]> err.no Git - linux-2.6/blobdiff - mm/memory.c
[PATCH] mm: more rmap debugging
[linux-2.6] / mm / memory.c
index 601159a46ab64e538dc1c2cbe710776e3ecb5208..563792f4f687e6e6dde9f98aaf87d3116b82daff 100644 (file)
@@ -467,7 +467,7 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
         */
        if (is_cow_mapping(vm_flags)) {
                ptep_set_wrprotect(src_mm, addr, src_pte);
-               pte = *src_pte;
+               pte = pte_wrprotect(pte);
        }
 
        /*
@@ -506,6 +506,7 @@ again:
        src_pte = pte_offset_map_nested(src_pmd, addr);
        src_ptl = pte_lockptr(src_mm, src_pmd);
        spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING);
+       arch_enter_lazy_mmu_mode();
 
        do {
                /*
@@ -527,6 +528,7 @@ again:
                progress += 8;
        } while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
 
+       arch_leave_lazy_mmu_mode();
        spin_unlock(src_ptl);
        pte_unmap_nested(src_pte - 1);
        add_mm_rss(dst_mm, rss[0], rss[1]);
@@ -628,6 +630,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
        int anon_rss = 0;
 
        pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
+       arch_enter_lazy_mmu_mode();
        do {
                pte_t ptent = *pte;
                if (pte_none(ptent)) {
@@ -678,7 +681,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
                                        mark_page_accessed(page);
                                file_rss--;
                        }
-                       page_remove_rmap(page);
+                       page_remove_rmap(page, vma);
                        tlb_remove_page(tlb, page);
                        continue;
                }
@@ -690,10 +693,11 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
                        continue;
                if (!pte_file(ptent))
                        free_swap_and_cache(pte_to_swp_entry(ptent));
-               pte_clear_full(mm, addr, pte, tlb->fullmm);
+               pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
        } while (pte++, addr += PAGE_SIZE, (addr != end && *zap_work > 0));
 
        add_mm_rss(mm, file_rss, anon_rss);
+       arch_leave_lazy_mmu_mode();
        pte_unmap_unlock(pte - 1, ptl);
 
        return addr;
@@ -1082,6 +1086,7 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                                default:
                                        BUG();
                                }
+                               cond_resched();
                        }
                        if (pages) {
                                pages[i] = page;
@@ -1105,21 +1110,29 @@ static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
 {
        pte_t *pte;
        spinlock_t *ptl;
+       int err = 0;
 
        pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
        if (!pte)
-               return -ENOMEM;
+               return -EAGAIN;
+       arch_enter_lazy_mmu_mode();
        do {
                struct page *page = ZERO_PAGE(addr);
                pte_t zero_pte = pte_wrprotect(mk_pte(page, prot));
+
+               if (unlikely(!pte_none(*pte))) {
+                       err = -EEXIST;
+                       pte++;
+                       break;
+               }
                page_cache_get(page);
                page_add_file_rmap(page);
                inc_mm_counter(mm, file_rss);
-               BUG_ON(!pte_none(*pte));
                set_pte_at(mm, addr, pte, zero_pte);
        } while (pte++, addr += PAGE_SIZE, addr != end);
+       arch_leave_lazy_mmu_mode();
        pte_unmap_unlock(pte - 1, ptl);
-       return 0;
+       return err;
 }
 
 static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
@@ -1127,16 +1140,18 @@ static inline int zeromap_pmd_range(struct mm_struct *mm, pud_t *pud,
 {
        pmd_t *pmd;
        unsigned long next;
+       int err;
 
        pmd = pmd_alloc(mm, pud, addr);
        if (!pmd)
-               return -ENOMEM;
+               return -EAGAIN;
        do {
                next = pmd_addr_end(addr, end);
-               if (zeromap_pte_range(mm, pmd, addr, next, prot))
-                       return -ENOMEM;
+               err = zeromap_pte_range(mm, pmd, addr, next, prot);
+               if (err)
+                       break;
        } while (pmd++, addr = next, addr != end);
-       return 0;
+       return err;
 }
 
 static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
@@ -1144,16 +1159,18 @@ static inline int zeromap_pud_range(struct mm_struct *mm, pgd_t *pgd,
 {
        pud_t *pud;
        unsigned long next;
+       int err;
 
        pud = pud_alloc(mm, pgd, addr);
        if (!pud)
-               return -ENOMEM;
+               return -EAGAIN;
        do {
                next = pud_addr_end(addr, end);
-               if (zeromap_pmd_range(mm, pud, addr, next, prot))
-                       return -ENOMEM;
+               err = zeromap_pmd_range(mm, pud, addr, next, prot);
+               if (err)
+                       break;
        } while (pud++, addr = next, addr != end);
-       return 0;
+       return err;
 }
 
 int zeromap_page_range(struct vm_area_struct *vma,
@@ -1275,11 +1292,13 @@ static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
        pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
        if (!pte)
                return -ENOMEM;
+       arch_enter_lazy_mmu_mode();
        do {
                BUG_ON(!pte_none(*pte));
                set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
                pfn++;
        } while (pte++, addr += PAGE_SIZE, addr != end);
+       arch_leave_lazy_mmu_mode();
        pte_unmap_unlock(pte - 1, ptl);
        return 0;
 }
@@ -1422,7 +1441,7 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
        return pte;
 }
 
-static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va)
+static inline void cow_user_page(struct page *dst, struct page *src, unsigned long va, struct vm_area_struct *vma)
 {
        /*
         * If the source page was a PFN mapping, we don't have
@@ -1443,10 +1462,11 @@ static inline void cow_user_page(struct page *dst, struct page *src, unsigned lo
                if (__copy_from_user_inatomic(kaddr, uaddr, PAGE_SIZE))
                        memset(kaddr, 0, PAGE_SIZE);
                kunmap_atomic(kaddr, KM_USER0);
+               flush_dcache_page(dst);
                return;
-               
+
        }
-       copy_user_highpage(dst, src, va);
+       copy_user_highpage(dst, src, va, vma);
 }
 
 /*
@@ -1557,7 +1577,7 @@ gotten:
                new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
                if (!new_page)
                        goto oom;
-               cow_user_page(new_page, old_page, address);
+               cow_user_page(new_page, old_page, address, vma);
        }
 
        /*
@@ -1566,7 +1586,7 @@ gotten:
        page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
        if (likely(pte_same(*page_table, orig_pte))) {
                if (old_page) {
-                       page_remove_rmap(old_page);
+                       page_remove_rmap(old_page, vma);
                        if (!PageAnon(old_page)) {
                                dec_mm_counter(mm, file_rss);
                                inc_mm_counter(mm, anon_rss);
@@ -1577,7 +1597,14 @@ gotten:
                entry = mk_pte(new_page, vma->vm_page_prot);
                entry = maybe_mkwrite(pte_mkdirty(entry), vma);
                lazy_mmu_prot_update(entry);
-               ptep_establish(vma, address, page_table, entry);
+               /*
+                * Clear the pte entry and flush it first, before updating the
+                * pte with the new entry. This will avoid a race condition
+                * seen in the presence of one thread doing SMC and another
+                * thread doing COW.
+                */
+               ptep_clear_flush(vma, address, page_table);
+               set_pte_at(mm, address, page_table, entry);
                update_mmu_cache(vma, address, entry);
                lru_cache_add_active(new_page);
                page_add_new_anon_rmap(new_page, vma, address);
@@ -1885,7 +1912,6 @@ int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
 
        return 0;
 }
-EXPORT_UNUSED_SYMBOL(vmtruncate_range);  /*  June 2006  */
 
 /**
  * swapin_readahead - swap in pages in hope we need them soon
@@ -1974,6 +2000,7 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
        delayacct_set_flag(DELAYACCT_PF_SWAPIN);
        page = lookup_swap_cache(entry);
        if (!page) {
+               grab_swap_token(); /* Contend for token _before_ read-in */
                swapin_readahead(entry, address, vma);
                page = read_swap_cache_async(entry, vma, address);
                if (!page) {
@@ -1991,7 +2018,6 @@ static int do_swap_page(struct mm_struct *mm, struct vm_area_struct *vma,
                /* Had to read the page from swap area: Major fault */
                ret = VM_FAULT_MAJOR;
                count_vm_event(PGMAJFAULT);
-               grab_swap_token();
        }
 
        delayacct_clear_flag(DELAYACCT_PF_SWAPIN);
@@ -2154,11 +2180,13 @@ retry:
         * after the next truncate_count read.
         */
 
-       /* no page was available -- either SIGBUS or OOM */
-       if (new_page == NOPAGE_SIGBUS)
+       /* no page was available -- either SIGBUS, OOM or REFAULT */
+       if (unlikely(new_page == NOPAGE_SIGBUS))
                return VM_FAULT_SIGBUS;
-       if (new_page == NOPAGE_OOM)
+       else if (unlikely(new_page == NOPAGE_OOM))
                return VM_FAULT_OOM;
+       else if (unlikely(new_page == NOPAGE_REFAULT))
+               return VM_FAULT_MINOR;
 
        /*
         * Should we do an early C-O-W break?
@@ -2172,7 +2200,7 @@ retry:
                        page = alloc_page_vma(GFP_HIGHUSER, vma, address);
                        if (!page)
                                goto oom;
-                       copy_user_highpage(page, new_page, address);
+                       copy_user_highpage(page, new_page, address, vma);
                        page_cache_release(new_page);
                        new_page = page;
                        anon = 1;