_NONE pte
- */
- VM_BUG_ON((pte_raw(pte) & cpu_to_be64(_PAGE_PRESENT | _PAGE_RWX | _PAGE_PRIVILEGED)) !=
- cpu_to_be64(_PAGE_PRESENT | _PAGE_PRIVILEGED));
- return __pte_raw(pte_raw(pte) & cpu_to_be64(~_PAGE_PRIVILEGED));
-}
-
-#define pte_clear_savedwrite pte_clear_savedwrite
-static inline pte_t pte_clear_savedwrite(pte_t pte)
-{
- /*
- * Used by KSM subsystem to make a protnone pte readonly.
- */
- VM_BUG_ON(!pte_protnone(pte));
- return __pte_raw(pte_raw(pte) | cpu_to_be64(_PAGE_PRIVILEGED));
-}
-#else
-#define pte_clear_savedwrite pte_clear_savedwrite
-static inline pte_t pte_clear_savedwrite(pte_t pte)
-{
- VM_WARN_ON(1);
- return __pte_raw(pte_raw(pte) & cpu_to_be64(~_PAGE_WRITE));
-}
#endif /* CONFIG_NUMA_BALANCING */

static inline bool pte_hw_valid(pte_t pte)
@@ -658,8 +594,6 @@ static inline unsigned long pte_pfn(pte_t pte)
/* Generic modifiers for PTE bits */
static inline pte_t pte_wrprotect(pte_t pte)
{
- if (unlikely(pte_savedwrite(pte)))
- return pte_clear_savedwrite(pte);
return __pte_raw(pte_raw(pte) & cpu_to_be64(~_PAGE_WRITE));
}

@@ -1156,8 +1090,6 @@ static inline pte_t *pmdp_ptep(pmd_t *pmd)
#define pmd_mkclean(pmd) pte_pmd(pte_mkclean(pmd_pte(pmd)))
#define pmd_mkyoung(pmd) pte_pmd(pte_mkyoung(pmd_pte(pmd)))
#define pmd_mkwrite(pmd) pte_pmd(pte_mkwrite(pmd_pte(pmd)))
-#define pmd_mk_savedwrite(pmd) pte_pmd(pte_mk_savedwrite(pmd_pte(pmd)))
-#define pmd_clear_savedwrite(pmd) pte_pmd(pte_clear_savedwrite(pmd_pte(pmd)))

#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY
#define pmd_soft_dirty(pmd) pte_soft_dirty(pmd_pte(pmd))
@@ -1179,8 +1111,6 @@ static inline int pmd_protnone(pmd_t pmd)
#endif /* CONFIG_NUMA_BALANCING */

#define pmd_write(pmd) pte_write(pmd_pte(pmd))
-#define __pmd_write(pmd) __pte_write(pmd_pte(pmd))
-#define pmd_savedwrite(pmd) pte_savedwrite(pmd_pte(pmd))

#define pmd_access_permitted pmd_access_permitted
static inline bool pmd_access_permitted(pmd_t pmd, bool write)
@@ -1258,10 +1188,8 @@ static inline int __pmdp_test_and_clear_young(struct mm_struct *mm,
static inline void pmdp_set_wrprotect(struct mm_struct *mm, unsigned long addr,
pmd_t *pmdp)
{
- if (__pmd_write((*pmdp)))
+ if (pmd_write(*pmdp))
pmd_hugepage_update(mm, addr, pmdp, _PAGE_WRITE, 0);
- else if (unlikely(pmd_savedwrite(*pmdp)))
- pmd_hugepage_update(mm, addr, pmdp, 0, _PAGE_PRIVILEGED);
}

/*
diff --git a/arch/powerpc/kvm/book3s_hv_rm_mmu.c b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
index 5a05953ae13f..9182324dbef9 100644
--- a/arch/powerpc/kvm/book3s_hv_rm_mmu.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_mmu.c
@@ -265,7 +265,7 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
}
pte = kvmppc_read_update_linux_pte(ptep, writing);
if (pte_present(pte) && !pte_protnone(pte)) {
- if (writing && !__pte_write(pte))
+ if (writing && !pte_write(pte))
/* make the actual HPTE be read-only */
ptel = hpte_make_readonly(ptel);
is_ci = pte_ci(pte);
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index d13b4f7cc5be..02d88fdb44af 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -472,30 +472,6 @@ static inline pte_t pte_sw_mkyoung(pte_t pte)
#define pte_sw_mkyoung pte_sw_mkyoung
#endif

-#ifndef pte_savedwrite
-#define pte_savedwrite pte_write
-#endif
-
-#ifndef pte_mk_savedwrite
-#define pte_mk_savedwrite pte_mkwrite
-#endif
-
-#ifndef pte_clear_savedwrite
-#define pte_clear_savedwrite pte_wrprotect
-#endif
-
-#ifndef pmd_savedwrite
-#define pmd_savedwrite pmd_write
-#endif
-
-#ifndef pmd_mk_savedwrite
-#define pmd_mk_savedwrite pmd_mkwrite
-#endif
-
-#ifndef pmd_clear_savedwrite
-#define pmd_clear_savedwrite pmd_wrprotect
-#endif
-
#ifndef __HAVE_ARCH_PMDP_SET_WRPROTECT
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline void pmdp_set_wrprotect(struct mm_struct *mm,
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index dc7df1254f0a..5dae04c05d79 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -175,18 +175,6 @@ static void __init pte_advanced_tests(struct pgtable_debug_args *args)
ptep_get_and_clear_full(args->mm, args->vaddr, args->ptep, 1);
}

-static void __init pte_savedwrite_tests(struct pgtable_debug_args *args)
-{
- pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot_none);
-
- if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
- return;
-
- pr_debug("Validating PTE saved write\n");
- WARN_ON(!pte_savedwrite(pte_mk_savedwrite(pte_clear_savedwrite(pte))));
- WARN_ON(pte_savedwrite(pte_clear_savedwrite(pte_mk_savedwrite(pte))));
-}
-
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx)
{
@@ -306,22 +294,6 @@ static void __init pmd_leaf_tests(struct pgtable_debug_args *args)
WARN_ON(!pmd_leaf(pmd));
}

-static void __init pmd_savedwrite_tests(struct pgtable_debug_args *args)
-{
- pmd_t pmd;
-
- if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
- return;
-
- if (!has_transparent_hugepage())
- return;
-
- pr_debug("Validating PMD saved write\n");
- pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot_none);
- WARN_ON(!pmd_savedwrite(pmd_mk_savedwrite(pmd_clear_savedwrite(pmd))));
- WARN_ON(pmd_savedwrite(pmd_clear_savedwrite(pmd_mk_savedwrite(pmd))));
-}
-
#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx)
{
@@ -455,7 +427,6 @@ static void __init pmd_advanced_tests(struct pgtable_debug_args *args) { }
static void __init pud_advanced_tests(struct pgtable_debug_args *args) { }
static void __init pmd_leaf_tests(struct pgtable_debug_args *args) { }
static void __init pud_leaf_tests(struct pgtable_debug_args *args) { }
-static void __init pmd_savedwrite_tests(struct pgtable_debug_args *args) { }
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
@@ -1292,9 +1263,6 @@ static int __init debug_vm_pgtable(void)
pmd_leaf_tests(&args);
pud_leaf_tests(&args);

- pte_savedwrite_tests(&args);
- pmd_savedwrite_tests(&args);
-
pte_special_tests(&args);
pte_protnone_tests(&args);
pmd_protnone_tests(&args);
--
2.37.3
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