Messages in this thread Patch in this message | | | Date | Fri, 15 Oct 2004 12:06:52 -0700 (PDT) | From | Christoph Lameter <> | Subject | page fault scalability patch V10: [5/7] i386 atomic pte operations |
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Changelog * Atomic pte operations for i386
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Index: linux-2.6.9-rc4/include/asm-i386/pgtable.h =================================================================== --- linux-2.6.9-rc4.orig/include/asm-i386/pgtable.h 2004-10-10 19:58:24.000000000 -0700 +++ linux-2.6.9-rc4/include/asm-i386/pgtable.h 2004-10-14 11:32:37.000000000 -0700 @@ -412,6 +412,7 @@ #define __HAVE_ARCH_PTEP_SET_WRPROTECT #define __HAVE_ARCH_PTEP_MKDIRTY #define __HAVE_ARCH_PTE_SAME +#define __HAVE_ARCH_ATOMIC_TABLE_OPS #include <asm-generic/pgtable.h>
#endif /* _I386_PGTABLE_H */ Index: linux-2.6.9-rc4/include/asm-i386/pgtable-3level.h =================================================================== --- linux-2.6.9-rc4.orig/include/asm-i386/pgtable-3level.h 2004-10-10 19:58:41.000000000 -0700 +++ linux-2.6.9-rc4/include/asm-i386/pgtable-3level.h 2004-10-14 11:32:37.000000000 -0700 @@ -6,7 +6,8 @@ * tables on PPro+ CPUs. * * Copyright (C) 1999 Ingo Molnar <mingo@redhat.com> - */ + * August 26, 2004 added ptep_cmpxchg and ptep_xchg <christoph@lameter.com> +*/
#define pte_ERROR(e) \ printk("%s:%d: bad pte %p(%08lx%08lx).\n", __FILE__, __LINE__, &(e), (e).pte_high, (e).pte_low) @@ -141,4 +142,26 @@ #define __pte_to_swp_entry(pte) ((swp_entry_t){ (pte).pte_high }) #define __swp_entry_to_pte(x) ((pte_t){ 0, (x).val })
+/* Atomic PTE operations */ +static inline pte_t ptep_xchg(struct mm_struct *mm, pte_t *ptep, pte_t newval) +{ + pte_t res; + + /* xchg acts as a barrier before the setting of the high bits. + * (But we also have a cmpxchg8b. Why not use that? (cl)) + */ + res.pte_low = xchg(&ptep->pte_low, newval.pte_low); + res.pte_high = ptep->pte_high; + ptep->pte_high = newval.pte_high; + + return res; +} + + +static inline int ptep_cmpxchg(struct mm_struct *mm, unsigned long address, pte_t *ptep, pte_t oldval, pte_t newval) +{ + return cmpxchg(ptep, pte_val(oldval), pte_val(newval)) == pte_val(oldval); +} + + #endif /* _I386_PGTABLE_3LEVEL_H */ Index: linux-2.6.9-rc4/include/asm-i386/pgtable-2level.h =================================================================== --- linux-2.6.9-rc4.orig/include/asm-i386/pgtable-2level.h 2004-10-10 19:58:05.000000000 -0700 +++ linux-2.6.9-rc4/include/asm-i386/pgtable-2level.h 2004-10-14 11:32:37.000000000 -0700 @@ -82,4 +82,8 @@ #define __pte_to_swp_entry(pte) ((swp_entry_t) { (pte).pte_low }) #define __swp_entry_to_pte(x) ((pte_t) { (x).val })
+/* Atomic PTE operations */ +#define ptep_xchg(mm,xp,a) __pte(xchg(&(xp)->pte_low, (a).pte_low)) +#define ptep_cmpxchg(mm,a,xp,oldpte,newpte) (cmpxchg(&(xp)->pte_low, (oldpte).pte_low, (newpte).pte_low)==(oldpte).pte_low) + #endif /* _I386_PGTABLE_2LEVEL_H */ Index: linux-2.6.9-rc4/include/asm-i386/pgalloc.h =================================================================== --- linux-2.6.9-rc4.orig/include/asm-i386/pgalloc.h 2004-10-10 19:57:02.000000000 -0700 +++ linux-2.6.9-rc4/include/asm-i386/pgalloc.h 2004-10-14 11:32:37.000000000 -0700 @@ -7,6 +7,8 @@ #include <linux/threads.h> #include <linux/mm.h> /* for struct page */
+#define PMD_NONE 0L + #define pmd_populate_kernel(mm, pmd, pte) \ set_pmd(pmd, __pmd(_PAGE_TABLE + __pa(pte)))
@@ -16,6 +18,19 @@ ((unsigned long long)page_to_pfn(pte) << (unsigned long long) PAGE_SHIFT))); } + +/* Atomic version */ +static inline int pmd_test_and_populate(struct mm_struct *mm, pmd_t *pmd, struct page *pte) +{ +#ifdef CONFIG_X86_PAE + return cmpxchg8b( ((unsigned long long *)pmd), PMD_NONE, _PAGE_TABLE + + ((unsigned long long)page_to_pfn(pte) << + (unsigned long long) PAGE_SHIFT) ) == PMD_NONE; +#else + return cmpxchg( (unsigned long *)pmd, PMD_NONE, _PAGE_TABLE + (page_to_pfn(pte) << PAGE_SHIFT)) == PMD_NONE; +#endif +} + /* * Allocate and free page tables. */ @@ -49,6 +64,7 @@ #define pmd_free(x) do { } while (0) #define __pmd_free_tlb(tlb,x) do { } while (0) #define pgd_populate(mm, pmd, pte) BUG() +#define pgd_test_and_populate(mm, pmd, pte) ({ BUG(); 1; })
#define check_pgt_cache() do { } while (0)
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