#include <linux/hugetlb_cgroup.h>
#include <linux/gfp.h>
#include <linux/balloon_compaction.h>
+#include <linux/mmu_notifier.h>
#include <asm/tlbflush.h>
}
/*
+ * Gigantic pages are so large that we do not guarantee that page++ pointer
+ * arithmetic will work across the entire page. We need something more
+ * specialized.
+ */
+static void __copy_gigantic_page(struct page *dst, struct page *src,
+ int nr_pages)
+{
+ int i;
+ struct page *dst_base = dst;
+ struct page *src_base = src;
+
+ for (i = 0; i < nr_pages; ) {
+ cond_resched();
+ copy_highpage(dst, src);
+
+ i++;
+ dst = mem_map_next(dst, dst_base, i);
+ src = mem_map_next(src, src_base, i);
+ }
+}
+
+static void copy_huge_page(struct page *dst, struct page *src)
+{
+ int i;
+ int nr_pages;
+
+ if (PageHuge(src)) {
+ /* hugetlbfs page */
+ struct hstate *h = page_hstate(src);
+ nr_pages = pages_per_huge_page(h);
+
+ if (unlikely(nr_pages > MAX_ORDER_NR_PAGES)) {
+ __copy_gigantic_page(dst, src, nr_pages);
+ return;
+ }
+ } else {
+ /* thp page */
+ BUG_ON(!PageTransHuge(src));
+ nr_pages = hpage_nr_pages(src);
+ }
+
+ for (i = 0; i < nr_pages; i++) {
+ cond_resched();
+ copy_highpage(dst + i, src + i);
+ }
+}
+
+/*
* Copy the page to its new location
*/
void migrate_page_copy(struct page *newpage, struct page *page)
return 1;
}
+bool pmd_trans_migrating(pmd_t pmd)
+{
+ struct page *page = pmd_page(pmd);
+ return PageLocked(page);
+}
+
+void wait_migrate_huge_page(struct anon_vma *anon_vma, pmd_t *pmd)
+{
+ struct page *page = pmd_page(*pmd);
+ wait_on_page_locked(page);
+}
+
/*
* Attempt to migrate a misplaced page to the specified destination
* node. Caller is expected to have an elevated reference count on
struct page *page, int node)
{
spinlock_t *ptl;
- unsigned long haddr = address & HPAGE_PMD_MASK;
pg_data_t *pgdat = NODE_DATA(node);
int isolated = 0;
struct page *new_page = NULL;
struct mem_cgroup *memcg = NULL;
int page_lru = page_is_file_cache(page);
+ unsigned long mmun_start = address & HPAGE_PMD_MASK;
+ unsigned long mmun_end = mmun_start + HPAGE_PMD_SIZE;
+ pmd_t orig_entry;
/*
* Rate-limit the amount of data that is being migrated to a node.
WARN_ON(PageLRU(new_page));
/* Recheck the target PMD */
+ mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
ptl = pmd_lock(mm, pmd);
- if (unlikely(!pmd_same(*pmd, entry))) {
+ if (unlikely(!pmd_same(*pmd, entry) || page_count(page) != 2)) {
+fail_putback:
spin_unlock(ptl);
+ mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
/* Reverse changes made by migrate_page_copy() */
if (TestClearPageActive(new_page))
putback_lru_page(page);
mod_zone_page_state(page_zone(page),
NR_ISOLATED_ANON + page_lru, -HPAGE_PMD_NR);
- goto out_fail;
+
+ goto out_unlock;
}
/*
*/
mem_cgroup_prepare_migration(page, new_page, &memcg);
+ orig_entry = *pmd;
entry = mk_pmd(new_page, vma->vm_page_prot);
- entry = pmd_mknonnuma(entry);
- entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
entry = pmd_mkhuge(entry);
+ entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
- pmdp_clear_flush(vma, haddr, pmd);
- set_pmd_at(mm, haddr, pmd, entry);
- page_add_new_anon_rmap(new_page, vma, haddr);
+ /*
+ * Clear the old entry under pagetable lock and establish the new PTE.
+ * Any parallel GUP will either observe the old page blocking on the
+ * page lock, block on the page table lock or observe the new page.
+ * The SetPageUptodate on the new page and page_add_new_anon_rmap
+ * guarantee the copy is visible before the pagetable update.
+ */
+ flush_cache_range(vma, mmun_start, mmun_end);
+ page_add_new_anon_rmap(new_page, vma, mmun_start);
+ pmdp_clear_flush(vma, mmun_start, pmd);
+ set_pmd_at(mm, mmun_start, pmd, entry);
+ flush_tlb_range(vma, mmun_start, mmun_end);
update_mmu_cache_pmd(vma, address, &entry);
+
+ if (page_count(page) != 2) {
+ set_pmd_at(mm, mmun_start, pmd, orig_entry);
+ flush_tlb_range(vma, mmun_start, mmun_end);
+ update_mmu_cache_pmd(vma, address, &entry);
+ page_remove_rmap(new_page);
+ goto fail_putback;
+ }
+
page_remove_rmap(page);
+
/*
* Finish the charge transaction under the page table lock to
* prevent split_huge_page() from dividing up the charge
*/
mem_cgroup_end_migration(memcg, page, new_page, true);
spin_unlock(ptl);
+ mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
unlock_page(new_page);
unlock_page(page);
out_fail:
count_vm_events(PGMIGRATE_FAIL, HPAGE_PMD_NR);
out_dropref:
- entry = pmd_mknonnuma(entry);
- set_pmd_at(mm, haddr, pmd, entry);
- update_mmu_cache_pmd(vma, address, &entry);
+ ptl = pmd_lock(mm, pmd);
+ if (pmd_same(*pmd, entry)) {
+ entry = pmd_mknonnuma(entry);
+ set_pmd_at(mm, mmun_start, pmd, entry);
+ update_mmu_cache_pmd(vma, address, &entry);
+ }
+ spin_unlock(ptl);
+out_unlock:
unlock_page(page);
put_page(page);
return 0;