diff options
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 562 |
1 files changed, 355 insertions, 207 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index c82290b9c1f..eeceeeb0901 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -35,7 +35,6 @@ #include <linux/node.h> #include "internal.h" -const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; unsigned long hugepages_treat_as_movable; int hugetlb_max_hstate __read_mostly; @@ -544,7 +543,7 @@ static struct page *dequeue_huge_page_node(struct hstate *h, int nid) /* Movability of hugepages depends on migration support. */ static inline gfp_t htlb_alloc_mask(struct hstate *h) { - if (hugepages_treat_as_movable || hugepage_migration_support(h)) + if (hugepages_treat_as_movable || hugepage_migration_supported(h)) return GFP_HIGHUSER_MOVABLE; else return GFP_HIGHUSER; @@ -607,25 +606,242 @@ err: return NULL; } +/* + * common helper functions for hstate_next_node_to_{alloc|free}. + * We may have allocated or freed a huge page based on a different + * nodes_allowed previously, so h->next_node_to_{alloc|free} might + * be outside of *nodes_allowed. Ensure that we use an allowed + * node for alloc or free. + */ +static int next_node_allowed(int nid, nodemask_t *nodes_allowed) +{ + nid = next_node(nid, *nodes_allowed); + if (nid == MAX_NUMNODES) + nid = first_node(*nodes_allowed); + VM_BUG_ON(nid >= MAX_NUMNODES); + + return nid; +} + +static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) +{ + if (!node_isset(nid, *nodes_allowed)) + nid = next_node_allowed(nid, nodes_allowed); + return nid; +} + +/* + * returns the previously saved node ["this node"] from which to + * allocate a persistent huge page for the pool and advance the + * next node from which to allocate, handling wrap at end of node + * mask. + */ +static int hstate_next_node_to_alloc(struct hstate *h, + nodemask_t *nodes_allowed) +{ + int nid; + + VM_BUG_ON(!nodes_allowed); + + nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); + h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); + + return nid; +} + +/* + * helper for free_pool_huge_page() - return the previously saved + * node ["this node"] from which to free a huge page. Advance the + * next node id whether or not we find a free huge page to free so + * that the next attempt to free addresses the next node. + */ +static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) +{ + int nid; + + VM_BUG_ON(!nodes_allowed); + + nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); + h->next_nid_to_free = next_node_allowed(nid, 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--) + +#if defined(CONFIG_CMA) && defined(CONFIG_X86_64) +static void destroy_compound_gigantic_page(struct page *page, + unsigned long order) +{ + int i; + int nr_pages = 1 << order; + struct page *p = page + 1; + + for (i = 1; i < nr_pages; i++, p = mem_map_next(p, page, i)) { + __ClearPageTail(p); + set_page_refcounted(p); + p->first_page = NULL; + } + + set_compound_order(page, 0); + __ClearPageHead(page); +} + +static void free_gigantic_page(struct page *page, unsigned order) +{ + free_contig_range(page_to_pfn(page), 1 << order); +} + +static int __alloc_gigantic_page(unsigned long start_pfn, + unsigned long nr_pages) +{ + unsigned long end_pfn = start_pfn + nr_pages; + return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE); +} + +static bool pfn_range_valid_gigantic(unsigned long start_pfn, + unsigned long nr_pages) +{ + unsigned long i, end_pfn = start_pfn + nr_pages; + struct page *page; + + for (i = start_pfn; i < end_pfn; i++) { + if (!pfn_valid(i)) + return false; + + page = pfn_to_page(i); + + if (PageReserved(page)) + return false; + + if (page_count(page) > 0) + return false; + + if (PageHuge(page)) + return false; + } + + return true; +} + +static bool zone_spans_last_pfn(const struct zone *zone, + unsigned long start_pfn, unsigned long nr_pages) +{ + unsigned long last_pfn = start_pfn + nr_pages - 1; + return zone_spans_pfn(zone, last_pfn); +} + +static struct page *alloc_gigantic_page(int nid, unsigned order) +{ + unsigned long nr_pages = 1 << order; + unsigned long ret, pfn, flags; + struct zone *z; + + z = NODE_DATA(nid)->node_zones; + for (; z - NODE_DATA(nid)->node_zones < MAX_NR_ZONES; z++) { + spin_lock_irqsave(&z->lock, flags); + + pfn = ALIGN(z->zone_start_pfn, nr_pages); + while (zone_spans_last_pfn(z, pfn, nr_pages)) { + if (pfn_range_valid_gigantic(pfn, nr_pages)) { + /* + * We release the zone lock here because + * alloc_contig_range() will also lock the zone + * at some point. If there's an allocation + * spinning on this lock, it may win the race + * and cause alloc_contig_range() to fail... + */ + spin_unlock_irqrestore(&z->lock, flags); + ret = __alloc_gigantic_page(pfn, nr_pages); + if (!ret) + return pfn_to_page(pfn); + spin_lock_irqsave(&z->lock, flags); + } + pfn += nr_pages; + } + + spin_unlock_irqrestore(&z->lock, flags); + } + + return NULL; +} + +static void prep_new_huge_page(struct hstate *h, struct page *page, int nid); +static void prep_compound_gigantic_page(struct page *page, unsigned long order); + +static struct page *alloc_fresh_gigantic_page_node(struct hstate *h, int nid) +{ + struct page *page; + + page = alloc_gigantic_page(nid, huge_page_order(h)); + if (page) { + prep_compound_gigantic_page(page, huge_page_order(h)); + prep_new_huge_page(h, page, nid); + } + + return page; +} + +static int alloc_fresh_gigantic_page(struct hstate *h, + nodemask_t *nodes_allowed) +{ + struct page *page = NULL; + int nr_nodes, node; + + for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { + page = alloc_fresh_gigantic_page_node(h, node); + if (page) + return 1; + } + + return 0; +} + +static inline bool gigantic_page_supported(void) { return true; } +#else +static inline bool gigantic_page_supported(void) { return false; } +static inline void free_gigantic_page(struct page *page, unsigned order) { } +static inline void destroy_compound_gigantic_page(struct page *page, + unsigned long order) { } +static inline int alloc_fresh_gigantic_page(struct hstate *h, + nodemask_t *nodes_allowed) { return 0; } +#endif + static void update_and_free_page(struct hstate *h, struct page *page) { int i; - VM_BUG_ON(h->order >= MAX_ORDER); + if (hstate_is_gigantic(h) && !gigantic_page_supported()) + return; h->nr_huge_pages--; h->nr_huge_pages_node[page_to_nid(page)]--; for (i = 0; i < pages_per_huge_page(h); 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); + 1 << PG_active | 1 << PG_private | + 1 << PG_writeback); } VM_BUG_ON_PAGE(hugetlb_cgroup_from_page(page), page); set_compound_page_dtor(page, NULL); set_page_refcounted(page); - arch_release_hugepage(page); - __free_pages(page, huge_page_order(h)); + if (hstate_is_gigantic(h)) { + destroy_compound_gigantic_page(page, huge_page_order(h)); + free_gigantic_page(page, huge_page_order(h)); + } else { + arch_release_hugepage(page); + __free_pages(page, huge_page_order(h)); + } } struct hstate *size_to_hstate(unsigned long size) @@ -639,7 +855,7 @@ struct hstate *size_to_hstate(unsigned long size) return NULL; } -static void free_huge_page(struct page *page) +void free_huge_page(struct page *page) { /* * Can't pass hstate in here because it is called from the @@ -664,7 +880,7 @@ static void free_huge_page(struct page *page) if (restore_reserve) h->resv_huge_pages++; - if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) { + if (h->surplus_huge_pages_node[nid]) { /* remove the page from active list */ list_del(&page->lru); update_and_free_page(h, page); @@ -690,8 +906,7 @@ static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) put_page(page); /* free it into the hugepage allocator */ } -static void __init prep_compound_gigantic_page(struct page *page, - unsigned long order) +static void prep_compound_gigantic_page(struct page *page, unsigned long order) { int i; int nr_pages = 1 << order; @@ -769,9 +984,6 @@ static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) { struct page *page; - if (h->order >= MAX_ORDER) - return NULL; - page = alloc_pages_exact_node(nid, htlb_alloc_mask(h)|__GFP_COMP|__GFP_THISNODE| __GFP_REPEAT|__GFP_NOWARN, @@ -787,79 +999,6 @@ static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) return page; } -/* - * common helper functions for hstate_next_node_to_{alloc|free}. - * We may have allocated or freed a huge page based on a different - * nodes_allowed previously, so h->next_node_to_{alloc|free} might - * be outside of *nodes_allowed. Ensure that we use an allowed - * node for alloc or free. - */ -static int next_node_allowed(int nid, nodemask_t *nodes_allowed) -{ - nid = next_node(nid, *nodes_allowed); - if (nid == MAX_NUMNODES) - nid = first_node(*nodes_allowed); - VM_BUG_ON(nid >= MAX_NUMNODES); - - return nid; -} - -static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) -{ - if (!node_isset(nid, *nodes_allowed)) - nid = next_node_allowed(nid, nodes_allowed); - return nid; -} - -/* - * returns the previously saved node ["this node"] from which to - * allocate a persistent huge page for the pool and advance the - * next node from which to allocate, handling wrap at end of node - * mask. - */ -static int hstate_next_node_to_alloc(struct hstate *h, - nodemask_t *nodes_allowed) -{ - int nid; - - VM_BUG_ON(!nodes_allowed); - - nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); - h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); - - return nid; -} - -/* - * helper for free_pool_huge_page() - return the previously saved - * node ["this node"] from which to free a huge page. Advance the - * next node id whether or not we find a free huge page to free so - * that the next attempt to free addresses the next node. - */ -static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) -{ - int nid; - - VM_BUG_ON(!nodes_allowed); - - nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); - h->next_nid_to_free = next_node_allowed(nid, 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; @@ -949,6 +1088,9 @@ void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) unsigned long pfn; struct hstate *h; + if (!hugepages_supported()) + return; + /* Set scan step to minimum hugepage size */ for_each_hstate(h) if (order > huge_page_order(h)) @@ -963,7 +1105,7 @@ static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) struct page *page; unsigned int r_nid; - if (h->order >= MAX_ORDER) + if (hstate_is_gigantic(h)) return NULL; /* @@ -1156,7 +1298,7 @@ static void return_unused_surplus_pages(struct hstate *h, h->resv_huge_pages -= unused_resv_pages; /* Cannot return gigantic pages currently */ - if (h->order >= MAX_ORDER) + if (hstate_is_gigantic(h)) return; nr_pages = min(unused_resv_pages, h->surplus_huge_pages); @@ -1246,24 +1388,17 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, return ERR_PTR(-ENOSPC); ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); - if (ret) { - if (chg || avoid_reserve) - hugepage_subpool_put_pages(spool, 1); - return ERR_PTR(-ENOSPC); - } + if (ret) + goto out_subpool_put; + spin_lock(&hugetlb_lock); 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); - if (chg || avoid_reserve) - hugepage_subpool_put_pages(spool, 1); - return ERR_PTR(-ENOSPC); - } + if (!page) + goto out_uncharge_cgroup; + spin_lock(&hugetlb_lock); list_move(&page->lru, &h->hugepage_activelist); /* Fall through */ @@ -1275,6 +1410,13 @@ static struct page *alloc_huge_page(struct vm_area_struct *vma, vma_commit_reservation(h, vma, addr); return page; + +out_uncharge_cgroup: + hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg); +out_subpool_put: + if (chg || avoid_reserve) + hugepage_subpool_put_pages(spool, 1); + return ERR_PTR(-ENOSPC); } /* @@ -1356,7 +1498,7 @@ static void __init gather_bootmem_prealloc(void) * fix confusing memory reports from free(1) and another * side-effects, like CommitLimit going negative. */ - if (h->order > (MAX_ORDER - 1)) + if (hstate_is_gigantic(h)) adjust_managed_page_count(page, 1 << h->order); } } @@ -1366,7 +1508,7 @@ static void __init hugetlb_hstate_alloc_pages(struct hstate *h) unsigned long i; for (i = 0; i < h->max_huge_pages; ++i) { - if (h->order >= MAX_ORDER) { + if (hstate_is_gigantic(h)) { if (!alloc_bootmem_huge_page(h)) break; } else if (!alloc_fresh_huge_page(h, @@ -1382,7 +1524,7 @@ static void __init hugetlb_init_hstates(void) for_each_hstate(h) { /* oversize hugepages were init'ed in early boot */ - if (h->order < MAX_ORDER) + if (!hstate_is_gigantic(h)) hugetlb_hstate_alloc_pages(h); } } @@ -1416,7 +1558,7 @@ static void try_to_free_low(struct hstate *h, unsigned long count, { int i; - if (h->order >= MAX_ORDER) + if (hstate_is_gigantic(h)) return; for_each_node_mask(i, *nodes_allowed) { @@ -1479,7 +1621,7 @@ static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, { unsigned long min_count, ret; - if (h->order >= MAX_ORDER) + if (hstate_is_gigantic(h) && !gigantic_page_supported()) return h->max_huge_pages; /* @@ -1506,7 +1648,10 @@ static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, * and reducing the surplus. */ spin_unlock(&hugetlb_lock); - ret = alloc_fresh_huge_page(h, nodes_allowed); + if (hstate_is_gigantic(h)) + ret = alloc_fresh_gigantic_page(h, nodes_allowed); + else + ret = alloc_fresh_huge_page(h, nodes_allowed); spin_lock(&hugetlb_lock); if (!ret) goto out; @@ -1591,22 +1736,14 @@ static ssize_t nr_hugepages_show_common(struct kobject *kobj, return sprintf(buf, "%lu\n", nr_huge_pages); } -static ssize_t nr_hugepages_store_common(bool obey_mempolicy, - struct kobject *kobj, struct kobj_attribute *attr, - const char *buf, size_t len) +static ssize_t __nr_hugepages_store_common(bool obey_mempolicy, + struct hstate *h, int nid, + unsigned long count, size_t len) { int err; - int nid; - unsigned long count; - struct hstate *h; NODEMASK_ALLOC(nodemask_t, nodes_allowed, GFP_KERNEL | __GFP_NORETRY); - err = kstrtoul(buf, 10, &count); - if (err) - goto out; - - h = kobj_to_hstate(kobj, &nid); - if (h->order >= MAX_ORDER) { + if (hstate_is_gigantic(h) && !gigantic_page_supported()) { err = -EINVAL; goto out; } @@ -1641,6 +1778,23 @@ out: return err; } +static ssize_t nr_hugepages_store_common(bool obey_mempolicy, + struct kobject *kobj, const char *buf, + size_t len) +{ + struct hstate *h; + unsigned long count; + int nid; + int err; + + err = kstrtoul(buf, 10, &count); + if (err) + return err; + + h = kobj_to_hstate(kobj, &nid); + return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len); +} + static ssize_t nr_hugepages_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { @@ -1650,7 +1804,7 @@ static ssize_t nr_hugepages_show(struct kobject *kobj, static ssize_t nr_hugepages_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t len) { - return nr_hugepages_store_common(false, kobj, attr, buf, len); + return nr_hugepages_store_common(false, kobj, buf, len); } HSTATE_ATTR(nr_hugepages); @@ -1669,7 +1823,7 @@ static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t len) { - return nr_hugepages_store_common(true, kobj, attr, buf, len); + return nr_hugepages_store_common(true, kobj, buf, len); } HSTATE_ATTR(nr_hugepages_mempolicy); #endif @@ -1689,7 +1843,7 @@ static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, unsigned long input; struct hstate *h = kobj_to_hstate(kobj, NULL); - if (h->order >= MAX_ORDER) + if (hstate_is_gigantic(h)) return -EINVAL; err = kstrtoul(buf, 10, &input); @@ -2105,36 +2259,21 @@ static int hugetlb_sysctl_handler_common(bool obey_mempolicy, void __user *buffer, size_t *length, loff_t *ppos) { struct hstate *h = &default_hstate; - unsigned long tmp; + unsigned long tmp = h->max_huge_pages; int ret; if (!hugepages_supported()) return -ENOTSUPP; - tmp = h->max_huge_pages; - - if (write && h->order >= MAX_ORDER) - return -EINVAL; - table->data = &tmp; table->maxlen = sizeof(unsigned long); ret = proc_doulongvec_minmax(table, write, buffer, length, ppos); if (ret) goto out; - if (write) { - NODEMASK_ALLOC(nodemask_t, nodes_allowed, - GFP_KERNEL | __GFP_NORETRY); - if (!(obey_mempolicy && - init_nodemask_of_mempolicy(nodes_allowed))) { - NODEMASK_FREE(nodes_allowed); - nodes_allowed = &node_states[N_MEMORY]; - } - h->max_huge_pages = set_max_huge_pages(h, tmp, nodes_allowed); - - if (nodes_allowed != &node_states[N_MEMORY]) - NODEMASK_FREE(nodes_allowed); - } + if (write) + ret = __nr_hugepages_store_common(obey_mempolicy, h, + NUMA_NO_NODE, tmp, *length); out: return ret; } @@ -2169,7 +2308,7 @@ int hugetlb_overcommit_handler(struct ctl_table *table, int write, tmp = h->nr_overcommit_huge_pages; - if (write && h->order >= MAX_ORDER) + if (write && hstate_is_gigantic(h)) return -EINVAL; table->data = &tmp; @@ -2377,6 +2516,31 @@ static void set_huge_ptep_writable(struct vm_area_struct *vma, update_mmu_cache(vma, address, ptep); } +static int is_hugetlb_entry_migration(pte_t pte) +{ + swp_entry_t swp; + + if (huge_pte_none(pte) || pte_present(pte)) + return 0; + swp = pte_to_swp_entry(pte); + if (non_swap_entry(swp) && is_migration_entry(swp)) + return 1; + else + return 0; +} + +static int is_hugetlb_entry_hwpoisoned(pte_t pte) +{ + swp_entry_t swp; + + if (huge_pte_none(pte) || pte_present(pte)) + return 0; + swp = pte_to_swp_entry(pte); + if (non_swap_entry(swp) && is_hwpoison_entry(swp)) + return 1; + else + return 0; +} int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, struct vm_area_struct *vma) @@ -2416,7 +2580,24 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, dst_ptl = huge_pte_lock(h, dst, dst_pte); src_ptl = huge_pte_lockptr(h, src, src_pte); spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); - if (!huge_pte_none(huge_ptep_get(src_pte))) { + entry = huge_ptep_get(src_pte); + if (huge_pte_none(entry)) { /* skip none entry */ + ; + } else if (unlikely(is_hugetlb_entry_migration(entry) || + is_hugetlb_entry_hwpoisoned(entry))) { + swp_entry_t swp_entry = pte_to_swp_entry(entry); + + if (is_write_migration_entry(swp_entry) && cow) { + /* + * COW mappings require pages in both + * parent and child to be set to read. + */ + make_migration_entry_read(&swp_entry); + entry = swp_entry_to_pte(swp_entry); + set_huge_pte_at(src, addr, src_pte, entry); + } + set_huge_pte_at(dst, addr, dst_pte, entry); + } else { if (cow) huge_ptep_set_wrprotect(src, addr, src_pte); entry = huge_ptep_get(src_pte); @@ -2435,32 +2616,6 @@ int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, return ret; } -static int is_hugetlb_entry_migration(pte_t pte) -{ - swp_entry_t swp; - - if (huge_pte_none(pte) || pte_present(pte)) - return 0; - swp = pte_to_swp_entry(pte); - if (non_swap_entry(swp) && is_migration_entry(swp)) - return 1; - else - return 0; -} - -static int is_hugetlb_entry_hwpoisoned(pte_t pte) -{ - swp_entry_t swp; - - if (huge_pte_none(pte) || pte_present(pte)) - return 0; - swp = pte_to_swp_entry(pte); - if (non_swap_entry(swp) && is_hwpoison_entry(swp)) - return 1; - else - return 0; -} - void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, unsigned long start, unsigned long end, struct page *ref_page) @@ -2595,8 +2750,8 @@ void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, * from other VMAs and let the children be SIGKILLed if they are faulting the * same region. */ -static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, - struct page *page, unsigned long address) +static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, + struct page *page, unsigned long address) { struct hstate *h = hstate_vma(vma); struct vm_area_struct *iter_vma; @@ -2635,8 +2790,6 @@ static int unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, address + huge_page_size(h), page); } mutex_unlock(&mapping->i_mmap_mutex); - - return 1; } /* @@ -2651,7 +2804,7 @@ 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 outside_reserve = 0; + int ret = 0, outside_reserve = 0; unsigned long mmun_start; /* For mmu_notifiers */ unsigned long mmun_end; /* For mmu_notifiers */ @@ -2681,14 +2834,14 @@ retry_avoidcopy: page_cache_get(old_page); - /* Drop page table lock as buddy allocator may be called */ + /* + * Drop page table lock as buddy allocator may be called. It will + * be acquired again before returning to the caller, as expected. + */ spin_unlock(ptl); new_page = alloc_huge_page(vma, address, outside_reserve); if (IS_ERR(new_page)) { - long err = PTR_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 @@ -2697,29 +2850,25 @@ retry_avoidcopy: * may get SIGKILLed if it later faults. */ if (outside_reserve) { + page_cache_release(old_page); BUG_ON(huge_pte_none(pte)); - if (unmap_ref_private(mm, vma, old_page, address)) { - BUG_ON(huge_pte_none(pte)); - spin_lock(ptl); - ptep = huge_pte_offset(mm, address & huge_page_mask(h)); - if (likely(ptep && - pte_same(huge_ptep_get(ptep), pte))) - goto retry_avoidcopy; - /* - * race occurs while re-acquiring page table - * lock, and our job is done. - */ - return 0; - } - WARN_ON_ONCE(1); + unmap_ref_private(mm, vma, old_page, address); + BUG_ON(huge_pte_none(pte)); + spin_lock(ptl); + ptep = huge_pte_offset(mm, address & huge_page_mask(h)); + if (likely(ptep && + pte_same(huge_ptep_get(ptep), pte))) + goto retry_avoidcopy; + /* + * race occurs while re-acquiring page table + * lock, and our job is done. + */ + return 0; } - /* Caller expects lock to be held */ - spin_lock(ptl); - if (err == -ENOMEM) - return VM_FAULT_OOM; - else - return VM_FAULT_SIGBUS; + ret = (PTR_ERR(new_page) == -ENOMEM) ? + VM_FAULT_OOM : VM_FAULT_SIGBUS; + goto out_release_old; } /* @@ -2727,11 +2876,8 @@ retry_avoidcopy: * anon_vma prepared. */ if (unlikely(anon_vma_prepare(vma))) { - page_cache_release(new_page); - page_cache_release(old_page); - /* Caller expects lock to be held */ - spin_lock(ptl); - return VM_FAULT_OOM; + ret = VM_FAULT_OOM; + goto out_release_all; } copy_user_huge_page(new_page, old_page, address, vma, @@ -2741,6 +2887,7 @@ retry_avoidcopy: mmun_start = address & huge_page_mask(h); mmun_end = mmun_start + huge_page_size(h); mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); + /* * Retake the page table lock to check for racing updates * before the page tables are altered @@ -2761,12 +2908,13 @@ retry_avoidcopy: } spin_unlock(ptl); mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); +out_release_all: page_cache_release(new_page); +out_release_old: page_cache_release(old_page); - /* Caller expects lock to be held */ - spin_lock(ptl); - return 0; + spin_lock(ptl); /* Caller expects lock to be held */ + return ret; } /* Return the pagecache page at a given address within a VMA */ |