X-Git-Url: http://git.rot13.org/?a=blobdiff_plain;ds=sidebyside;f=mm%2Fhugetlb.c;h=832f676ca038837ab87c7544d4c3344b45cdc264;hb=160882722cb21cbe5cead55cf38a5e70fc3af63e;hp=508707704d2cb714968a779e128084d640afc439;hpb=1f84253e3ce75fc1b2946a544e16c5c0c13c7017;p=powerpc.git diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 508707704d..832f676ca0 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -13,24 +13,48 @@ #include #include #include +#include #include #include #include +#include "internal.h" const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; -static unsigned long nr_huge_pages, free_huge_pages; +static unsigned long nr_huge_pages, free_huge_pages, reserved_huge_pages; unsigned long max_huge_pages; static struct list_head hugepage_freelists[MAX_NUMNODES]; static unsigned int nr_huge_pages_node[MAX_NUMNODES]; static unsigned int free_huge_pages_node[MAX_NUMNODES]; - /* * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages */ static DEFINE_SPINLOCK(hugetlb_lock); +static void clear_huge_page(struct page *page, unsigned long addr) +{ + int i; + + might_sleep(); + for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); i++) { + cond_resched(); + clear_user_highpage(page + i, addr); + } +} + +static void copy_huge_page(struct page *dst, struct page *src, + unsigned long addr) +{ + int i; + + might_sleep(); + for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++) { + cond_resched(); + copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE); + } +} + static void enqueue_huge_page(struct page *page) { int nid = page_to_nid(page); @@ -64,57 +88,176 @@ static struct page *dequeue_huge_page(struct vm_area_struct *vma, return page; } -static struct page *alloc_fresh_huge_page(void) +static void free_huge_page(struct page *page) +{ + BUG_ON(page_count(page)); + + INIT_LIST_HEAD(&page->lru); + + spin_lock(&hugetlb_lock); + enqueue_huge_page(page); + spin_unlock(&hugetlb_lock); +} + +static int alloc_fresh_huge_page(void) { static int nid = 0; struct page *page; page = alloc_pages_node(nid, GFP_HIGHUSER|__GFP_COMP|__GFP_NOWARN, HUGETLB_PAGE_ORDER); - nid = (nid + 1) % num_online_nodes(); + nid = next_node(nid, node_online_map); + if (nid == MAX_NUMNODES) + nid = first_node(node_online_map); if (page) { + page[1].lru.next = (void *)free_huge_page; /* dtor */ spin_lock(&hugetlb_lock); nr_huge_pages++; nr_huge_pages_node[page_to_nid(page)]++; spin_unlock(&hugetlb_lock); + put_page(page); /* free it into the hugepage allocator */ + return 1; } - return page; + return 0; } -void free_huge_page(struct page *page) +static struct page *alloc_huge_page(struct vm_area_struct *vma, + unsigned long addr) { - BUG_ON(page_count(page)); + struct inode *inode = vma->vm_file->f_dentry->d_inode; + struct page *page; + int use_reserve = 0; + unsigned long idx; - INIT_LIST_HEAD(&page->lru); - page[1].lru.next = NULL; /* reset dtor */ + spin_lock(&hugetlb_lock); + + if (vma->vm_flags & VM_MAYSHARE) { + + /* idx = radix tree index, i.e. offset into file in + * HPAGE_SIZE units */ + idx = ((addr - vma->vm_start) >> HPAGE_SHIFT) + + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT)); + + /* The hugetlbfs specific inode info stores the number + * of "guaranteed available" (huge) pages. That is, + * the first 'prereserved_hpages' pages of the inode + * are either already instantiated, or have been + * pre-reserved (by hugetlb_reserve_for_inode()). Here + * we're in the process of instantiating the page, so + * we use this to determine whether to draw from the + * pre-reserved pool or the truly free pool. */ + if (idx < HUGETLBFS_I(inode)->prereserved_hpages) + use_reserve = 1; + } + + if (!use_reserve) { + if (free_huge_pages <= reserved_huge_pages) + goto fail; + } else { + BUG_ON(reserved_huge_pages == 0); + reserved_huge_pages--; + } + + page = dequeue_huge_page(vma, addr); + if (!page) + goto fail; + + spin_unlock(&hugetlb_lock); + set_page_refcounted(page); + return page; + + fail: + WARN_ON(use_reserve); /* reserved allocations shouldn't fail */ + spin_unlock(&hugetlb_lock); + return NULL; +} + +/* hugetlb_extend_reservation() + * + * Ensure that at least 'atleast' hugepages are, and will remain, + * available to instantiate the first 'atleast' pages of the given + * inode. If the inode doesn't already have this many pages reserved + * or instantiated, set aside some hugepages in the reserved pool to + * satisfy later faults (or fail now if there aren't enough, rather + * than getting the SIGBUS later). + */ +int hugetlb_extend_reservation(struct hugetlbfs_inode_info *info, + unsigned long atleast) +{ + struct inode *inode = &info->vfs_inode; + unsigned long change_in_reserve = 0; + int ret = 0; spin_lock(&hugetlb_lock); - enqueue_huge_page(page); + read_lock_irq(&inode->i_mapping->tree_lock); + + if (info->prereserved_hpages >= atleast) + goto out; + + /* Because we always call this on shared mappings, none of the + * pages beyond info->prereserved_hpages can have been + * instantiated, so we need to reserve all of them now. */ + change_in_reserve = atleast - info->prereserved_hpages; + + if ((reserved_huge_pages + change_in_reserve) > free_huge_pages) { + ret = -ENOMEM; + goto out; + } + + reserved_huge_pages += change_in_reserve; + info->prereserved_hpages = atleast; + + out: + read_unlock_irq(&inode->i_mapping->tree_lock); spin_unlock(&hugetlb_lock); + + return ret; } -struct page *alloc_huge_page(struct vm_area_struct *vma, unsigned long addr) +/* hugetlb_truncate_reservation() + * + * This returns pages reserved for the given inode to the general free + * hugepage pool. If the inode has any pages prereserved, but not + * instantiated, beyond offset (atmost << HPAGE_SIZE), then release + * them. + */ +void hugetlb_truncate_reservation(struct hugetlbfs_inode_info *info, + unsigned long atmost) { + struct inode *inode = &info->vfs_inode; + struct address_space *mapping = inode->i_mapping; + unsigned long idx; + unsigned long change_in_reserve = 0; struct page *page; - int i; spin_lock(&hugetlb_lock); - page = dequeue_huge_page(vma, addr); - if (!page) { - spin_unlock(&hugetlb_lock); - return NULL; + read_lock_irq(&inode->i_mapping->tree_lock); + + if (info->prereserved_hpages <= atmost) + goto out; + + /* Count pages which were reserved, but not instantiated, and + * which we can now release. */ + for (idx = atmost; idx < info->prereserved_hpages; idx++) { + page = radix_tree_lookup(&mapping->page_tree, idx); + if (!page) + /* Pages which are already instantiated can't + * be unreserved (and in fact have already + * been removed from the reserved pool) */ + change_in_reserve++; } + + BUG_ON(reserved_huge_pages < change_in_reserve); + reserved_huge_pages -= change_in_reserve; + info->prereserved_hpages = atmost; + + out: + read_unlock_irq(&inode->i_mapping->tree_lock); spin_unlock(&hugetlb_lock); - set_page_count(page, 1); - page[1].lru.next = (void *)free_huge_page; /* set dtor */ - for (i = 0; i < (HPAGE_SIZE/PAGE_SIZE); ++i) - clear_user_highpage(&page[i], addr); - return page; } static int __init hugetlb_init(void) { unsigned long i; - struct page *page; if (HPAGE_SHIFT == 0) return 0; @@ -123,12 +266,8 @@ static int __init hugetlb_init(void) INIT_LIST_HEAD(&hugepage_freelists[i]); for (i = 0; i < max_huge_pages; ++i) { - page = alloc_fresh_huge_page(); - if (!page) + if (!alloc_fresh_huge_page()) break; - spin_lock(&hugetlb_lock); - enqueue_huge_page(page); - spin_unlock(&hugetlb_lock); } max_huge_pages = free_huge_pages = nr_huge_pages = i; printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages); @@ -154,9 +293,9 @@ static void update_and_free_page(struct page *page) page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | 1 << PG_private | 1<< PG_writeback); - set_page_count(&page[i], 0); } - set_page_count(page, 1); + page[1].lru.next = NULL; + set_page_refcounted(page); __free_pages(page, HUGETLB_PAGE_ORDER); } @@ -188,17 +327,14 @@ static inline void try_to_free_low(unsigned long count) static unsigned long set_max_huge_pages(unsigned long count) { while (count > nr_huge_pages) { - struct page *page = alloc_fresh_huge_page(); - if (!page) + if (!alloc_fresh_huge_page()) return nr_huge_pages; - spin_lock(&hugetlb_lock); - enqueue_huge_page(page); - spin_unlock(&hugetlb_lock); } if (count >= nr_huge_pages) return nr_huge_pages; spin_lock(&hugetlb_lock); + count = max(count, reserved_huge_pages); try_to_free_low(count); while (count < nr_huge_pages) { struct page *page = dequeue_huge_page(NULL, 0); @@ -225,9 +361,11 @@ int hugetlb_report_meminfo(char *buf) return sprintf(buf, "HugePages_Total: %5lu\n" "HugePages_Free: %5lu\n" + "HugePages_Rsvd: %5lu\n" "Hugepagesize: %5lu kB\n", nr_huge_pages, free_huge_pages, + reserved_huge_pages, HPAGE_SIZE/1024); } @@ -240,11 +378,6 @@ int hugetlb_report_node_meminfo(int nid, char *buf) nid, free_huge_pages_node[nid]); } -int is_hugepage_mem_enough(size_t size) -{ - return (size + ~HPAGE_MASK)/HPAGE_SIZE <= free_huge_pages; -} - /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ unsigned long hugetlb_total_pages(void) { @@ -374,7 +507,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long address, pte_t *ptep, pte_t pte) { struct page *old_page, *new_page; - int i, avoidcopy; + int avoidcopy; old_page = pte_page(pte); @@ -395,9 +528,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, } spin_unlock(&mm->page_table_lock); - for (i = 0; i < HPAGE_SIZE/PAGE_SIZE; i++) - copy_user_highpage(new_page + i, old_page + i, - address + i*PAGE_SIZE); + copy_huge_page(new_page, old_page, address); spin_lock(&mm->page_table_lock); ptep = huge_pte_offset(mm, address & HPAGE_MASK); @@ -442,6 +573,7 @@ retry: ret = VM_FAULT_OOM; goto out; } + clear_huge_page(page, address); if (vma->vm_flags & VM_SHARED) { int err; @@ -496,14 +628,24 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, pte_t *ptep; pte_t entry; int ret; + static DEFINE_MUTEX(hugetlb_instantiation_mutex); ptep = huge_pte_alloc(mm, address); if (!ptep) return VM_FAULT_OOM; + /* + * Serialize hugepage allocation and instantiation, so that we don't + * get spurious allocation failures if two CPUs race to instantiate + * the same page in the page cache. + */ + mutex_lock(&hugetlb_instantiation_mutex); entry = *ptep; - if (pte_none(entry)) - return hugetlb_no_page(mm, vma, address, ptep, write_access); + if (pte_none(entry)) { + ret = hugetlb_no_page(mm, vma, address, ptep, write_access); + mutex_unlock(&hugetlb_instantiation_mutex); + return ret; + } ret = VM_FAULT_MINOR; @@ -513,6 +655,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, if (write_access && !pte_write(entry)) ret = hugetlb_cow(mm, vma, address, ptep, entry); spin_unlock(&mm->page_table_lock); + mutex_unlock(&hugetlb_instantiation_mutex); return ret; } @@ -521,10 +664,10 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, struct page **pages, struct vm_area_struct **vmas, unsigned long *position, int *length, int i) { - unsigned long vpfn, vaddr = *position; + unsigned long pfn_offset; + unsigned long vaddr = *position; int remainder = *length; - vpfn = vaddr/PAGE_SIZE; spin_lock(&mm->page_table_lock); while (vaddr < vma->vm_end && remainder) { pte_t *pte; @@ -552,19 +695,29 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, break; } + pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT; + page = pte_page(*pte); +same_page: if (pages) { - page = &pte_page(*pte)[vpfn % (HPAGE_SIZE/PAGE_SIZE)]; get_page(page); - pages[i] = page; + pages[i] = page + pfn_offset; } if (vmas) vmas[i] = vma; vaddr += PAGE_SIZE; - ++vpfn; + ++pfn_offset; --remainder; ++i; + if (vaddr < vma->vm_end && remainder && + pfn_offset < HPAGE_SIZE/PAGE_SIZE) { + /* + * We use pfn_offset to avoid touching the pageframes + * of this compound page. + */ + goto same_page; + } } spin_unlock(&mm->page_table_lock); *length = remainder; @@ -572,3 +725,32 @@ int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, return i; } + +void hugetlb_change_protection(struct vm_area_struct *vma, + unsigned long address, unsigned long end, pgprot_t newprot) +{ + struct mm_struct *mm = vma->vm_mm; + unsigned long start = address; + pte_t *ptep; + pte_t pte; + + BUG_ON(address >= end); + flush_cache_range(vma, address, end); + + spin_lock(&mm->page_table_lock); + for (; address < end; address += HPAGE_SIZE) { + ptep = huge_pte_offset(mm, address); + if (!ptep) + continue; + if (!pte_none(*ptep)) { + pte = huge_ptep_get_and_clear(mm, address, ptep); + pte = pte_mkhuge(pte_modify(pte, newprot)); + set_huge_pte_at(mm, address, ptep, pte); + lazy_mmu_prot_update(pte); + } + } + spin_unlock(&mm->page_table_lock); + + flush_tlb_range(vma, start, end); +} +