| /* |
| * Generic hugetlb support. |
| * (C) William Irwin, April 2004 |
| */ |
| #include <linux/gfp.h> |
| #include <linux/list.h> |
| #include <linux/init.h> |
| #include <linux/module.h> |
| #include <linux/mm.h> |
| #include <linux/sysctl.h> |
| #include <linux/highmem.h> |
| #include <linux/nodemask.h> |
| #include <linux/pagemap.h> |
| #include <linux/mempolicy.h> |
| #include <linux/cpuset.h> |
| #include <linux/mutex.h> |
| |
| #include <asm/page.h> |
| #include <asm/pgtable.h> |
| |
| #include <linux/hugetlb.h> |
| #include "internal.h" |
| |
| const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; |
| static unsigned long nr_huge_pages, free_huge_pages, resv_huge_pages; |
| static unsigned long surplus_huge_pages; |
| static unsigned long nr_overcommit_huge_pages; |
| unsigned long max_huge_pages; |
| unsigned long sysctl_overcommit_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]; |
| static unsigned int surplus_huge_pages_node[MAX_NUMNODES]; |
| static gfp_t htlb_alloc_mask = GFP_HIGHUSER; |
| unsigned long hugepages_treat_as_movable; |
| static int hugetlb_next_nid; |
| |
| /* |
| * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages |
| */ |
| static DEFINE_SPINLOCK(hugetlb_lock); |
| |
| #define HPAGE_RESV_OWNER (1UL << (BITS_PER_LONG - 1)) |
| #define HPAGE_RESV_UNMAPPED (1UL << (BITS_PER_LONG - 2)) |
| #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) |
| /* |
| * These helpers are used to track how many pages are reserved for |
| * faults in a MAP_PRIVATE mapping. Only the process that called mmap() |
| * is guaranteed to have their future faults succeed. |
| * |
| * With the exception of reset_vma_resv_huge_pages() which is called at fork(), |
| * the reserve counters are updated with the hugetlb_lock held. It is safe |
| * to reset the VMA at fork() time as it is not in use yet and there is no |
| * chance of the global counters getting corrupted as a result of the values. |
| */ |
| static unsigned long vma_resv_huge_pages(struct vm_area_struct *vma) |
| { |
| VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
| if (!(vma->vm_flags & VM_SHARED)) |
| return (unsigned long)vma->vm_private_data & ~HPAGE_RESV_MASK; |
| return 0; |
| } |
| |
| static void set_vma_resv_huge_pages(struct vm_area_struct *vma, |
| unsigned long reserve) |
| { |
| unsigned long flags; |
| VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
| VM_BUG_ON(vma->vm_flags & VM_SHARED); |
| |
| flags = (unsigned long)vma->vm_private_data & HPAGE_RESV_MASK; |
| vma->vm_private_data = (void *)(reserve | flags); |
| } |
| |
| static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) |
| { |
| unsigned long reserveflags = (unsigned long)vma->vm_private_data; |
| VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
| vma->vm_private_data = (void *)(reserveflags | flags); |
| } |
| |
| static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) |
| { |
| VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
| return ((unsigned long)vma->vm_private_data & flag) != 0; |
| } |
| |
| /* Decrement the reserved pages in the hugepage pool by one */ |
| static void decrement_hugepage_resv_vma(struct vm_area_struct *vma) |
| { |
| if (vma->vm_flags & VM_SHARED) { |
| /* Shared mappings always use reserves */ |
| resv_huge_pages--; |
| } else { |
| /* |
| * Only the process that called mmap() has reserves for |
| * private mappings. |
| */ |
| if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { |
| unsigned long flags, reserve; |
| resv_huge_pages--; |
| flags = (unsigned long)vma->vm_private_data & |
| HPAGE_RESV_MASK; |
| reserve = (unsigned long)vma->vm_private_data - 1; |
| vma->vm_private_data = (void *)(reserve | flags); |
| } |
| } |
| } |
| |
| /* Reset counters to 0 and clear all HPAGE_RESV_* flags */ |
| void reset_vma_resv_huge_pages(struct vm_area_struct *vma) |
| { |
| VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
| if (!(vma->vm_flags & VM_SHARED)) |
| vma->vm_private_data = (void *)0; |
| } |
| |
| /* Returns true if the VMA has associated reserve pages */ |
| static int vma_has_private_reserves(struct vm_area_struct *vma) |
| { |
| if (vma->vm_flags & VM_SHARED) |
| return 0; |
| if (!vma_resv_huge_pages(vma)) |
| return 0; |
| return 1; |
| } |
| |
| 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 + i * PAGE_SIZE); |
| } |
| } |
| |
| static void copy_huge_page(struct page *dst, struct page *src, |
| unsigned long addr, struct vm_area_struct *vma) |
| { |
| 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, vma); |
| } |
| } |
| |
| static void enqueue_huge_page(struct page *page) |
| { |
| int nid = page_to_nid(page); |
| list_add(&page->lru, &hugepage_freelists[nid]); |
| free_huge_pages++; |
| free_huge_pages_node[nid]++; |
| } |
| |
| static struct page *dequeue_huge_page(void) |
| { |
| int nid; |
| struct page *page = NULL; |
| |
| for (nid = 0; nid < MAX_NUMNODES; ++nid) { |
| if (!list_empty(&hugepage_freelists[nid])) { |
| page = list_entry(hugepage_freelists[nid].next, |
| struct page, lru); |
| list_del(&page->lru); |
| free_huge_pages--; |
| free_huge_pages_node[nid]--; |
| break; |
| } |
| } |
| return page; |
| } |
| |
| static struct page *dequeue_huge_page_vma(struct vm_area_struct *vma, |
| unsigned long address, int avoid_reserve) |
| { |
| int nid; |
| struct page *page = NULL; |
| struct mempolicy *mpol; |
| nodemask_t *nodemask; |
| struct zonelist *zonelist = huge_zonelist(vma, address, |
| htlb_alloc_mask, &mpol, &nodemask); |
| struct zone *zone; |
| struct zoneref *z; |
| |
| /* |
| * A child process with MAP_PRIVATE mappings created by their parent |
| * have no page reserves. This check ensures that reservations are |
| * not "stolen". The child may still get SIGKILLed |
| */ |
| if (!vma_has_private_reserves(vma) && |
| free_huge_pages - resv_huge_pages == 0) |
| return NULL; |
| |
| /* If reserves cannot be used, ensure enough pages are in the pool */ |
| if (avoid_reserve && free_huge_pages - resv_huge_pages == 0) |
| return NULL; |
| |
| for_each_zone_zonelist_nodemask(zone, z, zonelist, |
| MAX_NR_ZONES - 1, nodemask) { |
| nid = zone_to_nid(zone); |
| if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) && |
| !list_empty(&hugepage_freelists[nid])) { |
| page = list_entry(hugepage_freelists[nid].next, |
| struct page, lru); |
| list_del(&page->lru); |
| free_huge_pages--; |
| free_huge_pages_node[nid]--; |
| |
| if (!avoid_reserve) |
| decrement_hugepage_resv_vma(vma); |
| |
| break; |
| } |
| } |
| mpol_cond_put(mpol); |
| return page; |
| } |
| |
| static void update_and_free_page(struct page *page) |
| { |
| int i; |
| nr_huge_pages--; |
| nr_huge_pages_node[page_to_nid(page)]--; |
| for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++) { |
| 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_compound_page_dtor(page, NULL); |
| set_page_refcounted(page); |
| arch_release_hugepage(page); |
| __free_pages(page, HUGETLB_PAGE_ORDER); |
| } |
| |
| static void free_huge_page(struct page *page) |
| { |
| int nid = page_to_nid(page); |
| struct address_space *mapping; |
| |
| mapping = (struct address_space *) page_private(page); |
| set_page_private(page, 0); |
| BUG_ON(page_count(page)); |
| INIT_LIST_HEAD(&page->lru); |
| |
| spin_lock(&hugetlb_lock); |
| if (surplus_huge_pages_node[nid]) { |
| update_and_free_page(page); |
| surplus_huge_pages--; |
| surplus_huge_pages_node[nid]--; |
| } else { |
| enqueue_huge_page(page); |
| } |
| spin_unlock(&hugetlb_lock); |
| if (mapping) |
| hugetlb_put_quota(mapping, 1); |
| } |
| |
| /* |
| * Increment or decrement surplus_huge_pages. Keep node-specific counters |
| * balanced by operating on them in a round-robin fashion. |
| * Returns 1 if an adjustment was made. |
| */ |
| static int adjust_pool_surplus(int delta) |
| { |
| static int prev_nid; |
| int nid = prev_nid; |
| int ret = 0; |
| |
| VM_BUG_ON(delta != -1 && delta != 1); |
| do { |
| nid = next_node(nid, node_online_map); |
| if (nid == MAX_NUMNODES) |
| nid = first_node(node_online_map); |
| |
| /* To shrink on this node, there must be a surplus page */ |
| if (delta < 0 && !surplus_huge_pages_node[nid]) |
| continue; |
| /* Surplus cannot exceed the total number of pages */ |
| if (delta > 0 && surplus_huge_pages_node[nid] >= |
| nr_huge_pages_node[nid]) |
| continue; |
| |
| surplus_huge_pages += delta; |
| surplus_huge_pages_node[nid] += delta; |
| ret = 1; |
| break; |
| } while (nid != prev_nid); |
| |
| prev_nid = nid; |
| return ret; |
| } |
| |
| static struct page *alloc_fresh_huge_page_node(int nid) |
| { |
| struct page *page; |
| |
| page = alloc_pages_node(nid, |
| htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| |
| __GFP_REPEAT|__GFP_NOWARN, |
| HUGETLB_PAGE_ORDER); |
| if (page) { |
| if (arch_prepare_hugepage(page)) { |
| __free_pages(page, HUGETLB_PAGE_ORDER); |
| return NULL; |
| } |
| set_compound_page_dtor(page, free_huge_page); |
| spin_lock(&hugetlb_lock); |
| nr_huge_pages++; |
| nr_huge_pages_node[nid]++; |
| spin_unlock(&hugetlb_lock); |
| put_page(page); /* free it into the hugepage allocator */ |
| } |
| |
| return page; |
| } |
| |
| static int alloc_fresh_huge_page(void) |
| { |
| struct page *page; |
| int start_nid; |
| int next_nid; |
| int ret = 0; |
| |
| start_nid = hugetlb_next_nid; |
| |
| do { |
| page = alloc_fresh_huge_page_node(hugetlb_next_nid); |
| if (page) |
| ret = 1; |
| /* |
| * Use a helper variable to find the next node and then |
| * copy it back to hugetlb_next_nid afterwards: |
| * otherwise there's a window in which a racer might |
| * pass invalid nid MAX_NUMNODES to alloc_pages_node. |
| * But we don't need to use a spin_lock here: it really |
| * doesn't matter if occasionally a racer chooses the |
| * same nid as we do. Move nid forward in the mask even |
| * if we just successfully allocated a hugepage so that |
| * the next caller gets hugepages on the next node. |
| */ |
| next_nid = next_node(hugetlb_next_nid, node_online_map); |
| if (next_nid == MAX_NUMNODES) |
| next_nid = first_node(node_online_map); |
| hugetlb_next_nid = next_nid; |
| } while (!page && hugetlb_next_nid != start_nid); |
| |
| if (ret) |
| count_vm_event(HTLB_BUDDY_PGALLOC); |
| else |
| count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); |
| |
| return ret; |
| } |
| |
| static struct page *alloc_buddy_huge_page(struct vm_area_struct *vma, |
| unsigned long address) |
| { |
| struct page *page; |
| unsigned int nid; |
| |
| /* |
| * Assume we will successfully allocate the surplus page to |
| * prevent racing processes from causing the surplus to exceed |
| * overcommit |
| * |
| * This however introduces a different race, where a process B |
| * tries to grow the static hugepage pool while alloc_pages() is |
| * called by process A. B will only examine the per-node |
| * counters in determining if surplus huge pages can be |
| * converted to normal huge pages in adjust_pool_surplus(). A |
| * won't be able to increment the per-node counter, until the |
| * lock is dropped by B, but B doesn't drop hugetlb_lock until |
| * no more huge pages can be converted from surplus to normal |
| * state (and doesn't try to convert again). Thus, we have a |
| * case where a surplus huge page exists, the pool is grown, and |
| * the surplus huge page still exists after, even though it |
| * should just have been converted to a normal huge page. This |
| * does not leak memory, though, as the hugepage will be freed |
| * once it is out of use. It also does not allow the counters to |
| * go out of whack in adjust_pool_surplus() as we don't modify |
| * the node values until we've gotten the hugepage and only the |
| * per-node value is checked there. |
| */ |
| spin_lock(&hugetlb_lock); |
| if (surplus_huge_pages >= nr_overcommit_huge_pages) { |
| spin_unlock(&hugetlb_lock); |
| return NULL; |
| } else { |
| nr_huge_pages++; |
| surplus_huge_pages++; |
| } |
| spin_unlock(&hugetlb_lock); |
| |
| page = alloc_pages(htlb_alloc_mask|__GFP_COMP| |
| __GFP_REPEAT|__GFP_NOWARN, |
| HUGETLB_PAGE_ORDER); |
| |
| spin_lock(&hugetlb_lock); |
| if (page) { |
| /* |
| * This page is now managed by the hugetlb allocator and has |
| * no users -- drop the buddy allocator's reference. |
| */ |
| put_page_testzero(page); |
| VM_BUG_ON(page_count(page)); |
| nid = page_to_nid(page); |
| set_compound_page_dtor(page, free_huge_page); |
| /* |
| * We incremented the global counters already |
| */ |
| nr_huge_pages_node[nid]++; |
| surplus_huge_pages_node[nid]++; |
| __count_vm_event(HTLB_BUDDY_PGALLOC); |
| } else { |
| nr_huge_pages--; |
| surplus_huge_pages--; |
| __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); |
| } |
| spin_unlock(&hugetlb_lock); |
| |
| return page; |
| } |
| |
| /* |
| * Increase the hugetlb pool such that it can accomodate a reservation |
| * of size 'delta'. |
| */ |
| static int gather_surplus_pages(int delta) |
| { |
| struct list_head surplus_list; |
| struct page *page, *tmp; |
| int ret, i; |
| int needed, allocated; |
| |
| needed = (resv_huge_pages + delta) - free_huge_pages; |
| if (needed <= 0) { |
| resv_huge_pages += delta; |
| return 0; |
| } |
| |
| allocated = 0; |
| INIT_LIST_HEAD(&surplus_list); |
| |
| ret = -ENOMEM; |
| retry: |
| spin_unlock(&hugetlb_lock); |
| for (i = 0; i < needed; i++) { |
| page = alloc_buddy_huge_page(NULL, 0); |
| if (!page) { |
| /* |
| * We were not able to allocate enough pages to |
| * satisfy the entire reservation so we free what |
| * we've allocated so far. |
| */ |
| spin_lock(&hugetlb_lock); |
| needed = 0; |
| goto free; |
| } |
| |
| list_add(&page->lru, &surplus_list); |
| } |
| allocated += needed; |
| |
| /* |
| * After retaking hugetlb_lock, we need to recalculate 'needed' |
| * because either resv_huge_pages or free_huge_pages may have changed. |
| */ |
| spin_lock(&hugetlb_lock); |
| needed = (resv_huge_pages + delta) - (free_huge_pages + allocated); |
| if (needed > 0) |
| goto retry; |
| |
| /* |
| * The surplus_list now contains _at_least_ the number of extra pages |
| * needed to accomodate the reservation. Add the appropriate number |
| * of pages to the hugetlb pool and free the extras back to the buddy |
| * allocator. Commit the entire reservation here to prevent another |
| * process from stealing the pages as they are added to the pool but |
| * before they are reserved. |
| */ |
| needed += allocated; |
| resv_huge_pages += delta; |
| ret = 0; |
| free: |
| /* Free the needed pages to the hugetlb pool */ |
| list_for_each_entry_safe(page, tmp, &surplus_list, lru) { |
| if ((--needed) < 0) |
| break; |
| list_del(&page->lru); |
| enqueue_huge_page(page); |
| } |
| |
| /* Free unnecessary surplus pages to the buddy allocator */ |
| if (!list_empty(&surplus_list)) { |
| spin_unlock(&hugetlb_lock); |
| list_for_each_entry_safe(page, tmp, &surplus_list, lru) { |
| list_del(&page->lru); |
| /* |
| * The page has a reference count of zero already, so |
| * call free_huge_page directly instead of using |
| * put_page. This must be done with hugetlb_lock |
| * unlocked which is safe because free_huge_page takes |
| * hugetlb_lock before deciding how to free the page. |
| */ |
| free_huge_page(page); |
| } |
| spin_lock(&hugetlb_lock); |
| } |
| |
| return ret; |
| } |
| |
| /* |
| * When releasing a hugetlb pool reservation, any surplus pages that were |
| * allocated to satisfy the reservation must be explicitly freed if they were |
| * never used. |
| */ |
| static void return_unused_surplus_pages(unsigned long unused_resv_pages) |
| { |
| static int nid = -1; |
| struct page *page; |
| unsigned long nr_pages; |
| |
| /* |
| * We want to release as many surplus pages as possible, spread |
| * evenly across all nodes. Iterate across all nodes until we |
| * can no longer free unreserved surplus pages. This occurs when |
| * the nodes with surplus pages have no free pages. |
| */ |
| unsigned long remaining_iterations = num_online_nodes(); |
| |
| /* Uncommit the reservation */ |
| resv_huge_pages -= unused_resv_pages; |
| |
| nr_pages = min(unused_resv_pages, surplus_huge_pages); |
| |
| while (remaining_iterations-- && nr_pages) { |
| nid = next_node(nid, node_online_map); |
| if (nid == MAX_NUMNODES) |
| nid = first_node(node_online_map); |
| |
| if (!surplus_huge_pages_node[nid]) |
| continue; |
| |
| if (!list_empty(&hugepage_freelists[nid])) { |
| page = list_entry(hugepage_freelists[nid].next, |
| struct page, lru); |
| list_del(&page->lru); |
| update_and_free_page(page); |
| free_huge_pages--; |
| free_huge_pages_node[nid]--; |
| surplus_huge_pages--; |
| surplus_huge_pages_node[nid]--; |
| nr_pages--; |
| remaining_iterations = num_online_nodes(); |
| } |
| } |
| } |
| |
| static struct page *alloc_huge_page(struct vm_area_struct *vma, |
| unsigned long addr, int avoid_reserve) |
| { |
| struct page *page; |
| struct address_space *mapping = vma->vm_file->f_mapping; |
| struct inode *inode = mapping->host; |
| unsigned int chg = 0; |
| |
| /* |
| * Processes that did not create the mapping will have no reserves and |
| * will not have accounted against quota. Check that the quota can be |
| * made before satisfying the allocation |
| */ |
| if (!(vma->vm_flags & VM_SHARED) && |
| !is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { |
| chg = 1; |
| if (hugetlb_get_quota(inode->i_mapping, chg)) |
| return ERR_PTR(-ENOSPC); |
| } |
| |
| spin_lock(&hugetlb_lock); |
| page = dequeue_huge_page_vma(vma, addr, avoid_reserve); |
| spin_unlock(&hugetlb_lock); |
| |
| if (!page) { |
| page = alloc_buddy_huge_page(vma, addr); |
| if (!page) { |
| hugetlb_put_quota(inode->i_mapping, chg); |
| return ERR_PTR(-VM_FAULT_OOM); |
| } |
| } |
| |
| set_page_refcounted(page); |
| set_page_private(page, (unsigned long) mapping); |
| |
| return page; |
| } |
| |
| static int __init hugetlb_init(void) |
| { |
| unsigned long i; |
| |
| if (HPAGE_SHIFT == 0) |
| return 0; |
| |
| for (i = 0; i < MAX_NUMNODES; ++i) |
| INIT_LIST_HEAD(&hugepage_freelists[i]); |
| |
| hugetlb_next_nid = first_node(node_online_map); |
| |
| for (i = 0; i < max_huge_pages; ++i) { |
| if (!alloc_fresh_huge_page()) |
| break; |
| } |
| max_huge_pages = free_huge_pages = nr_huge_pages = i; |
| printk("Total HugeTLB memory allocated, %ld\n", free_huge_pages); |
| return 0; |
| } |
| module_init(hugetlb_init); |
| |
| static int __init hugetlb_setup(char *s) |
| { |
| if (sscanf(s, "%lu", &max_huge_pages) <= 0) |
| max_huge_pages = 0; |
| return 1; |
| } |
| __setup("hugepages=", hugetlb_setup); |
| |
| static unsigned int cpuset_mems_nr(unsigned int *array) |
| { |
| int node; |
| unsigned int nr = 0; |
| |
| for_each_node_mask(node, cpuset_current_mems_allowed) |
| nr += array[node]; |
| |
| return nr; |
| } |
| |
| #ifdef CONFIG_SYSCTL |
| #ifdef CONFIG_HIGHMEM |
| static void try_to_free_low(unsigned long count) |
| { |
| int i; |
| |
| for (i = 0; i < MAX_NUMNODES; ++i) { |
| struct page *page, *next; |
| list_for_each_entry_safe(page, next, &hugepage_freelists[i], lru) { |
| if (count >= nr_huge_pages) |
| return; |
| if (PageHighMem(page)) |
| continue; |
| list_del(&page->lru); |
| update_and_free_page(page); |
| free_huge_pages--; |
| free_huge_pages_node[page_to_nid(page)]--; |
| } |
| } |
| } |
| #else |
| static inline void try_to_free_low(unsigned long count) |
| { |
| } |
| #endif |
| |
| #define persistent_huge_pages (nr_huge_pages - surplus_huge_pages) |
| static unsigned long set_max_huge_pages(unsigned long count) |
| { |
| unsigned long min_count, ret; |
| |
| /* |
| * Increase the pool size |
| * First take pages out of surplus state. Then make up the |
| * remaining difference by allocating fresh huge pages. |
| * |
| * We might race with alloc_buddy_huge_page() here and be unable |
| * to convert a surplus huge page to a normal huge page. That is |
| * not critical, though, it just means the overall size of the |
| * pool might be one hugepage larger than it needs to be, but |
| * within all the constraints specified by the sysctls. |
| */ |
| spin_lock(&hugetlb_lock); |
| while (surplus_huge_pages && count > persistent_huge_pages) { |
| if (!adjust_pool_surplus(-1)) |
| break; |
| } |
| |
| while (count > persistent_huge_pages) { |
| /* |
| * If this allocation races such that we no longer need the |
| * page, free_huge_page will handle it by freeing the page |
| * and reducing the surplus. |
| */ |
| spin_unlock(&hugetlb_lock); |
| ret = alloc_fresh_huge_page(); |
| spin_lock(&hugetlb_lock); |
| if (!ret) |
| goto out; |
| |
| } |
| |
| /* |
| * Decrease the pool size |
| * First return free pages to the buddy allocator (being careful |
| * to keep enough around to satisfy reservations). Then place |
| * pages into surplus state as needed so the pool will shrink |
| * to the desired size as pages become free. |
| * |
| * By placing pages into the surplus state independent of the |
| * overcommit value, we are allowing the surplus pool size to |
| * exceed overcommit. There are few sane options here. Since |
| * alloc_buddy_huge_page() is checking the global counter, |
| * though, we'll note that we're not allowed to exceed surplus |
| * and won't grow the pool anywhere else. Not until one of the |
| * sysctls are changed, or the surplus pages go out of use. |
| */ |
| min_count = resv_huge_pages + nr_huge_pages - free_huge_pages; |
| min_count = max(count, min_count); |
| try_to_free_low(min_count); |
| while (min_count < persistent_huge_pages) { |
| struct page *page = dequeue_huge_page(); |
| if (!page) |
| break; |
| update_and_free_page(page); |
| } |
| while (count < persistent_huge_pages) { |
| if (!adjust_pool_surplus(1)) |
| break; |
| } |
| out: |
| ret = persistent_huge_pages; |
| spin_unlock(&hugetlb_lock); |
| return ret; |
| } |
| |
| int hugetlb_sysctl_handler(struct ctl_table *table, int write, |
| struct file *file, void __user *buffer, |
| size_t *length, loff_t *ppos) |
| { |
| proc_doulongvec_minmax(table, write, file, buffer, length, ppos); |
| max_huge_pages = set_max_huge_pages(max_huge_pages); |
| return 0; |
| } |
| |
| int hugetlb_treat_movable_handler(struct ctl_table *table, int write, |
| struct file *file, void __user *buffer, |
| size_t *length, loff_t *ppos) |
| { |
| proc_dointvec(table, write, file, buffer, length, ppos); |
| if (hugepages_treat_as_movable) |
| htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; |
| else |
| htlb_alloc_mask = GFP_HIGHUSER; |
| return 0; |
| } |
| |
| int hugetlb_overcommit_handler(struct ctl_table *table, int write, |
| struct file *file, void __user *buffer, |
| size_t *length, loff_t *ppos) |
| { |
| proc_doulongvec_minmax(table, write, file, buffer, length, ppos); |
| spin_lock(&hugetlb_lock); |
| nr_overcommit_huge_pages = sysctl_overcommit_huge_pages; |
| spin_unlock(&hugetlb_lock); |
| return 0; |
| } |
| |
| #endif /* CONFIG_SYSCTL */ |
| |
| int hugetlb_report_meminfo(char *buf) |
| { |
| return sprintf(buf, |
| "HugePages_Total: %5lu\n" |
| "HugePages_Free: %5lu\n" |
| "HugePages_Rsvd: %5lu\n" |
| "HugePages_Surp: %5lu\n" |
| "Hugepagesize: %5lu kB\n", |
| nr_huge_pages, |
| free_huge_pages, |
| resv_huge_pages, |
| surplus_huge_pages, |
| HPAGE_SIZE/1024); |
| } |
| |
| int hugetlb_report_node_meminfo(int nid, char *buf) |
| { |
| return sprintf(buf, |
| "Node %d HugePages_Total: %5u\n" |
| "Node %d HugePages_Free: %5u\n" |
| "Node %d HugePages_Surp: %5u\n", |
| nid, nr_huge_pages_node[nid], |
| nid, free_huge_pages_node[nid], |
| nid, surplus_huge_pages_node[nid]); |
| } |
| |
| /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ |
| unsigned long hugetlb_total_pages(void) |
| { |
| return nr_huge_pages * (HPAGE_SIZE / PAGE_SIZE); |
| } |
| |
| static int hugetlb_acct_memory(long delta) |
| { |
| int ret = -ENOMEM; |
| |
| spin_lock(&hugetlb_lock); |
| /* |
| * When cpuset is configured, it breaks the strict hugetlb page |
| * reservation as the accounting is done on a global variable. Such |
| * reservation is completely rubbish in the presence of cpuset because |
| * the reservation is not checked against page availability for the |
| * current cpuset. Application can still potentially OOM'ed by kernel |
| * with lack of free htlb page in cpuset that the task is in. |
| * Attempt to enforce strict accounting with cpuset is almost |
| * impossible (or too ugly) because cpuset is too fluid that |
| * task or memory node can be dynamically moved between cpusets. |
| * |
| * The change of semantics for shared hugetlb mapping with cpuset is |
| * undesirable. However, in order to preserve some of the semantics, |
| * we fall back to check against current free page availability as |
| * a best attempt and hopefully to minimize the impact of changing |
| * semantics that cpuset has. |
| */ |
| if (delta > 0) { |
| if (gather_surplus_pages(delta) < 0) |
| goto out; |
| |
| if (delta > cpuset_mems_nr(free_huge_pages_node)) { |
| return_unused_surplus_pages(delta); |
| goto out; |
| } |
| } |
| |
| ret = 0; |
| if (delta < 0) |
| return_unused_surplus_pages((unsigned long) -delta); |
| |
| out: |
| spin_unlock(&hugetlb_lock); |
| return ret; |
| } |
| |
| static void hugetlb_vm_op_close(struct vm_area_struct *vma) |
| { |
| unsigned long reserve = vma_resv_huge_pages(vma); |
| if (reserve) |
| hugetlb_acct_memory(-reserve); |
| } |
| |
| /* |
| * We cannot handle pagefaults against hugetlb pages at all. They cause |
| * handle_mm_fault() to try to instantiate regular-sized pages in the |
| * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get |
| * this far. |
| */ |
| static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
| { |
| BUG(); |
| return 0; |
| } |
| |
| struct vm_operations_struct hugetlb_vm_ops = { |
| .fault = hugetlb_vm_op_fault, |
| .close = hugetlb_vm_op_close, |
| }; |
| |
| static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, |
| int writable) |
| { |
| pte_t entry; |
| |
| if (writable) { |
| entry = |
| pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); |
| } else { |
| entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot)); |
| } |
| entry = pte_mkyoung(entry); |
| entry = pte_mkhuge(entry); |
| |
| return entry; |
| } |
| |
| static void set_huge_ptep_writable(struct vm_area_struct *vma, |
| unsigned long address, pte_t *ptep) |
| { |
| pte_t entry; |
| |
| entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep))); |
| if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) { |
| update_mmu_cache(vma, address, entry); |
| } |
| } |
| |
| |
| int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, |
| struct vm_area_struct *vma) |
| { |
| pte_t *src_pte, *dst_pte, entry; |
| struct page *ptepage; |
| unsigned long addr; |
| int cow; |
| |
| cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; |
| |
| for (addr = vma->vm_start; addr < vma->vm_end; addr += HPAGE_SIZE) { |
| src_pte = huge_pte_offset(src, addr); |
| if (!src_pte) |
| continue; |
| dst_pte = huge_pte_alloc(dst, addr); |
| if (!dst_pte) |
| goto nomem; |
| |
| /* If the pagetables are shared don't copy or take references */ |
| if (dst_pte == src_pte) |
| continue; |
| |
| spin_lock(&dst->page_table_lock); |
| spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); |
| if (!huge_pte_none(huge_ptep_get(src_pte))) { |
| if (cow) |
| huge_ptep_set_wrprotect(src, addr, src_pte); |
| entry = huge_ptep_get(src_pte); |
| ptepage = pte_page(entry); |
| get_page(ptepage); |
| set_huge_pte_at(dst, addr, dst_pte, entry); |
| } |
| spin_unlock(&src->page_table_lock); |
| spin_unlock(&dst->page_table_lock); |
| } |
| return 0; |
| |
| nomem: |
| return -ENOMEM; |
| } |
| |
| void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
| unsigned long end, struct page *ref_page) |
| { |
| struct mm_struct *mm = vma->vm_mm; |
| unsigned long address; |
| pte_t *ptep; |
| pte_t pte; |
| struct page *page; |
| struct page *tmp; |
| /* |
| * A page gathering list, protected by per file i_mmap_lock. The |
| * lock is used to avoid list corruption from multiple unmapping |
| * of the same page since we are using page->lru. |
| */ |
| LIST_HEAD(page_list); |
| |
| WARN_ON(!is_vm_hugetlb_page(vma)); |
| BUG_ON(start & ~HPAGE_MASK); |
| BUG_ON(end & ~HPAGE_MASK); |
| |
| spin_lock(&mm->page_table_lock); |
| for (address = start; address < end; address += HPAGE_SIZE) { |
| ptep = huge_pte_offset(mm, address); |
| if (!ptep) |
| continue; |
| |
| if (huge_pmd_unshare(mm, &address, ptep)) |
| continue; |
| |
| /* |
| * If a reference page is supplied, it is because a specific |
| * page is being unmapped, not a range. Ensure the page we |
| * are about to unmap is the actual page of interest. |
| */ |
| if (ref_page) { |
| pte = huge_ptep_get(ptep); |
| if (huge_pte_none(pte)) |
| continue; |
| page = pte_page(pte); |
| if (page != ref_page) |
| continue; |
| |
| /* |
| * Mark the VMA as having unmapped its page so that |
| * future faults in this VMA will fail rather than |
| * looking like data was lost |
| */ |
| set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); |
| } |
| |
| pte = huge_ptep_get_and_clear(mm, address, ptep); |
| if (huge_pte_none(pte)) |
| continue; |
| |
| page = pte_page(pte); |
| if (pte_dirty(pte)) |
| set_page_dirty(page); |
| list_add(&page->lru, &page_list); |
| } |
| spin_unlock(&mm->page_table_lock); |
| flush_tlb_range(vma, start, end); |
| list_for_each_entry_safe(page, tmp, &page_list, lru) { |
| list_del(&page->lru); |
| put_page(page); |
| } |
| } |
| |
| void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
| unsigned long end, struct page *ref_page) |
| { |
| /* |
| * It is undesirable to test vma->vm_file as it should be non-null |
| * for valid hugetlb area. However, vm_file will be NULL in the error |
| * cleanup path of do_mmap_pgoff. When hugetlbfs ->mmap method fails, |
| * do_mmap_pgoff() nullifies vma->vm_file before calling this function |
| * to clean up. Since no pte has actually been setup, it is safe to |
| * do nothing in this case. |
| */ |
| if (vma->vm_file) { |
| spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); |
| __unmap_hugepage_range(vma, start, end, ref_page); |
| spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); |
| } |
| } |
| |
| /* |
| * This is called when the original mapper is failing to COW a MAP_PRIVATE |
| * mappping it owns the reserve page for. The intention is to unmap the page |
| * from other VMAs and let the children be SIGKILLed if they are faulting the |
| * same region. |
| */ |
| int unmap_ref_private(struct mm_struct *mm, |
| struct vm_area_struct *vma, |
| struct page *page, |
| unsigned long address) |
| { |
| struct vm_area_struct *iter_vma; |
| struct address_space *mapping; |
| struct prio_tree_iter iter; |
| pgoff_t pgoff; |
| |
| /* |
| * vm_pgoff is in PAGE_SIZE units, hence the different calculation |
| * from page cache lookup which is in HPAGE_SIZE units. |
| */ |
| address = address & huge_page_mask(hstate_vma(vma)); |
| pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) |
| + (vma->vm_pgoff >> PAGE_SHIFT); |
| mapping = (struct address_space *)page_private(page); |
| |
| vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) { |
| /* Do not unmap the current VMA */ |
| if (iter_vma == vma) |
| continue; |
| |
| /* |
| * Unmap the page from other VMAs without their own reserves. |
| * They get marked to be SIGKILLed if they fault in these |
| * areas. This is because a future no-page fault on this VMA |
| * could insert a zeroed page instead of the data existing |
| * from the time of fork. This would look like data corruption |
| */ |
| if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) |
| unmap_hugepage_range(iter_vma, |
| address, address + HPAGE_SIZE, |
| page); |
| } |
| |
| return 1; |
| } |
| |
| static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, |
| unsigned long address, pte_t *ptep, pte_t pte, |
| struct page *pagecache_page) |
| { |
| struct page *old_page, *new_page; |
| int avoidcopy; |
| int outside_reserve = 0; |
| |
| old_page = pte_page(pte); |
| |
| retry_avoidcopy: |
| /* If no-one else is actually using this page, avoid the copy |
| * and just make the page writable */ |
| avoidcopy = (page_count(old_page) == 1); |
| if (avoidcopy) { |
| set_huge_ptep_writable(vma, address, ptep); |
| return 0; |
| } |
| |
| /* |
| * If the process that created a MAP_PRIVATE mapping is about to |
| * perform a COW due to a shared page count, attempt to satisfy |
| * the allocation without using the existing reserves. The pagecache |
| * page is used to determine if the reserve at this address was |
| * consumed or not. If reserves were used, a partial faulted mapping |
| * at the time of fork() could consume its reserves on COW instead |
| * of the full address range. |
| */ |
| if (!(vma->vm_flags & VM_SHARED) && |
| is_vma_resv_set(vma, HPAGE_RESV_OWNER) && |
| old_page != pagecache_page) |
| outside_reserve = 1; |
| |
| page_cache_get(old_page); |
| new_page = alloc_huge_page(vma, address, outside_reserve); |
| |
| if (IS_ERR(new_page)) { |
| page_cache_release(old_page); |
| |
| /* |
| * If a process owning a MAP_PRIVATE mapping fails to COW, |
| * it is due to references held by a child and an insufficient |
| * huge page pool. To guarantee the original mappers |
| * reliability, unmap the page from child processes. The child |
| * may get SIGKILLed if it later faults. |
| */ |
| if (outside_reserve) { |
| BUG_ON(huge_pte_none(pte)); |
| if (unmap_ref_private(mm, vma, old_page, address)) { |
| BUG_ON(page_count(old_page) != 1); |
| BUG_ON(huge_pte_none(pte)); |
| goto retry_avoidcopy; |
| } |
| WARN_ON_ONCE(1); |
| } |
| |
| return -PTR_ERR(new_page); |
| } |
| |
| spin_unlock(&mm->page_table_lock); |
| copy_huge_page(new_page, old_page, address, vma); |
| __SetPageUptodate(new_page); |
| spin_lock(&mm->page_table_lock); |
| |
| ptep = huge_pte_offset(mm, address & HPAGE_MASK); |
| if (likely(pte_same(huge_ptep_get(ptep), pte))) { |
| /* Break COW */ |
| huge_ptep_clear_flush(vma, address, ptep); |
| set_huge_pte_at(mm, address, ptep, |
| make_huge_pte(vma, new_page, 1)); |
| /* Make the old page be freed below */ |
| new_page = old_page; |
| } |
| page_cache_release(new_page); |
| page_cache_release(old_page); |
| return 0; |
| } |
| |
| /* Return the pagecache page at a given address within a VMA */ |
| static struct page *hugetlbfs_pagecache_page(struct vm_area_struct *vma, |
| unsigned long address) |
| { |
| struct address_space *mapping; |
| unsigned long idx; |
| |
| mapping = vma->vm_file->f_mapping; |
| idx = ((address - vma->vm_start) >> HPAGE_SHIFT) |
| + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT)); |
| |
| return find_lock_page(mapping, idx); |
| } |
| |
| static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| unsigned long address, pte_t *ptep, int write_access) |
| { |
| int ret = VM_FAULT_SIGBUS; |
| unsigned long idx; |
| unsigned long size; |
| struct page *page; |
| struct address_space *mapping; |
| pte_t new_pte; |
| |
| /* |
| * Currently, we are forced to kill the process in the event the |
| * original mapper has unmapped pages from the child due to a failed |
| * COW. Warn that such a situation has occured as it may not be obvious |
| */ |
| if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { |
| printk(KERN_WARNING |
| "PID %d killed due to inadequate hugepage pool\n", |
| current->pid); |
| return ret; |
| } |
| |
| mapping = vma->vm_file->f_mapping; |
| idx = ((address - vma->vm_start) >> HPAGE_SHIFT) |
| + (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT)); |
| |
| /* |
| * Use page lock to guard against racing truncation |
| * before we get page_table_lock. |
| */ |
| retry: |
| page = find_lock_page(mapping, idx); |
| if (!page) { |
| size = i_size_read(mapping->host) >> HPAGE_SHIFT; |
| if (idx >= size) |
| goto out; |
| page = alloc_huge_page(vma, address, 0); |
| if (IS_ERR(page)) { |
| ret = -PTR_ERR(page); |
| goto out; |
| } |
| clear_huge_page(page, address); |
| __SetPageUptodate(page); |
| |
| if (vma->vm_flags & VM_SHARED) { |
| int err; |
| struct inode *inode = mapping->host; |
| |
| err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); |
| if (err) { |
| put_page(page); |
| if (err == -EEXIST) |
| goto retry; |
| goto out; |
| } |
| |
| spin_lock(&inode->i_lock); |
| inode->i_blocks += BLOCKS_PER_HUGEPAGE; |
| spin_unlock(&inode->i_lock); |
| } else |
| lock_page(page); |
| } |
| |
| spin_lock(&mm->page_table_lock); |
| size = i_size_read(mapping->host) >> HPAGE_SHIFT; |
| if (idx >= size) |
| goto backout; |
| |
| ret = 0; |
| if (!huge_pte_none(huge_ptep_get(ptep))) |
| goto backout; |
| |
| new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) |
| && (vma->vm_flags & VM_SHARED))); |
| set_huge_pte_at(mm, address, ptep, new_pte); |
| |
| if (write_access && !(vma->vm_flags & VM_SHARED)) { |
| /* Optimization, do the COW without a second fault */ |
| ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page); |
| } |
| |
| spin_unlock(&mm->page_table_lock); |
| unlock_page(page); |
| out: |
| return ret; |
| |
| backout: |
| spin_unlock(&mm->page_table_lock); |
| unlock_page(page); |
| put_page(page); |
| goto out; |
| } |
| |
| int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
| unsigned long address, int write_access) |
| { |
| 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 = huge_ptep_get(ptep); |
| if (huge_pte_none(entry)) { |
| ret = hugetlb_no_page(mm, vma, address, ptep, write_access); |
| mutex_unlock(&hugetlb_instantiation_mutex); |
| return ret; |
| } |
| |
| ret = 0; |
| |
| spin_lock(&mm->page_table_lock); |
| /* Check for a racing update before calling hugetlb_cow */ |
| if (likely(pte_same(entry, huge_ptep_get(ptep)))) |
| if (write_access && !pte_write(entry)) { |
| struct page *page; |
| page = hugetlbfs_pagecache_page(vma, address); |
| ret = hugetlb_cow(mm, vma, address, ptep, entry, page); |
| if (page) { |
| unlock_page(page); |
| put_page(page); |
| } |
| } |
| spin_unlock(&mm->page_table_lock); |
| mutex_unlock(&hugetlb_instantiation_mutex); |
| |
| return ret; |
| } |
| |
| 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, |
| int write) |
| { |
| unsigned long pfn_offset; |
| unsigned long vaddr = *position; |
| int remainder = *length; |
| |
| spin_lock(&mm->page_table_lock); |
| while (vaddr < vma->vm_end && remainder) { |
| pte_t *pte; |
| struct page *page; |
| |
| /* |
| * Some archs (sparc64, sh*) have multiple pte_ts to |
| * each hugepage. We have to make * sure we get the |
| * first, for the page indexing below to work. |
| */ |
| pte = huge_pte_offset(mm, vaddr & HPAGE_MASK); |
| |
| if (!pte || huge_pte_none(huge_ptep_get(pte)) || |
| (write && !pte_write(huge_ptep_get(pte)))) { |
| int ret; |
| |
| spin_unlock(&mm->page_table_lock); |
| ret = hugetlb_fault(mm, vma, vaddr, write); |
| spin_lock(&mm->page_table_lock); |
| if (!(ret & VM_FAULT_ERROR)) |
| continue; |
| |
| remainder = 0; |
| if (!i) |
| i = -EFAULT; |
| break; |
| } |
| |
| pfn_offset = (vaddr & ~HPAGE_MASK) >> PAGE_SHIFT; |
| page = pte_page(huge_ptep_get(pte)); |
| same_page: |
| if (pages) { |
| get_page(page); |
| pages[i] = page + pfn_offset; |
| } |
| |
| if (vmas) |
| vmas[i] = vma; |
| |
| vaddr += PAGE_SIZE; |
| ++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; |
| *position = vaddr; |
| |
| 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(&vma->vm_file->f_mapping->i_mmap_lock); |
| spin_lock(&mm->page_table_lock); |
| for (; address < end; address += HPAGE_SIZE) { |
| ptep = huge_pte_offset(mm, address); |
| if (!ptep) |
| continue; |
| if (huge_pmd_unshare(mm, &address, ptep)) |
| continue; |
| if (!huge_pte_none(huge_ptep_get(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); |
| } |
| } |
| spin_unlock(&mm->page_table_lock); |
| spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); |
| |
| flush_tlb_range(vma, start, end); |
| } |
| |
| struct file_region { |
| struct list_head link; |
| long from; |
| long to; |
| }; |
| |
| static long region_add(struct list_head *head, long f, long t) |
| { |
| struct file_region *rg, *nrg, *trg; |
| |
| /* Locate the region we are either in or before. */ |
| list_for_each_entry(rg, head, link) |
| if (f <= rg->to) |
| break; |
| |
| /* Round our left edge to the current segment if it encloses us. */ |
| if (f > rg->from) |
| f = rg->from; |
| |
| /* Check for and consume any regions we now overlap with. */ |
| nrg = rg; |
| list_for_each_entry_safe(rg, trg, rg->link.prev, link) { |
| if (&rg->link == head) |
| break; |
| if (rg->from > t) |
| break; |
| |
| /* If this area reaches higher then extend our area to |
| * include it completely. If this is not the first area |
| * which we intend to reuse, free it. */ |
| if (rg->to > t) |
| t = rg->to; |
| if (rg != nrg) { |
| list_del(&rg->link); |
| kfree(rg); |
| } |
| } |
| nrg->from = f; |
| nrg->to = t; |
| return 0; |
| } |
| |
| static long region_chg(struct list_head *head, long f, long t) |
| { |
| struct file_region *rg, *nrg; |
| long chg = 0; |
| |
| /* Locate the region we are before or in. */ |
| list_for_each_entry(rg, head, link) |
| if (f <= rg->to) |
| break; |
| |
| /* If we are below the current region then a new region is required. |
| * Subtle, allocate a new region at the position but make it zero |
| * size such that we can guarantee to record the reservation. */ |
| if (&rg->link == head || t < rg->from) { |
| nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); |
| if (!nrg) |
| return -ENOMEM; |
| nrg->from = f; |
| nrg->to = f; |
| INIT_LIST_HEAD(&nrg->link); |
| list_add(&nrg->link, rg->link.prev); |
| |
| return t - f; |
| } |
| |
| /* Round our left edge to the current segment if it encloses us. */ |
| if (f > rg->from) |
| f = rg->from; |
| chg = t - f; |
| |
| /* Check for and consume any regions we now overlap with. */ |
| list_for_each_entry(rg, rg->link.prev, link) { |
| if (&rg->link == head) |
| break; |
| if (rg->from > t) |
| return chg; |
| |
| /* We overlap with this area, if it extends futher than |
| * us then we must extend ourselves. Account for its |
| * existing reservation. */ |
| if (rg->to > t) { |
| chg += rg->to - t; |
| t = rg->to; |
| } |
| chg -= rg->to - rg->from; |
| } |
| return chg; |
| } |
| |
| static long region_truncate(struct list_head *head, long end) |
| { |
| struct file_region *rg, *trg; |
| long chg = 0; |
| |
| /* Locate the region we are either in or before. */ |
| list_for_each_entry(rg, head, link) |
| if (end <= rg->to) |
| break; |
| if (&rg->link == head) |
| return 0; |
| |
| /* If we are in the middle of a region then adjust it. */ |
| if (end > rg->from) { |
| chg = rg->to - end; |
| rg->to = end; |
| rg = list_entry(rg->link.next, typeof(*rg), link); |
| } |
| |
| /* Drop any remaining regions. */ |
| list_for_each_entry_safe(rg, trg, rg->link.prev, link) { |
| if (&rg->link == head) |
| break; |
| chg += rg->to - rg->from; |
| list_del(&rg->link); |
| kfree(rg); |
| } |
| return chg; |
| } |
| |
| int hugetlb_reserve_pages(struct inode *inode, |
| long from, long to, |
| struct vm_area_struct *vma) |
| { |
| long ret, chg; |
| |
| /* |
| * Shared mappings base their reservation on the number of pages that |
| * are already allocated on behalf of the file. Private mappings need |
| * to reserve the full area even if read-only as mprotect() may be |
| * called to make the mapping read-write. Assume !vma is a shm mapping |
| */ |
| if (!vma || vma->vm_flags & VM_SHARED) |
| chg = region_chg(&inode->i_mapping->private_list, from, to); |
| else { |
| chg = to - from; |
| set_vma_resv_huge_pages(vma, chg); |
| set_vma_resv_flags(vma, HPAGE_RESV_OWNER); |
| } |
| |
| if (chg < 0) |
| return chg; |
| |
| if (hugetlb_get_quota(inode->i_mapping, chg)) |
| return -ENOSPC; |
| ret = hugetlb_acct_memory(chg); |
| if (ret < 0) { |
| hugetlb_put_quota(inode->i_mapping, chg); |
| return ret; |
| } |
| if (!vma || vma->vm_flags & VM_SHARED) |
| region_add(&inode->i_mapping->private_list, from, to); |
| return 0; |
| } |
| |
| void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) |
| { |
| long chg = region_truncate(&inode->i_mapping->private_list, offset); |
| |
| spin_lock(&inode->i_lock); |
| inode->i_blocks -= BLOCKS_PER_HUGEPAGE * freed; |
| spin_unlock(&inode->i_lock); |
| |
| hugetlb_put_quota(inode->i_mapping, (chg - freed)); |
| hugetlb_acct_memory(-(chg - freed)); |
| } |