X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=mm%2Fswapfile.c;h=2f33edb8bee9d5409880be93364cc1d4be4c3735;hb=18b095d4b847bb08bf8a1bace7711a93d27732c0;hp=afae7b1f680b5f4140d305d2a5be7fb476f50fd5;hpb=59bd26582de660d4c9c26125747f1b4a5eb40d1e;p=linux-2.6 diff --git a/mm/swapfile.c b/mm/swapfile.c index afae7b1f68..2f33edb8be 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -27,6 +27,7 @@ #include #include #include +#include #include #include @@ -36,6 +37,7 @@ DEFINE_SPINLOCK(swap_lock); unsigned int nr_swapfiles; long total_swap_pages; static int swap_overflow; +static int least_priority; static const char Bad_file[] = "Bad swap file entry "; static const char Unused_file[] = "Unused swap file entry "; @@ -506,9 +508,24 @@ unsigned int count_swap_pages(int type, int free) * just let do_wp_page work it out if a write is requested later - to * force COW, vm_page_prot omits write permission from any private vma. */ -static void unuse_pte(struct vm_area_struct *vma, pte_t *pte, +static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, unsigned long addr, swp_entry_t entry, struct page *page) { + spinlock_t *ptl; + pte_t *pte; + int ret = 1; + + if (mem_cgroup_charge(page, vma->vm_mm, GFP_KERNEL)) + ret = -ENOMEM; + + pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + if (unlikely(!pte_same(*pte, swp_entry_to_pte(entry)))) { + if (ret > 0) + mem_cgroup_uncharge_page(page); + ret = 0; + goto out; + } + inc_mm_counter(vma->vm_mm, anon_rss); get_page(page); set_pte_at(vma->vm_mm, addr, pte, @@ -520,6 +537,9 @@ static void unuse_pte(struct vm_area_struct *vma, pte_t *pte, * immediately swapped out again after swapon. */ activate_page(page); +out: + pte_unmap_unlock(pte, ptl); + return ret; } static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, @@ -528,23 +548,34 @@ static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd, { pte_t swp_pte = swp_entry_to_pte(entry); pte_t *pte; - spinlock_t *ptl; - int found = 0; + int ret = 0; - pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + /* + * We don't actually need pte lock while scanning for swp_pte: since + * we hold page lock and mmap_sem, swp_pte cannot be inserted into the + * page table while we're scanning; though it could get zapped, and on + * some architectures (e.g. x86_32 with PAE) we might catch a glimpse + * of unmatched parts which look like swp_pte, so unuse_pte must + * recheck under pte lock. Scanning without pte lock lets it be + * preemptible whenever CONFIG_PREEMPT but not CONFIG_HIGHPTE. + */ + pte = pte_offset_map(pmd, addr); do { /* * swapoff spends a _lot_ of time in this loop! * Test inline before going to call unuse_pte. */ if (unlikely(pte_same(*pte, swp_pte))) { - unuse_pte(vma, pte++, addr, entry, page); - found = 1; - break; + pte_unmap(pte); + ret = unuse_pte(vma, pmd, addr, entry, page); + if (ret) + goto out; + pte = pte_offset_map(pmd, addr); } } while (pte++, addr += PAGE_SIZE, addr != end); - pte_unmap_unlock(pte - 1, ptl); - return found; + pte_unmap(pte - 1); +out: + return ret; } static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, @@ -553,14 +584,16 @@ static inline int unuse_pmd_range(struct vm_area_struct *vma, pud_t *pud, { pmd_t *pmd; unsigned long next; + int ret; pmd = pmd_offset(pud, addr); do { next = pmd_addr_end(addr, end); if (pmd_none_or_clear_bad(pmd)) continue; - if (unuse_pte_range(vma, pmd, addr, next, entry, page)) - return 1; + ret = unuse_pte_range(vma, pmd, addr, next, entry, page); + if (ret) + return ret; } while (pmd++, addr = next, addr != end); return 0; } @@ -571,14 +604,16 @@ static inline int unuse_pud_range(struct vm_area_struct *vma, pgd_t *pgd, { pud_t *pud; unsigned long next; + int ret; pud = pud_offset(pgd, addr); do { next = pud_addr_end(addr, end); if (pud_none_or_clear_bad(pud)) continue; - if (unuse_pmd_range(vma, pud, addr, next, entry, page)) - return 1; + ret = unuse_pmd_range(vma, pud, addr, next, entry, page); + if (ret) + return ret; } while (pud++, addr = next, addr != end); return 0; } @@ -588,6 +623,7 @@ static int unuse_vma(struct vm_area_struct *vma, { pgd_t *pgd; unsigned long addr, end, next; + int ret; if (page->mapping) { addr = page_address_in_vma(page, vma); @@ -605,8 +641,9 @@ static int unuse_vma(struct vm_area_struct *vma, next = pgd_addr_end(addr, end); if (pgd_none_or_clear_bad(pgd)) continue; - if (unuse_pud_range(vma, pgd, addr, next, entry, page)) - return 1; + ret = unuse_pud_range(vma, pgd, addr, next, entry, page); + if (ret) + return ret; } while (pgd++, addr = next, addr != end); return 0; } @@ -615,6 +652,7 @@ static int unuse_mm(struct mm_struct *mm, swp_entry_t entry, struct page *page) { struct vm_area_struct *vma; + int ret = 0; if (!down_read_trylock(&mm->mmap_sem)) { /* @@ -627,15 +665,11 @@ static int unuse_mm(struct mm_struct *mm, lock_page(page); } for (vma = mm->mmap; vma; vma = vma->vm_next) { - if (vma->anon_vma && unuse_vma(vma, entry, page)) + if (vma->anon_vma && (ret = unuse_vma(vma, entry, page))) break; } up_read(&mm->mmap_sem); - /* - * Currently unuse_mm cannot fail, but leave error handling - * at call sites for now, since we change it from time to time. - */ - return 0; + return (ret < 0)? ret: 0; } /* @@ -1227,6 +1261,11 @@ asmlinkage long sys_swapoff(const char __user * specialfile) /* just pick something that's safe... */ swap_list.next = swap_list.head; } + if (p->prio < 0) { + for (i = p->next; i >= 0; i = swap_info[i].next) + swap_info[i].prio = p->prio--; + least_priority++; + } nr_swap_pages -= p->pages; total_swap_pages -= p->pages; p->flags &= ~SWP_WRITEOK; @@ -1239,9 +1278,14 @@ asmlinkage long sys_swapoff(const char __user * specialfile) if (err) { /* re-insert swap space back into swap_list */ spin_lock(&swap_lock); - for (prev = -1, i = swap_list.head; i >= 0; prev = i, i = swap_info[i].next) + if (p->prio < 0) + p->prio = --least_priority; + prev = -1; + for (i = swap_list.head; i >= 0; i = swap_info[i].next) { if (p->prio >= swap_info[i].prio) break; + prev = i; + } p->next = i; if (prev < 0) swap_list.head = swap_list.next = p - swap_info; @@ -1361,7 +1405,7 @@ static int swap_show(struct seq_file *swap, void *v) } file = ptr->swap_file; - len = seq_path(swap, file->f_path.mnt, file->f_path.dentry, " \t\n\\"); + len = seq_path(swap, &file->f_path, " \t\n\\"); seq_printf(swap, "%*s%s\t%u\t%u\t%d\n", len < 40 ? 40 - len : 1, " ", S_ISBLK(file->f_path.dentry->d_inode->i_mode) ? @@ -1393,11 +1437,7 @@ static const struct file_operations proc_swaps_operations = { static int __init procswaps_init(void) { - struct proc_dir_entry *entry; - - entry = create_proc_entry("swaps", 0, NULL); - if (entry) - entry->proc_fops = &proc_swaps_operations; + proc_create("swaps", 0, NULL, &proc_swaps_operations); return 0; } __initcall(procswaps_init); @@ -1418,7 +1458,6 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) unsigned int type; int i, prev; int error; - static int least_priority; union swap_header *swap_header = NULL; int swap_header_version; unsigned int nr_good_pages = 0; @@ -1426,7 +1465,7 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) sector_t span; unsigned long maxpages = 1; int swapfilesize; - unsigned short *swap_map; + unsigned short *swap_map = NULL; struct page *page = NULL; struct inode *inode = NULL; int did_down = 0; @@ -1445,22 +1484,10 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) } if (type >= nr_swapfiles) nr_swapfiles = type+1; + memset(p, 0, sizeof(*p)); INIT_LIST_HEAD(&p->extent_list); p->flags = SWP_USED; - p->swap_file = NULL; - p->old_block_size = 0; - p->swap_map = NULL; - p->lowest_bit = 0; - p->highest_bit = 0; - p->cluster_nr = 0; - p->inuse_pages = 0; p->next = -1; - if (swap_flags & SWAP_FLAG_PREFER) { - p->prio = - (swap_flags & SWAP_FLAG_PRIO_MASK)>>SWAP_FLAG_PRIO_SHIFT; - } else { - p->prio = --least_priority; - } spin_unlock(&swap_lock); name = getname(specialfile); error = PTR_ERR(name); @@ -1549,6 +1576,14 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) error = -EINVAL; goto bad_swap; case 2: + /* swap partition endianess hack... */ + if (swab32(swap_header->info.version) == 1) { + swab32s(&swap_header->info.version); + swab32s(&swap_header->info.last_page); + swab32s(&swap_header->info.nr_badpages); + for (i = 0; i < swap_header->info.nr_badpages; i++) + swab32s(&swap_header->info.badpages[i]); + } /* Check the swap header's sub-version and the size of the swap file and bad block lists */ if (swap_header->info.version != 1) { @@ -1595,19 +1630,20 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) goto bad_swap; /* OK, set up the swap map and apply the bad block list */ - if (!(p->swap_map = vmalloc(maxpages * sizeof(short)))) { + swap_map = vmalloc(maxpages * sizeof(short)); + if (!swap_map) { error = -ENOMEM; goto bad_swap; } error = 0; - memset(p->swap_map, 0, maxpages * sizeof(short)); + memset(swap_map, 0, maxpages * sizeof(short)); for (i = 0; i < swap_header->info.nr_badpages; i++) { int page_nr = swap_header->info.badpages[i]; if (page_nr <= 0 || page_nr >= swap_header->info.last_page) error = -EINVAL; else - p->swap_map[page_nr] = SWAP_MAP_BAD; + swap_map[page_nr] = SWAP_MAP_BAD; } nr_good_pages = swap_header->info.last_page - swap_header->info.nr_badpages - @@ -1617,7 +1653,7 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) } if (nr_good_pages) { - p->swap_map[0] = SWAP_MAP_BAD; + swap_map[0] = SWAP_MAP_BAD; p->max = maxpages; p->pages = nr_good_pages; nr_extents = setup_swap_extents(p, &span); @@ -1635,6 +1671,12 @@ asmlinkage long sys_swapon(const char __user * specialfile, int swap_flags) mutex_lock(&swapon_mutex); spin_lock(&swap_lock); + if (swap_flags & SWAP_FLAG_PREFER) + p->prio = + (swap_flags & SWAP_FLAG_PRIO_MASK) >> SWAP_FLAG_PRIO_SHIFT; + else + p->prio = --least_priority; + p->swap_map = swap_map; p->flags = SWP_ACTIVE; nr_swap_pages += nr_good_pages; total_swap_pages += nr_good_pages; @@ -1670,12 +1712,8 @@ bad_swap: destroy_swap_extents(p); bad_swap_2: spin_lock(&swap_lock); - swap_map = p->swap_map; p->swap_file = NULL; - p->swap_map = NULL; p->flags = 0; - if (!(swap_flags & SWAP_FLAG_PREFER)) - ++least_priority; spin_unlock(&swap_lock); vfree(swap_map); if (swap_file)