diff options
Diffstat (limited to 'mm/hugetlb.c')
-rw-r--r-- | mm/hugetlb.c | 531 |
1 files changed, 367 insertions, 164 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index dbc949c409c7..aa55badf57f7 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -435,25 +435,6 @@ static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) return (get_vma_private_data(vma) & flag) != 0; } -/* Decrement the reserved pages in the hugepage pool by one */ -static void decrement_hugepage_resv_vma(struct hstate *h, - struct vm_area_struct *vma) -{ - if (vma->vm_flags & VM_NORESERVE) - return; - - if (vma->vm_flags & VM_MAYSHARE) { - /* Shared mappings always use reserves */ - h->resv_huge_pages--; - } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { - /* - * Only the process that called mmap() has reserves for - * private mappings. - */ - h->resv_huge_pages--; - } -} - /* Reset counters to 0 and clear all HPAGE_RESV_* flags */ void reset_vma_resv_huge_pages(struct vm_area_struct *vma) { @@ -463,12 +444,35 @@ void reset_vma_resv_huge_pages(struct vm_area_struct *vma) } /* Returns true if the VMA has associated reserve pages */ -static int vma_has_reserves(struct vm_area_struct *vma) +static int vma_has_reserves(struct vm_area_struct *vma, long chg) { + if (vma->vm_flags & VM_NORESERVE) { + /* + * This address is already reserved by other process(chg == 0), + * so, we should decrement reserved count. Without decrementing, + * reserve count remains after releasing inode, because this + * allocated page will go into page cache and is regarded as + * coming from reserved pool in releasing step. Currently, we + * don't have any other solution to deal with this situation + * properly, so add work-around here. + */ + if (vma->vm_flags & VM_MAYSHARE && chg == 0) + return 1; + else + return 0; + } + + /* Shared mappings always use reserves */ if (vma->vm_flags & VM_MAYSHARE) return 1; + + /* + * Only the process that called mmap() has reserves for + * private mappings. + */ if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) return 1; + return 0; } @@ -536,7 +540,8 @@ static struct page *dequeue_huge_page_node(struct hstate *h, int nid) static struct page *dequeue_huge_page_vma(struct hstate *h, struct vm_area_struct *vma, - unsigned long address, int avoid_reserve) + unsigned long address, int avoid_reserve, + long chg) { struct page *page = NULL; struct mempolicy *mpol; @@ -555,7 +560,7 @@ retry_cpuset: * have no page reserves. This check ensures that reservations are * not "stolen". The child may still get SIGKILLed */ - if (!vma_has_reserves(vma) && + if (!vma_has_reserves(vma, chg) && h->free_huge_pages - h->resv_huge_pages == 0) goto err; @@ -568,8 +573,13 @@ retry_cpuset: if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask)) { page = dequeue_huge_page_node(h, zone_to_nid(zone)); if (page) { - if (!avoid_reserve) - decrement_hugepage_resv_vma(h, vma); + if (avoid_reserve) + break; + if (!vma_has_reserves(vma, chg)) + break; + + SetPagePrivate(page); + h->resv_huge_pages--; break; } } @@ -627,15 +637,20 @@ static void free_huge_page(struct page *page) int nid = page_to_nid(page); struct hugepage_subpool *spool = (struct hugepage_subpool *)page_private(page); + bool restore_reserve; set_page_private(page, 0); page->mapping = NULL; BUG_ON(page_count(page)); BUG_ON(page_mapcount(page)); + restore_reserve = PagePrivate(page); spin_lock(&hugetlb_lock); hugetlb_cgroup_uncharge_page(hstate_index(h), pages_per_huge_page(h), page); + if (restore_reserve) + h->resv_huge_pages++; + if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { /* remove the page from active list */ list_del(&page->lru); @@ -796,33 +811,6 @@ static int hstate_next_node_to_alloc(struct hstate *h, return nid; } -static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) -{ - struct page *page; - int start_nid; - int next_nid; - int ret = 0; - - start_nid = hstate_next_node_to_alloc(h, nodes_allowed); - next_nid = start_nid; - - do { - page = alloc_fresh_huge_page_node(h, next_nid); - if (page) { - ret = 1; - break; - } - next_nid = hstate_next_node_to_alloc(h, nodes_allowed); - } while (next_nid != start_nid); - - if (ret) - count_vm_event(HTLB_BUDDY_PGALLOC); - else - count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); - - return ret; -} - /* * helper for free_pool_huge_page() - return the previously saved * node ["this node"] from which to free a huge page. Advance the @@ -841,6 +829,40 @@ static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) return nid; } +#define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \ + for (nr_nodes = nodes_weight(*mask); \ + nr_nodes > 0 && \ + ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \ + nr_nodes--) + +#define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \ + for (nr_nodes = nodes_weight(*mask); \ + nr_nodes > 0 && \ + ((node = hstate_next_node_to_free(hs, mask)) || 1); \ + nr_nodes--) + +static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) +{ + struct page *page; + int nr_nodes, node; + int ret = 0; + + for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { + page = alloc_fresh_huge_page_node(h, node); + if (page) { + ret = 1; + break; + } + } + + if (ret) + count_vm_event(HTLB_BUDDY_PGALLOC); + else + count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); + + return ret; +} + /* * Free huge page from pool from next node to free. * Attempt to keep persistent huge pages more or less @@ -850,36 +872,31 @@ static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, bool acct_surplus) { - int start_nid; - int next_nid; + int nr_nodes, node; int ret = 0; - start_nid = hstate_next_node_to_free(h, nodes_allowed); - next_nid = start_nid; - - do { + for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { /* * If we're returning unused surplus pages, only examine * nodes with surplus pages. */ - if ((!acct_surplus || h->surplus_huge_pages_node[next_nid]) && - !list_empty(&h->hugepage_freelists[next_nid])) { + if ((!acct_surplus || h->surplus_huge_pages_node[node]) && + !list_empty(&h->hugepage_freelists[node])) { struct page *page = - list_entry(h->hugepage_freelists[next_nid].next, + list_entry(h->hugepage_freelists[node].next, struct page, lru); list_del(&page->lru); h->free_huge_pages--; - h->free_huge_pages_node[next_nid]--; + h->free_huge_pages_node[node]--; if (acct_surplus) { h->surplus_huge_pages--; - h->surplus_huge_pages_node[next_nid]--; + h->surplus_huge_pages_node[node]--; } update_and_free_page(h, page); ret = 1; break; } - next_nid = hstate_next_node_to_free(h, nodes_allowed); - } while (next_nid != start_nid); + } return ret; } @@ -968,10 +985,11 @@ static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) */ struct page *alloc_huge_page_node(struct hstate *h, int nid) { - struct page *page; + struct page *page = NULL; spin_lock(&hugetlb_lock); - page = dequeue_huge_page_node(h, nid); + if (h->free_huge_pages - h->resv_huge_pages > 0) + page = dequeue_huge_page_node(h, nid); spin_unlock(&hugetlb_lock); if (!page) @@ -1059,11 +1077,8 @@ free: spin_unlock(&hugetlb_lock); /* Free unnecessary surplus pages to the buddy allocator */ - if (!list_empty(&surplus_list)) { - list_for_each_entry_safe(page, tmp, &surplus_list, lru) { - put_page(page); - } - } + list_for_each_entry_safe(page, tmp, &surplus_list, lru) + put_page(page); spin_lock(&hugetlb_lock); return ret; @@ -1131,9 +1146,9 @@ static long vma_needs_reservation(struct hstate *h, } else { long err; pgoff_t idx = vma_hugecache_offset(h, vma, addr); - struct resv_map *reservations = vma_resv_map(vma); + struct resv_map *resv = vma_resv_map(vma); - err = region_chg(&reservations->regions, idx, idx + 1); + err = region_chg(&resv->regions, idx, idx + 1); if (err < 0) return err; return 0; @@ -1151,10 +1166,10 @@ static void vma_commit_reservation(struct hstate *h, } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { pgoff_t idx = vma_hugecache_offset(h, vma, addr); - struct resv_map *reservations = vma_resv_map(vma); + struct resv_map *resv = vma_resv_map(vma); /* Mark this page used in the map. */ - region_add(&reservations->regions, idx, idx + 1); + region_add(&resv->regions, idx, idx + 1); } } @@ -1180,38 +1195,35 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, chg = vma_needs_reservation(h, vma, addr); if (chg < 0) return ERR_PTR(-ENOMEM); - if (chg) - if (hugepage_subpool_get_pages(spool, chg)) + if (chg || avoid_reserve) + if (hugepage_subpool_get_pages(spool, 1)) return ERR_PTR(-ENOSPC); ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); if (ret) { - hugepage_subpool_put_pages(spool, chg); + if (chg || avoid_reserve) + hugepage_subpool_put_pages(spool, 1); return ERR_PTR(-ENOSPC); } spin_lock(&hugetlb_lock); - page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve); - if (page) { - /* update page cgroup details */ - hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), - h_cg, page); - spin_unlock(&hugetlb_lock); - } else { + page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, chg); + if (!page) { spin_unlock(&hugetlb_lock); page = alloc_buddy_huge_page(h, NUMA_NO_NODE); if (!page) { hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg); - hugepage_subpool_put_pages(spool, chg); + if (chg || avoid_reserve) + hugepage_subpool_put_pages(spool, 1); return ERR_PTR(-ENOSPC); } spin_lock(&hugetlb_lock); - hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), - h_cg, page); list_move(&page->lru, &h->hugepage_activelist); - spin_unlock(&hugetlb_lock); + /* Fall through */ } + hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page); + spin_unlock(&hugetlb_lock); set_page_private(page, (unsigned long)spool); @@ -1222,14 +1234,12 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, int __weak alloc_bootmem_huge_page(struct hstate *h) { struct huge_bootmem_page *m; - int nr_nodes = nodes_weight(node_states[N_MEMORY]); + int nr_nodes, node; - while (nr_nodes) { + for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) { void *addr; - addr = __alloc_bootmem_node_nopanic( - NODE_DATA(hstate_next_node_to_alloc(h, - &node_states[N_MEMORY])), + addr = __alloc_bootmem_node_nopanic(NODE_DATA(node), huge_page_size(h), huge_page_size(h), 0); if (addr) { @@ -1241,7 +1251,6 @@ int __weak alloc_bootmem_huge_page(struct hstate *h) m = addr; goto found; } - nr_nodes--; } return 0; @@ -1380,48 +1389,28 @@ static inline void try_to_free_low(struct hstate *h, unsigned long count, static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, int delta) { - int start_nid, next_nid; - int ret = 0; + int nr_nodes, node; VM_BUG_ON(delta != -1 && delta != 1); - if (delta < 0) - start_nid = hstate_next_node_to_alloc(h, nodes_allowed); - else - start_nid = hstate_next_node_to_free(h, nodes_allowed); - next_nid = start_nid; - - do { - int nid = next_nid; - if (delta < 0) { - /* - * To shrink on this node, there must be a surplus page - */ - if (!h->surplus_huge_pages_node[nid]) { - next_nid = hstate_next_node_to_alloc(h, - nodes_allowed); - continue; - } + if (delta < 0) { + for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { + if (h->surplus_huge_pages_node[node]) + goto found; } - if (delta > 0) { - /* - * Surplus cannot exceed the total number of pages - */ - if (h->surplus_huge_pages_node[nid] >= - h->nr_huge_pages_node[nid]) { - next_nid = hstate_next_node_to_free(h, - nodes_allowed); - continue; - } + } else { + for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { + if (h->surplus_huge_pages_node[node] < + h->nr_huge_pages_node[node]) + goto found; } + } + return 0; - h->surplus_huge_pages += delta; - h->surplus_huge_pages_node[nid] += delta; - ret = 1; - break; - } while (next_nid != start_nid); - - return ret; +found: + h->surplus_huge_pages += delta; + h->surplus_huge_pages_node[node] += delta; + return 1; } #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) @@ -2233,7 +2222,7 @@ out: static void hugetlb_vm_op_open(struct vm_area_struct *vma) { - struct resv_map *reservations = vma_resv_map(vma); + struct resv_map *resv = vma_resv_map(vma); /* * This new VMA should share its siblings reservation map if present. @@ -2243,34 +2232,34 @@ static void hugetlb_vm_op_open(struct vm_area_struct *vma) * after this open call completes. It is therefore safe to take a * new reference here without additional locking. */ - if (reservations) - kref_get(&reservations->refs); + if (resv) + kref_get(&resv->refs); } static void resv_map_put(struct vm_area_struct *vma) { - struct resv_map *reservations = vma_resv_map(vma); + struct resv_map *resv = vma_resv_map(vma); - if (!reservations) + if (!resv) return; - kref_put(&reservations->refs, resv_map_release); + kref_put(&resv->refs, resv_map_release); } static void hugetlb_vm_op_close(struct vm_area_struct *vma) { struct hstate *h = hstate_vma(vma); - struct resv_map *reservations = vma_resv_map(vma); + struct resv_map *resv = vma_resv_map(vma); struct hugepage_subpool *spool = subpool_vma(vma); unsigned long reserve; unsigned long start; unsigned long end; - if (reservations) { + if (resv) { start = vma_hugecache_offset(h, vma, vma->vm_start); end = vma_hugecache_offset(h, vma, vma->vm_end); reserve = (end - start) - - region_count(&reservations->regions, start, end); + region_count(&resv->regions, start, end); resv_map_put(vma); @@ -2363,16 +2352,26 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, int cow; struct hstate *h = hstate_vma(vma); unsigned long sz = huge_page_size(h); + unsigned long mmun_start; /* For mmu_notifiers */ + unsigned long mmun_end; /* For mmu_notifiers */ + int ret = 0; cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; + mmun_start = vma->vm_start; + mmun_end = vma->vm_end; + if (cow) + mmu_notifier_invalidate_range_start(src, mmun_start, mmun_end); + for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { src_pte = huge_pte_offset(src, addr); if (!src_pte) continue; dst_pte = huge_pte_alloc(dst, addr, sz); - if (!dst_pte) - goto nomem; + if (!dst_pte) { + ret = -ENOMEM; + break; + } /* If the pagetables are shared don't copy or take references */ if (dst_pte == src_pte) @@ -2408,10 +2407,11 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, spin_unlock(&src->page_table_lock); spin_unlock(&dst->page_table_lock); } - return 0; -nomem: - return -ENOMEM; + if (cow) + mmu_notifier_invalidate_range_end(src, mmun_start, mmun_end); + + return ret; } void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, @@ -2598,7 +2598,6 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, { struct hstate *h = hstate_vma(vma); struct page *old_page, *new_page; - int avoidcopy; int outside_reserve = 0; unsigned long mmun_start; /* For mmu_notifiers */ unsigned long mmun_end; /* For mmu_notifiers */ @@ -2608,10 +2607,8 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, retry_avoidcopy: /* If no-one else is actually using this page, avoid the copy * and just make the page writable */ - avoidcopy = (page_mapcount(old_page) == 1); - if (avoidcopy) { - if (PageAnon(old_page)) - page_move_anon_rmap(old_page, vma, address); + if (page_mapcount(old_page) == 1 && PageAnon(old_page)) { + page_move_anon_rmap(old_page, vma, address); set_huge_ptep_writable(vma, address, ptep); return 0; } @@ -2625,8 +2622,7 @@ retry_avoidcopy: * at the time of fork() could consume its reserves on COW instead * of the full address range. */ - if (!(vma->vm_flags & VM_MAYSHARE) && - is_vma_resv_set(vma, HPAGE_RESV_OWNER) && + if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && old_page != pagecache_page) outside_reserve = 1; @@ -2698,6 +2694,8 @@ retry_avoidcopy: spin_lock(&mm->page_table_lock); ptep = huge_pte_offset(mm, address & huge_page_mask(h)); if (likely(pte_same(huge_ptep_get(ptep), pte))) { + ClearPagePrivate(new_page); + /* Break COW */ huge_ptep_clear_flush(vma, address, ptep); set_huge_pte_at(mm, address, ptep, @@ -2709,10 +2707,11 @@ retry_avoidcopy: } spin_unlock(&mm->page_table_lock); mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); - /* Caller expects lock to be held */ - spin_lock(&mm->page_table_lock); page_cache_release(new_page); page_cache_release(old_page); + + /* Caller expects lock to be held */ + spin_lock(&mm->page_table_lock); return 0; } @@ -2808,6 +2807,7 @@ retry: goto retry; goto out; } + ClearPagePrivate(page); spin_lock(&inode->i_lock); inode->i_blocks += blocks_per_huge_page(h); @@ -2854,8 +2854,10 @@ retry: if (!huge_pte_none(huge_ptep_get(ptep))) goto backout; - if (anon_rmap) + if (anon_rmap) { + ClearPagePrivate(page); hugepage_add_new_anon_rmap(page, vma, address); + } else page_dup_rmap(page); new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) @@ -2989,15 +2991,6 @@ out_mutex: return ret; } -/* Can be overriden by architectures */ -__attribute__((weak)) struct page * -follow_huge_pud(struct mm_struct *mm, unsigned long address, - pud_t *pud, int write) -{ - BUG(); - return NULL; -} - long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, struct page **pages, struct vm_area_struct **vmas, unsigned long *position, unsigned long *nr_pages, @@ -3227,6 +3220,216 @@ void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) hugetlb_acct_memory(h, -(chg - freed)); } +#ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE +static unsigned long page_table_shareable(struct vm_area_struct *svma, + struct vm_area_struct *vma, + unsigned long addr, pgoff_t idx) +{ + unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) + + svma->vm_start; + unsigned long sbase = saddr & PUD_MASK; + unsigned long s_end = sbase + PUD_SIZE; + + /* Allow segments to share if only one is marked locked */ + unsigned long vm_flags = vma->vm_flags & ~VM_LOCKED; + unsigned long svm_flags = svma->vm_flags & ~VM_LOCKED; + + /* + * match the virtual addresses, permission and the alignment of the + * page table page. + */ + if (pmd_index(addr) != pmd_index(saddr) || + vm_flags != svm_flags || + sbase < svma->vm_start || svma->vm_end < s_end) + return 0; + + return saddr; +} + +static int vma_shareable(struct vm_area_struct *vma, unsigned long addr) +{ + unsigned long base = addr & PUD_MASK; + unsigned long end = base + PUD_SIZE; + + /* + * check on proper vm_flags and page table alignment + */ + if (vma->vm_flags & VM_MAYSHARE && + vma->vm_start <= base && end <= vma->vm_end) + return 1; + return 0; +} + +/* + * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc() + * and returns the corresponding pte. While this is not necessary for the + * !shared pmd case because we can allocate the pmd later as well, it makes the + * code much cleaner. pmd allocation is essential for the shared case because + * pud has to be populated inside the same i_mmap_mutex section - otherwise + * racing tasks could either miss the sharing (see huge_pte_offset) or select a + * bad pmd for sharing. + */ +pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) +{ + struct vm_area_struct *vma = find_vma(mm, addr); + struct address_space *mapping = vma->vm_file->f_mapping; + pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + + vma->vm_pgoff; + struct vm_area_struct *svma; + unsigned long saddr; + pte_t *spte = NULL; + pte_t *pte; + + if (!vma_shareable(vma, addr)) + return (pte_t *)pmd_alloc(mm, pud, addr); + + mutex_lock(&mapping->i_mmap_mutex); + vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) { + if (svma == vma) + continue; + + saddr = page_table_shareable(svma, vma, addr, idx); + if (saddr) { + spte = huge_pte_offset(svma->vm_mm, saddr); + if (spte) { + get_page(virt_to_page(spte)); + break; + } + } + } + + if (!spte) + goto out; + + spin_lock(&mm->page_table_lock); + if (pud_none(*pud)) + pud_populate(mm, pud, + (pmd_t *)((unsigned long)spte & PAGE_MASK)); + else + put_page(virt_to_page(spte)); + spin_unlock(&mm->page_table_lock); +out: + pte = (pte_t *)pmd_alloc(mm, pud, addr); + mutex_unlock(&mapping->i_mmap_mutex); + return pte; +} + +/* + * unmap huge page backed by shared pte. + * + * Hugetlb pte page is ref counted at the time of mapping. If pte is shared + * indicated by page_count > 1, unmap is achieved by clearing pud and + * decrementing the ref count. If count == 1, the pte page is not shared. + * + * called with vma->vm_mm->page_table_lock held. + * + * returns: 1 successfully unmapped a shared pte page + * 0 the underlying pte page is not shared, or it is the last user + */ +int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) +{ + pgd_t *pgd = pgd_offset(mm, *addr); + pud_t *pud = pud_offset(pgd, *addr); + + BUG_ON(page_count(virt_to_page(ptep)) == 0); + if (page_count(virt_to_page(ptep)) == 1) + return 0; + + pud_clear(pud); + put_page(virt_to_page(ptep)); + *addr = ALIGN(*addr, HPAGE_SIZE * PTRS_PER_PTE) - HPAGE_SIZE; + return 1; +} +#define want_pmd_share() (1) +#else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ +pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud) +{ + return NULL; +} +#define want_pmd_share() (0) +#endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ + +#ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB +pte_t *huge_pte_alloc(struct mm_struct *mm, + unsigned long addr, unsigned long sz) +{ + pgd_t *pgd; + pud_t *pud; + pte_t *pte = NULL; + + pgd = pgd_offset(mm, addr); + pud = pud_alloc(mm, pgd, addr); + if (pud) { + if (sz == PUD_SIZE) { + pte = (pte_t *)pud; + } else { + BUG_ON(sz != PMD_SIZE); + if (want_pmd_share() && pud_none(*pud)) + pte = huge_pmd_share(mm, addr, pud); + else + pte = (pte_t *)pmd_alloc(mm, pud, addr); + } + } + BUG_ON(pte && !pte_none(*pte) && !pte_huge(*pte)); + + return pte; +} + +pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd = NULL; + + pgd = pgd_offset(mm, addr); + if (pgd_present(*pgd)) { + pud = pud_offset(pgd, addr); + if (pud_present(*pud)) { + if (pud_huge(*pud)) + return (pte_t *)pud; + pmd = pmd_offset(pud, addr); + } + } + return (pte_t *) pmd; +} + +struct page * +follow_huge_pmd(struct mm_struct *mm, unsigned long address, + pmd_t *pmd, int write) +{ + struct page *page; + + page = pte_page(*(pte_t *)pmd); + if (page) + page += ((address & ~PMD_MASK) >> PAGE_SHIFT); + return page; +} + +struct page * +follow_huge_pud(struct mm_struct *mm, unsigned long address, + pud_t *pud, int write) +{ + struct page *page; + + page = pte_page(*(pte_t *)pud); + if (page) + page += ((address & ~PUD_MASK) >> PAGE_SHIFT); + return page; +} + +#else /* !CONFIG_ARCH_WANT_GENERAL_HUGETLB */ + +/* Can be overriden by architectures */ +__attribute__((weak)) struct page * +follow_huge_pud(struct mm_struct *mm, unsigned long address, + pud_t *pud, int write) +{ + BUG(); + return NULL; +} + +#endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ + #ifdef CONFIG_MEMORY_FAILURE /* Should be called in hugetlb_lock */ |