powerpc/mm: Switch to generic RCU get_user_pages_fast
authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Wed, 5 Nov 2014 16:27:41 +0000 (21:57 +0530)
committerMichael Ellerman <mpe@ellerman.id.au>
Fri, 14 Nov 2014 06:24:21 +0000 (17:24 +1100)
This patch switch the ppc arch to use the generic RCU based
gup implementation.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
arch/powerpc/Kconfig
arch/powerpc/include/asm/hugetlb.h
arch/powerpc/include/asm/page.h
arch/powerpc/include/asm/pgtable-ppc64.h
arch/powerpc/include/asm/pgtable.h
arch/powerpc/mm/Makefile
arch/powerpc/mm/gup.c [deleted file]
arch/powerpc/mm/hugetlbpage.c

index 98e9c54..4622733 100644 (file)
@@ -149,6 +149,7 @@ config PPC
        select ARCH_SUPPORTS_ATOMIC_RMW
        select DCACHE_WORD_ACCESS if PPC64 && CPU_LITTLE_ENDIAN
        select NO_BOOTMEM
+       select HAVE_GENERIC_RCU_GUP
 
 config GENERIC_CSUM
        def_bool CPU_LITTLE_ENDIAN
index 766b77d..1d53a65 100644 (file)
@@ -48,7 +48,7 @@ static inline unsigned int hugepd_shift(hugepd_t hpd)
 #endif /* CONFIG_PPC_BOOK3S_64 */
 
 
-static inline pte_t *hugepte_offset(hugepd_t *hpdp, unsigned long addr,
+static inline pte_t *hugepte_offset(hugepd_t hpd, unsigned long addr,
                                    unsigned pdshift)
 {
        /*
@@ -58,9 +58,9 @@ static inline pte_t *hugepte_offset(hugepd_t *hpdp, unsigned long addr,
         */
        unsigned long idx = 0;
 
-       pte_t *dir = hugepd_page(*hpdp);
+       pte_t *dir = hugepd_page(hpd);
 #ifndef CONFIG_PPC_FSL_BOOK3E
-       idx = (addr & ((1UL << pdshift) - 1)) >> hugepd_shift(*hpdp);
+       idx = (addr & ((1UL << pdshift) - 1)) >> hugepd_shift(hpd);
 #endif
 
        return dir + idx;
@@ -193,7 +193,7 @@ static inline void flush_hugetlb_page(struct vm_area_struct *vma,
 }
 
 #define hugepd_shift(x) 0
-static inline pte_t *hugepte_offset(hugepd_t *hpdp, unsigned long addr,
+static inline pte_t *hugepte_offset(hugepd_t hpd, unsigned long addr,
                                    unsigned pdshift)
 {
        return 0;
index f973fce..69c0598 100644 (file)
@@ -379,13 +379,14 @@ static inline int hugepd_ok(hugepd_t hpd)
 }
 #endif
 
-#define is_hugepd(pdep)               (hugepd_ok(*((hugepd_t *)(pdep))))
+#define is_hugepd(hpd)               (hugepd_ok(hpd))
 #define pgd_huge pgd_huge
 int pgd_huge(pgd_t pgd);
 #else /* CONFIG_HUGETLB_PAGE */
 #define is_hugepd(pdep)                        0
 #define pgd_huge(pgd)                  0
 #endif /* CONFIG_HUGETLB_PAGE */
+#define __hugepd(x) ((hugepd_t) { (x) })
 
 struct page;
 extern void clear_user_page(void *page, unsigned long vaddr, struct page *pg);
index d120924..5600e43 100644 (file)
@@ -600,6 +600,5 @@ static inline int pmd_move_must_withdraw(struct spinlock *new_pmd_ptl,
         */
        return true;
 }
-
 #endif /* __ASSEMBLY__ */
 #endif /* _ASM_POWERPC_PGTABLE_PPC64_H_ */
index 316f9a5..a8805fe 100644 (file)
@@ -274,11 +274,9 @@ extern void paging_init(void);
  */
 extern void update_mmu_cache(struct vm_area_struct *, unsigned long, pte_t *);
 
-extern int gup_hugepd(hugepd_t *hugepd, unsigned pdshift, unsigned long addr,
-                     unsigned long end, int write, struct page **pages, int *nr);
-
 extern int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
-                      unsigned long end, int write, struct page **pages, int *nr);
+                      unsigned long end, int write,
+                      struct page **pages, int *nr);
 #ifndef CONFIG_TRANSPARENT_HUGEPAGE
 #define pmd_large(pmd)         0
 #define has_transparent_hugepage() 0
index 325e861..438dcd3 100644 (file)
@@ -6,7 +6,7 @@ subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror
 
 ccflags-$(CONFIG_PPC64)        := $(NO_MINIMAL_TOC)
 
-obj-y                          := fault.o mem.o pgtable.o gup.o mmap.o \
+obj-y                          := fault.o mem.o pgtable.o mmap.o \
                                   init_$(CONFIG_WORD_SIZE).o \
                                   pgtable_$(CONFIG_WORD_SIZE).o
 obj-$(CONFIG_PPC_MMU_NOHASH)   += mmu_context_nohash.o tlb_nohash.o \
diff --git a/arch/powerpc/mm/gup.c b/arch/powerpc/mm/gup.c
deleted file mode 100644 (file)
index d874668..0000000
+++ /dev/null
@@ -1,235 +0,0 @@
-/*
- * Lockless get_user_pages_fast for powerpc
- *
- * Copyright (C) 2008 Nick Piggin
- * Copyright (C) 2008 Novell Inc.
- */
-#undef DEBUG
-
-#include <linux/sched.h>
-#include <linux/mm.h>
-#include <linux/hugetlb.h>
-#include <linux/vmstat.h>
-#include <linux/pagemap.h>
-#include <linux/rwsem.h>
-#include <asm/pgtable.h>
-
-#ifdef __HAVE_ARCH_PTE_SPECIAL
-
-/*
- * The performance critical leaf functions are made noinline otherwise gcc
- * inlines everything into a single function which results in too much
- * register pressure.
- */
-static noinline int gup_pte_range(pmd_t pmd, unsigned long addr,
-               unsigned long end, int write, struct page **pages, int *nr)
-{
-       unsigned long mask, result;
-       pte_t *ptep;
-
-       result = _PAGE_PRESENT|_PAGE_USER;
-       if (write)
-               result |= _PAGE_RW;
-       mask = result | _PAGE_SPECIAL;
-
-       ptep = pte_offset_kernel(&pmd, addr);
-       do {
-               pte_t pte = ACCESS_ONCE(*ptep);
-               struct page *page;
-               /*
-                * Similar to the PMD case, NUMA hinting must take slow path
-                */
-               if (pte_numa(pte))
-                       return 0;
-
-               if ((pte_val(pte) & mask) != result)
-                       return 0;
-               VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
-               page = pte_page(pte);
-               if (!page_cache_get_speculative(page))
-                       return 0;
-               if (unlikely(pte_val(pte) != pte_val(*ptep))) {
-                       put_page(page);
-                       return 0;
-               }
-               pages[*nr] = page;
-               (*nr)++;
-
-       } while (ptep++, addr += PAGE_SIZE, addr != end);
-
-       return 1;
-}
-
-static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
-               int write, struct page **pages, int *nr)
-{
-       unsigned long next;
-       pmd_t *pmdp;
-
-       pmdp = pmd_offset(&pud, addr);
-       do {
-               pmd_t pmd = ACCESS_ONCE(*pmdp);
-
-               next = pmd_addr_end(addr, end);
-               /*
-                * If we find a splitting transparent hugepage we
-                * return zero. That will result in taking the slow
-                * path which will call wait_split_huge_page()
-                * if the pmd is still in splitting state
-                */
-               if (pmd_none(pmd) || pmd_trans_splitting(pmd))
-                       return 0;
-               if (pmd_huge(pmd) || pmd_large(pmd)) {
-                       /*
-                        * NUMA hinting faults need to be handled in the GUP
-                        * slowpath for accounting purposes and so that they
-                        * can be serialised against THP migration.
-                        */
-                       if (pmd_numa(pmd))
-                               return 0;
-
-                       if (!gup_hugepte((pte_t *)pmdp, PMD_SIZE, addr, next,
-                                        write, pages, nr))
-                               return 0;
-               } else if (is_hugepd(pmdp)) {
-                       if (!gup_hugepd((hugepd_t *)pmdp, PMD_SHIFT,
-                                       addr, next, write, pages, nr))
-                               return 0;
-               } else if (!gup_pte_range(pmd, addr, next, write, pages, nr))
-                       return 0;
-       } while (pmdp++, addr = next, addr != end);
-
-       return 1;
-}
-
-static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,
-               int write, struct page **pages, int *nr)
-{
-       unsigned long next;
-       pud_t *pudp;
-
-       pudp = pud_offset(&pgd, addr);
-       do {
-               pud_t pud = ACCESS_ONCE(*pudp);
-
-               next = pud_addr_end(addr, end);
-               if (pud_none(pud))
-                       return 0;
-               if (pud_huge(pud)) {
-                       if (!gup_hugepte((pte_t *)pudp, PUD_SIZE, addr, next,
-                                        write, pages, nr))
-                               return 0;
-               } else if (is_hugepd(pudp)) {
-                       if (!gup_hugepd((hugepd_t *)pudp, PUD_SHIFT,
-                                       addr, next, write, pages, nr))
-                               return 0;
-               } else if (!gup_pmd_range(pud, addr, next, write, pages, nr))
-                       return 0;
-       } while (pudp++, addr = next, addr != end);
-
-       return 1;
-}
-
-int __get_user_pages_fast(unsigned long start, int nr_pages, int write,
-                         struct page **pages)
-{
-       struct mm_struct *mm = current->mm;
-       unsigned long addr, len, end;
-       unsigned long next;
-       unsigned long flags;
-       pgd_t *pgdp;
-       int nr = 0;
-
-       pr_devel("%s(%lx,%x,%s)\n", __func__, start, nr_pages, write ? "write" : "read");
-
-       start &= PAGE_MASK;
-       addr = start;
-       len = (unsigned long) nr_pages << PAGE_SHIFT;
-       end = start + len;
-
-       if (unlikely(!access_ok(write ? VERIFY_WRITE : VERIFY_READ,
-                                       start, len)))
-               return 0;
-
-       pr_devel("  aligned: %lx .. %lx\n", start, end);
-
-       /*
-        * XXX: batch / limit 'nr', to avoid large irq off latency
-        * needs some instrumenting to determine the common sizes used by
-        * important workloads (eg. DB2), and whether limiting the batch size
-        * will decrease performance.
-        *
-        * It seems like we're in the clear for the moment. Direct-IO is
-        * the main guy that batches up lots of get_user_pages, and even
-        * they are limited to 64-at-a-time which is not so many.
-        */
-       /*
-        * This doesn't prevent pagetable teardown, but does prevent
-        * the pagetables from being freed on powerpc.
-        *
-        * So long as we atomically load page table pointers versus teardown,
-        * we can follow the address down to the the page and take a ref on it.
-        */
-       local_irq_save(flags);
-
-       pgdp = pgd_offset(mm, addr);
-       do {
-               pgd_t pgd = ACCESS_ONCE(*pgdp);
-
-               pr_devel("  %016lx: normal pgd %p\n", addr,
-                        (void *)pgd_val(pgd));
-               next = pgd_addr_end(addr, end);
-               if (pgd_none(pgd))
-                       break;
-               if (pgd_huge(pgd)) {
-                       if (!gup_hugepte((pte_t *)pgdp, PGDIR_SIZE, addr, next,
-                                        write, pages, &nr))
-                               break;
-               } else if (is_hugepd(pgdp)) {
-                       if (!gup_hugepd((hugepd_t *)pgdp, PGDIR_SHIFT,
-                                       addr, next, write, pages, &nr))
-                               break;
-               } else if (!gup_pud_range(pgd, addr, next, write, pages, &nr))
-                       break;
-       } while (pgdp++, addr = next, addr != end);
-
-       local_irq_restore(flags);
-
-       return nr;
-}
-
-int get_user_pages_fast(unsigned long start, int nr_pages, int write,
-                       struct page **pages)
-{
-       struct mm_struct *mm = current->mm;
-       int nr, ret;
-
-       start &= PAGE_MASK;
-       nr = __get_user_pages_fast(start, nr_pages, write, pages);
-       ret = nr;
-
-       if (nr < nr_pages) {
-               pr_devel("  slow path ! nr = %d\n", nr);
-
-               /* Try to get the remaining pages with get_user_pages */
-               start += nr << PAGE_SHIFT;
-               pages += nr;
-
-               down_read(&mm->mmap_sem);
-               ret = get_user_pages(current, mm, start,
-                                    nr_pages - nr, write, 0, pages, NULL);
-               up_read(&mm->mmap_sem);
-
-               /* Have to be a bit careful with return values */
-               if (nr > 0) {
-                       if (ret < 0)
-                               ret = nr;
-                       else
-                               ret += nr;
-               }
-       }
-
-       return ret;
-}
-
-#endif /* __HAVE_ARCH_PTE_SPECIAL */
index 2b8e5ed..af56de8 100644 (file)
@@ -233,7 +233,7 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz
        if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift))
                return NULL;
 
-       return hugepte_offset(hpdp, addr, pdshift);
+       return hugepte_offset(*hpdp, addr, pdshift);
 }
 
 #else
@@ -273,7 +273,7 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz
        if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift))
                return NULL;
 
-       return hugepte_offset(hpdp, addr, pdshift);
+       return hugepte_offset(*hpdp, addr, pdshift);
 }
 #endif
 
@@ -541,7 +541,7 @@ static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
        do {
                pmd = pmd_offset(pud, addr);
                next = pmd_addr_end(addr, end);
-               if (!is_hugepd(pmd)) {
+               if (!is_hugepd(__hugepd(pmd_val(*pmd)))) {
                        /*
                         * if it is not hugepd pointer, we should already find
                         * it cleared.
@@ -590,7 +590,7 @@ static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
        do {
                pud = pud_offset(pgd, addr);
                next = pud_addr_end(addr, end);
-               if (!is_hugepd(pud)) {
+               if (!is_hugepd(__hugepd(pud_val(*pud)))) {
                        if (pud_none_or_clear_bad(pud))
                                continue;
                        hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
@@ -656,7 +656,7 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
        do {
                next = pgd_addr_end(addr, end);
                pgd = pgd_offset(tlb->mm, addr);
-               if (!is_hugepd(pgd)) {
+               if (!is_hugepd(__hugepd(pgd_val(*pgd)))) {
                        if (pgd_none_or_clear_bad(pgd))
                                continue;
                        hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
@@ -716,12 +716,11 @@ static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
        return (__boundary - 1 < end - 1) ? __boundary : end;
 }
 
-int gup_hugepd(hugepd_t *hugepd, unsigned pdshift,
-              unsigned long addr, unsigned long end,
-              int write, struct page **pages, int *nr)
+int gup_huge_pd(hugepd_t hugepd, unsigned long addr, unsigned pdshift,
+               unsigned long end, int write, struct page **pages, int *nr)
 {
        pte_t *ptep;
-       unsigned long sz = 1UL << hugepd_shift(*hugepd);
+       unsigned long sz = 1UL << hugepd_shift(hugepd);
        unsigned long next;
 
        ptep = hugepte_offset(hugepd, addr, pdshift);
@@ -964,7 +963,7 @@ pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift
        else if (pgd_huge(pgd)) {
                ret_pte = (pte_t *) pgdp;
                goto out;
-       } else if (is_hugepd(&pgd))
+       } else if (is_hugepd(__hugepd(pgd_val(pgd))))
                hpdp = (hugepd_t *)&pgd;
        else {
                /*
@@ -981,7 +980,7 @@ pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift
                else if (pud_huge(pud)) {
                        ret_pte = (pte_t *) pudp;
                        goto out;
-               } else if (is_hugepd(&pud))
+               } else if (is_hugepd(__hugepd(pud_val(pud))))
                        hpdp = (hugepd_t *)&pud;
                else {
                        pdshift = PMD_SHIFT;
@@ -1002,7 +1001,7 @@ pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift
                        if (pmd_huge(pmd) || pmd_large(pmd)) {
                                ret_pte = (pte_t *) pmdp;
                                goto out;
-                       } else if (is_hugepd(&pmd))
+                       } else if (is_hugepd(__hugepd(pmd_val(pmd))))
                                hpdp = (hugepd_t *)&pmd;
                        else
                                return pte_offset_kernel(&pmd, ea);
@@ -1011,7 +1010,7 @@ pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift
        if (!hpdp)
                return NULL;
 
-       ret_pte = hugepte_offset(hpdp, ea, pdshift);
+       ret_pte = hugepte_offset(*hpdp, ea, pdshift);
        pdshift = hugepd_shift(*hpdp);
 out:
        if (shift)
@@ -1041,14 +1040,6 @@ int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
        if ((pte_val(pte) & mask) != mask)
                return 0;
 
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-       /*
-        * check for splitting here
-        */
-       if (pmd_trans_splitting(pte_pmd(pte)))
-               return 0;
-#endif
-
        /* hugepages are never "special" */
        VM_BUG_ON(!pfn_valid(pte_pfn(pte)));