#include <linux/numa.h>
#include <linux/llist.h>
#include <linux/cma.h>
+#include <linux/migrate.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <linux/node.h>
#include <linux/page_owner.h>
#include "internal.h"
+#include "hugetlb_vmemmap.h"
int hugetlb_max_hstate __read_mostly;
unsigned int default_hstate_idx;
return alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask);
}
-static void prep_new_huge_page(struct hstate *h, struct page *page, int nid);
-static void prep_compound_gigantic_page(struct page *page, unsigned int order);
#else /* !CONFIG_CONTIG_ALLOC */
static struct page *alloc_gigantic_page(struct hstate *h, gfp_t gfp_mask,
int nid, nodemask_t *nodemask)
h->nr_huge_pages_node[nid]--;
}
-static void update_and_free_page(struct hstate *h, struct page *page)
+static void add_hugetlb_page(struct hstate *h, struct page *page,
+ bool adjust_surplus)
+{
+ int zeroed;
+ int nid = page_to_nid(page);
+
+ VM_BUG_ON_PAGE(!HPageVmemmapOptimized(page), page);
+
+ lockdep_assert_held(&hugetlb_lock);
+
+ INIT_LIST_HEAD(&page->lru);
+ h->nr_huge_pages++;
+ h->nr_huge_pages_node[nid]++;
+
+ if (adjust_surplus) {
+ h->surplus_huge_pages++;
+ h->surplus_huge_pages_node[nid]++;
+ }
+
+ set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
+ set_page_private(page, 0);
+ SetHPageVmemmapOptimized(page);
+
+ /*
+ * This page is now managed by the hugetlb allocator and has
+ * no users -- drop the last reference.
+ */
+ zeroed = put_page_testzero(page);
+ VM_BUG_ON_PAGE(!zeroed, page);
+ arch_clear_hugepage_flags(page);
+ enqueue_huge_page(h, page);
+}
+
+static void __update_and_free_page(struct hstate *h, struct page *page)
{
int i;
struct page *subpage = page;
if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported())
return;
+ if (alloc_huge_page_vmemmap(h, page)) {
+ spin_lock_irq(&hugetlb_lock);
+ /*
+ * If we cannot allocate vmemmap pages, just refuse to free the
+ * page and put the page back on the hugetlb free list and treat
+ * as a surplus page.
+ */
+ add_hugetlb_page(h, page, true);
+ spin_unlock_irq(&hugetlb_lock);
+ return;
+ }
+
for (i = 0; i < pages_per_huge_page(h);
i++, subpage = mem_map_next(subpage, page, i)) {
subpage->flags &= ~(1 << PG_locked | 1 << PG_error |
}
}
+/*
+ * As update_and_free_page() can be called under any context, so we cannot
+ * use GFP_KERNEL to allocate vmemmap pages. However, we can defer the
+ * actual freeing in a workqueue to prevent from using GFP_ATOMIC to allocate
+ * the vmemmap pages.
+ *
+ * free_hpage_workfn() locklessly retrieves the linked list of pages to be
+ * freed and frees them one-by-one. As the page->mapping pointer is going
+ * to be cleared in free_hpage_workfn() anyway, it is reused as the llist_node
+ * structure of a lockless linked list of huge pages to be freed.
+ */
+static LLIST_HEAD(hpage_freelist);
+
+static void free_hpage_workfn(struct work_struct *work)
+{
+ struct llist_node *node;
+
+ node = llist_del_all(&hpage_freelist);
+
+ while (node) {
+ struct page *page;
+ struct hstate *h;
+
+ page = container_of((struct address_space **)node,
+ struct page, mapping);
+ node = node->next;
+ page->mapping = NULL;
+ /*
+ * The VM_BUG_ON_PAGE(!PageHuge(page), page) in page_hstate()
+ * is going to trigger because a previous call to
+ * remove_hugetlb_page() will set_compound_page_dtor(page,
+ * NULL_COMPOUND_DTOR), so do not use page_hstate() directly.
+ */
+ h = size_to_hstate(page_size(page));
+
+ __update_and_free_page(h, page);
+
+ cond_resched();
+ }
+}
+static DECLARE_WORK(free_hpage_work, free_hpage_workfn);
+
+static inline void flush_free_hpage_work(struct hstate *h)
+{
+ if (free_vmemmap_pages_per_hpage(h))
+ flush_work(&free_hpage_work);
+}
+
+static void update_and_free_page(struct hstate *h, struct page *page,
+ bool atomic)
+{
+ if (!HPageVmemmapOptimized(page) || !atomic) {
+ __update_and_free_page(h, page);
+ return;
+ }
+
+ /*
+ * Defer freeing to avoid using GFP_ATOMIC to allocate vmemmap pages.
+ *
+ * Only call schedule_work() if hpage_freelist is previously
+ * empty. Otherwise, schedule_work() had been called but the workfn
+ * hasn't retrieved the list yet.
+ */
+ if (llist_add((struct llist_node *)&page->mapping, &hpage_freelist))
+ schedule_work(&free_hpage_work);
+}
+
static void update_and_free_pages_bulk(struct hstate *h, struct list_head *list)
{
struct page *page, *t_page;
list_for_each_entry_safe(page, t_page, list, lru) {
- update_and_free_page(h, page);
+ update_and_free_page(h, page, false);
cond_resched();
}
}
if (HPageTemporary(page)) {
remove_hugetlb_page(h, page, false);
spin_unlock_irqrestore(&hugetlb_lock, flags);
- update_and_free_page(h, page);
+ update_and_free_page(h, page, true);
} else if (h->surplus_huge_pages_node[nid]) {
/* remove the page from active list */
remove_hugetlb_page(h, page, true);
spin_unlock_irqrestore(&hugetlb_lock, flags);
- update_and_free_page(h, page);
+ update_and_free_page(h, page, true);
} else {
arch_clear_hugepage_flags(page);
enqueue_huge_page(h, page);
h->nr_huge_pages_node[nid]++;
}
-static void __prep_new_huge_page(struct page *page)
+static void __prep_new_huge_page(struct hstate *h, struct page *page)
{
+ free_huge_page_vmemmap(h, page);
INIT_LIST_HEAD(&page->lru);
set_compound_page_dtor(page, HUGETLB_PAGE_DTOR);
hugetlb_set_page_subpool(page, NULL);
static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
{
- __prep_new_huge_page(page);
+ __prep_new_huge_page(h, page);
spin_lock_irq(&hugetlb_lock);
__prep_account_new_huge_page(h, nid);
spin_unlock_irq(&hugetlb_lock);
}
-static void prep_compound_gigantic_page(struct page *page, unsigned int order)
+static bool prep_compound_gigantic_page(struct page *page, unsigned int order)
{
- int i;
+ int i, j;
int nr_pages = 1 << order;
struct page *p = page + 1;
* after get_user_pages().
*/
__ClearPageReserved(p);
+ /*
+ * Subtle and very unlikely
+ *
+ * Gigantic 'page allocators' such as memblock or cma will
+ * return a set of pages with each page ref counted. We need
+ * to turn this set of pages into a compound page with tail
+ * page ref counts set to zero. Code such as speculative page
+ * cache adding could take a ref on a 'to be' tail page.
+ * We need to respect any increased ref count, and only set
+ * the ref count to zero if count is currently 1. If count
+ * is not 1, we call synchronize_rcu in the hope that a rcu
+ * grace period will cause ref count to drop and then retry.
+ * If count is still inflated on retry we return an error and
+ * must discard the pages.
+ */
+ if (!page_ref_freeze(p, 1)) {
+ pr_info("HugeTLB unexpected inflated ref count on freshly allocated page\n");
+ synchronize_rcu();
+ if (!page_ref_freeze(p, 1))
+ goto out_error;
+ }
set_page_count(p, 0);
set_compound_head(p, page);
}
atomic_set(compound_mapcount_ptr(page), -1);
atomic_set(compound_pincount_ptr(page), 0);
+ return true;
+
+out_error:
+ /* undo tail page modifications made above */
+ p = page + 1;
+ for (j = 1; j < i; j++, p = mem_map_next(p, page, j)) {
+ clear_compound_head(p);
+ set_page_refcounted(p);
+ }
+ /* need to clear PG_reserved on remaining tail pages */
+ for (; j < nr_pages; j++, p = mem_map_next(p, page, j))
+ __ClearPageReserved(p);
+ set_compound_order(page, 0);
+ page[1].compound_nr = 0;
+ __ClearPageHead(page);
+ return false;
}
/*
nodemask_t *node_alloc_noretry)
{
struct page *page;
+ bool retry = false;
+retry:
if (hstate_is_gigantic(h))
page = alloc_gigantic_page(h, gfp_mask, nid, nmask);
else
if (!page)
return NULL;
- if (hstate_is_gigantic(h))
- prep_compound_gigantic_page(page, huge_page_order(h));
+ if (hstate_is_gigantic(h)) {
+ if (!prep_compound_gigantic_page(page, huge_page_order(h))) {
+ /*
+ * Rare failure to convert pages to compound page.
+ * Free pages and try again - ONCE!
+ */
+ free_gigantic_page(page, huge_page_order(h));
+ if (!retry) {
+ retry = true;
+ goto retry;
+ }
+ pr_warn("HugeTLB page can not be used due to unexpected inflated ref count\n");
+ return NULL;
+ }
+ }
prep_new_huge_page(h, page, page_to_nid(page));
return page;
* nothing for in-use hugepages and non-hugepages.
* This function returns values like below:
*
- * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
- * (allocated or reserved.)
- * 0: successfully dissolved free hugepages or the page is not a
- * hugepage (considered as already dissolved)
+ * -ENOMEM: failed to allocate vmemmap pages to free the freed hugepages
+ * when the system is under memory pressure and the feature of
+ * freeing unused vmemmap pages associated with each hugetlb page
+ * is enabled.
+ * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
+ * (allocated or reserved.)
+ * 0: successfully dissolved free hugepages or the page is not a
+ * hugepage (considered as already dissolved)
*/
int dissolve_free_huge_page(struct page *page)
{
goto retry;
}
- /*
- * Move PageHWPoison flag from head page to the raw error page,
- * which makes any subpages rather than the error page reusable.
- */
- if (PageHWPoison(head) && page != head) {
- SetPageHWPoison(page);
- ClearPageHWPoison(head);
- }
remove_hugetlb_page(h, head, false);
h->max_huge_pages--;
spin_unlock_irq(&hugetlb_lock);
- update_and_free_page(h, head);
- return 0;
+
+ /*
+ * Normally update_and_free_page will allocate required vmemmmap
+ * before freeing the page. update_and_free_page will fail to
+ * free the page if it can not allocate required vmemmap. We
+ * need to adjust max_huge_pages if the page is not freed.
+ * Attempt to allocate vmemmmap here so that we can take
+ * appropriate action on failure.
+ */
+ rc = alloc_huge_page_vmemmap(h, head);
+ if (!rc) {
+ /*
+ * Move PageHWPoison flag from head page to the raw
+ * error page, which makes any subpages rather than
+ * the error page reusable.
+ */
+ if (PageHWPoison(head) && page != head) {
+ SetPageHWPoison(page);
+ ClearPageHWPoison(head);
+ }
+ update_and_free_page(h, head, false);
+ } else {
+ spin_lock_irq(&hugetlb_lock);
+ add_hugetlb_page(h, head, false);
+ h->max_huge_pages++;
+ spin_unlock_irq(&hugetlb_lock);
+ }
+
+ return rc;
}
out:
spin_unlock_irq(&hugetlb_lock);
if (!rc) {
/*
* This indicates there is an entry in the reserve map
- * added by alloc_huge_page. We know it was added
+ * not added by alloc_huge_page. We know it was added
* before the alloc_huge_page call, otherwise
* HPageRestoreReserve would be set on the page.
* Remove the entry so that a subsequent allocation
/*
* Before dissolving the page, we need to allocate a new one for the
- * pool to remain stable. Using alloc_buddy_huge_page() allows us to
- * not having to deal with prep_new_huge_page() and avoids dealing of any
- * counters. This simplifies and let us do the whole thing under the
- * lock.
+ * pool to remain stable. Here, we allocate the page and 'prep' it
+ * by doing everything but actually updating counters and adding to
+ * the pool. This simplifies and let us do most of the processing
+ * under the lock.
*/
new_page = alloc_buddy_huge_page(h, gfp_mask, nid, NULL, NULL);
if (!new_page)
return -ENOMEM;
+ __prep_new_huge_page(h, new_page);
retry:
spin_lock_irq(&hugetlb_lock);
remove_hugetlb_page(h, old_page, false);
/*
- * new_page needs to be initialized with the standard hugetlb
- * state. This is normally done by prep_new_huge_page() but
- * that takes hugetlb_lock which is already held so we need to
- * open code it here.
* Reference count trick is needed because allocator gives us
* referenced page but the pool requires pages with 0 refcount.
*/
- __prep_new_huge_page(new_page);
__prep_account_new_huge_page(h, nid);
page_ref_dec(new_page);
enqueue_huge_page(h, new_page);
* Pages have been replaced, we can safely free the old one.
*/
spin_unlock_irq(&hugetlb_lock);
- update_and_free_page(h, old_page);
+ update_and_free_page(h, old_page, false);
}
return ret;
free_new:
spin_unlock_irq(&hugetlb_lock);
- __free_pages(new_page, huge_page_order(h));
+ update_and_free_page(h, new_page, false);
return ret;
}
return 1;
}
-static void __init prep_compound_huge_page(struct page *page,
- unsigned int order)
-{
- if (unlikely(order > (MAX_ORDER - 1)))
- prep_compound_gigantic_page(page, order);
- else
- prep_compound_page(page, order);
-}
-
-/* Put bootmem huge pages into the standard lists after mem_map is up */
+/*
+ * Put bootmem huge pages into the standard lists after mem_map is up.
+ * Note: This only applies to gigantic (order > MAX_ORDER) pages.
+ */
static void __init gather_bootmem_prealloc(void)
{
struct huge_bootmem_page *m;
struct page *page = virt_to_page(m);
struct hstate *h = m->hstate;
+ VM_BUG_ON(!hstate_is_gigantic(h));
WARN_ON(page_count(page) != 1);
- prep_compound_huge_page(page, huge_page_order(h));
- WARN_ON(PageReserved(page));
- prep_new_huge_page(h, page, page_to_nid(page));
- put_page(page); /* free it into the hugepage allocator */
+ if (prep_compound_gigantic_page(page, huge_page_order(h))) {
+ WARN_ON(PageReserved(page));
+ prep_new_huge_page(h, page, page_to_nid(page));
+ put_page(page); /* add to the hugepage allocator */
+ } else {
+ free_gigantic_page(page, huge_page_order(h));
+ pr_warn("HugeTLB page can not be used due to unexpected inflated ref count\n");
+ }
/*
- * If we had gigantic hugepages allocated at boot time, we need
- * to restore the 'stolen' pages to totalram_pages in order to
- * fix confusing memory reports from free(1) and another
- * side-effects, like CommitLimit going negative.
+ * We need to restore the 'stolen' pages to totalram_pages
+ * in order to fix confusing memory reports from free(1) and
+ * other side-effects, like CommitLimit going negative.
*/
- if (hstate_is_gigantic(h))
- adjust_managed_page_count(page, pages_per_huge_page(h));
+ adjust_managed_page_count(page, pages_per_huge_page(h));
cond_resched();
}
}
* pages in hstate via the proc/sysfs interfaces.
*/
mutex_lock(&h->resize_lock);
+ flush_free_hpage_work(h);
spin_lock_irq(&hugetlb_lock);
/*
/* free the pages after dropping lock */
spin_unlock_irq(&hugetlb_lock);
update_and_free_pages_bulk(h, &page_list);
+ flush_free_hpage_work(h);
spin_lock_irq(&hugetlb_lock);
while (count < persistent_huge_pages(h)) {
h->next_nid_to_free = first_memory_node;
snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",
huge_page_size(h)/1024);
+ hugetlb_vmemmap_init(h);
parsed_hstate = h;
}
int writable)
{
pte_t entry;
+ unsigned int shift = huge_page_shift(hstate_vma(vma));
if (writable) {
entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page,
}
entry = pte_mkyoung(entry);
entry = pte_mkhuge(entry);
- entry = arch_make_huge_pte(entry, vma, page, writable);
+ entry = arch_make_huge_pte(entry, shift, vma->vm_flags);
return entry;
}
is_hugetlb_entry_hwpoisoned(entry))) {
swp_entry_t swp_entry = pte_to_swp_entry(entry);
- if (is_write_migration_entry(swp_entry) && cow) {
+ if (is_writable_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);
+ swp_entry = make_readable_migration_entry(
+ swp_offset(swp_entry));
entry = swp_entry_to_pte(swp_entry);
set_huge_swap_pte_at(src, addr, src_pte,
entry, sz);
spin_unlock(ptl);
mmu_notifier_invalidate_range_end(&range);
out_release_all:
- restore_reserve_on_error(h, vma, haddr, new_page);
+ /* No restore in case of successful pagetable update (Break COW) */
+ if (new_page != old_page)
+ restore_reserve_on_error(h, vma, haddr, new_page);
put_page(new_page);
out_release_old:
put_page(old_page);
pte_t new_pte;
spinlock_t *ptl;
unsigned long haddr = address & huge_page_mask(h);
- bool new_page = false;
+ bool new_page, new_pagecache_page = false;
/*
* Currently, we are forced to kill the process in the event the
goto out;
retry:
+ new_page = false;
page = find_lock_page(mapping, idx);
if (!page) {
/* Check for page in userfault range */
goto retry;
goto out;
}
+ new_pagecache_page = true;
} else {
lock_page(page);
if (unlikely(anon_vma_prepare(vma))) {
spin_unlock(ptl);
backout_unlocked:
unlock_page(page);
- restore_reserve_on_error(h, vma, haddr, page);
+ /* restore reserve for newly allocated pages not in page cache */
+ if (new_page && !new_pagecache_page)
+ restore_reserve_on_error(h, vma, haddr, page);
put_page(page);
goto out;
}
struct page **pagep)
{
bool is_continue = (mode == MCOPY_ATOMIC_CONTINUE);
- struct address_space *mapping;
- pgoff_t idx;
+ struct hstate *h = hstate_vma(dst_vma);
+ struct address_space *mapping = dst_vma->vm_file->f_mapping;
+ pgoff_t idx = vma_hugecache_offset(h, dst_vma, dst_addr);
unsigned long size;
int vm_shared = dst_vma->vm_flags & VM_SHARED;
- struct hstate *h = hstate_vma(dst_vma);
pte_t _dst_pte;
spinlock_t *ptl;
- int ret;
+ int ret = -ENOMEM;
struct page *page;
int writable;
-
- mapping = dst_vma->vm_file->f_mapping;
- idx = vma_hugecache_offset(h, dst_vma, dst_addr);
+ bool new_pagecache_page = false;
if (is_continue) {
ret = -EFAULT;
/* fallback to copy_from_user outside mmap_lock */
if (unlikely(ret)) {
ret = -ENOENT;
+ /* Free the allocated page which may have
+ * consumed a reservation.
+ */
+ restore_reserve_on_error(h, dst_vma, dst_addr, page);
+ put_page(page);
+
+ /* Allocate a temporary page to hold the copied
+ * contents.
+ */
+ page = alloc_huge_page_vma(h, dst_vma, dst_addr);
+ if (!page) {
+ ret = -ENOMEM;
+ goto out;
+ }
*pagep = page;
- /* don't free the page */
+ /* Set the outparam pagep and return to the caller to
+ * copy the contents outside the lock. Don't free the
+ * page.
+ */
goto out;
}
} else {
- page = *pagep;
+ if (vm_shared &&
+ hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) {
+ put_page(*pagep);
+ ret = -EEXIST;
+ *pagep = NULL;
+ goto out;
+ }
+
+ page = alloc_huge_page(dst_vma, dst_addr, 0);
+ if (IS_ERR(page)) {
+ ret = -ENOMEM;
+ *pagep = NULL;
+ goto out;
+ }
+ copy_huge_page(page, *pagep);
+ put_page(*pagep);
*pagep = NULL;
}
ret = huge_add_to_page_cache(page, mapping, idx);
if (ret)
goto out_release_nounlock;
+ new_pagecache_page = true;
}
ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
if (vm_shared || is_continue)
unlock_page(page);
out_release_nounlock:
- restore_reserve_on_error(h, dst_vma, dst_addr, page);
+ if (!new_pagecache_page)
+ restore_reserve_on_error(h, dst_vma, dst_addr, page);
put_page(page);
goto out;
}
continue;
}
- refs = min3(pages_per_huge_page(h) - pfn_offset,
- (vma->vm_end - vaddr) >> PAGE_SHIFT, remainder);
+ /* vaddr may not be aligned to PAGE_SIZE */
+ refs = min3(pages_per_huge_page(h) - pfn_offset, remainder,
+ (vma->vm_end - ALIGN_DOWN(vaddr, PAGE_SIZE)) >> PAGE_SHIFT);
if (pages || vmas)
record_subpages_vmas(mem_map_offset(page, pfn_offset),
if (unlikely(is_hugetlb_entry_migration(pte))) {
swp_entry_t entry = pte_to_swp_entry(pte);
- if (is_write_migration_entry(entry)) {
+ if (is_writable_migration_entry(entry)) {
pte_t newpte;
- make_migration_entry_read(&entry);
+ entry = make_readable_migration_entry(
+ swp_offset(entry));
newpte = swp_entry_to_pte(entry);
set_huge_swap_pte_at(mm, address, ptep,
newpte, huge_page_size(h));
}
if (!huge_pte_none(pte)) {
pte_t old_pte;
+ unsigned int shift = huge_page_shift(hstate_vma(vma));
old_pte = huge_ptep_modify_prot_start(vma, address, ptep);
pte = pte_mkhuge(huge_pte_modify(old_pte, newprot));
- pte = arch_make_huge_pte(pte, vma, NULL, 0);
+ pte = arch_make_huge_pte(pte, shift, vma->vm_flags);
huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte);
pages++;
}
projects / linux-2.6-microblaze.git / blobdiff