@@ -735,7 +735,7 @@ static long hugetlbfs_fallocate(struct f
mutex_unlock(&hugetlb_fault_mutex_table[hash]);
- set_page_huge_active(page);
+ SetHPageMigratable(page);
/*
* unlock_page because locked by add_to_page_cache()
* put_page() due to reference from alloc_huge_page()
@@ -480,9 +480,13 @@ unsigned long hugetlb_get_unmapped_area(
* HPG_restore_reserve - Set when a hugetlb page consumes a reservation at
* allocation time. Cleared when page is fully instantiated. Free
* routine checks flag to restore a reservation on error paths.
+ * HPG_migratable - Set after a newly allocated page is added to the page
+ * cache and/or page tables. Indicates the page is a candidate for
+ * migration.
*/
enum hugetlb_page_flags {
HPG_restore_reserve = 0,
+ HPG_migratable,
__NR_HPAGEFLAGS,
};
@@ -525,6 +529,7 @@ static inline void ClearHPage##uname(str
* Create functions associated with hugetlb page flags
*/
HPAGEFLAG(RestoreReserve, restore_reserve)
+HPAGEFLAG(Migratable, migratable)
#ifdef CONFIG_HUGETLB_PAGE
@@ -838,8 +843,6 @@ static inline void huge_ptep_modify_prot
}
#endif
-void set_page_huge_active(struct page *page);
-
#else /* CONFIG_HUGETLB_PAGE */
struct hstate {};
@@ -592,15 +592,9 @@ static inline void ClearPageCompound(str
#ifdef CONFIG_HUGETLB_PAGE
int PageHuge(struct page *page);
int PageHeadHuge(struct page *page);
-bool page_huge_active(struct page *page);
#else
TESTPAGEFLAG_FALSE(Huge)
TESTPAGEFLAG_FALSE(HeadHuge)
-
-static inline bool page_huge_active(struct page *page)
-{
- return 0;
-}
#endif
@@ -1365,30 +1365,6 @@ struct hstate *size_to_hstate(unsigned l
}
/*
- * Test to determine whether the hugepage is "active/in-use" (i.e. being linked
- * to hstate->hugepage_activelist.)
- *
- * This function can be called for tail pages, but never returns true for them.
- */
-bool page_huge_active(struct page *page)
-{
- return PageHeadHuge(page) && PagePrivate(&page[1]);
-}
-
-/* never called for tail page */
-void set_page_huge_active(struct page *page)
-{
- VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
- SetPagePrivate(&page[1]);
-}
-
-static void clear_page_huge_active(struct page *page)
-{
- VM_BUG_ON_PAGE(!PageHeadHuge(page), page);
- ClearPagePrivate(&page[1]);
-}
-
-/*
* Internal hugetlb specific page flag. Do not use outside of the hugetlb
* code
*/
@@ -1449,7 +1425,7 @@ static void __free_huge_page(struct page
}
spin_lock(&hugetlb_lock);
- clear_page_huge_active(page);
+ ClearHPageMigratable(page);
hugetlb_cgroup_uncharge_page(hstate_index(h),
pages_per_huge_page(h), page);
hugetlb_cgroup_uncharge_page_rsvd(hstate_index(h),
@@ -4218,7 +4194,7 @@ retry_avoidcopy:
make_huge_pte(vma, new_page, 1));
page_remove_rmap(old_page, true);
hugepage_add_new_anon_rmap(new_page, vma, haddr);
- set_page_huge_active(new_page);
+ SetHPageMigratable(new_page);
/* Make the old page be freed below */
new_page = old_page;
}
@@ -4455,12 +4431,12 @@ retry:
spin_unlock(ptl);
/*
- * Only make newly allocated pages active. Existing pages found
- * in the pagecache could be !page_huge_active() if they have been
- * isolated for migration.
+ * Only set HPageMigratable in newly allocated pages. Existing pages
+ * found in the pagecache may not have HPageMigratableset if they have
+ * been isolated for migration.
*/
if (new_page)
- set_page_huge_active(page);
+ SetHPageMigratable(page);
unlock_page(page);
out:
@@ -4771,7 +4747,7 @@ int hugetlb_mcopy_atomic_pte(struct mm_s
update_mmu_cache(dst_vma, dst_addr, dst_pte);
spin_unlock(ptl);
- set_page_huge_active(page);
+ SetHPageMigratable(page);
if (vm_shared)
unlock_page(page);
ret = 0;
@@ -5610,12 +5586,13 @@ bool isolate_huge_page(struct page *page
bool ret = true;
spin_lock(&hugetlb_lock);
- if (!PageHeadHuge(page) || !page_huge_active(page) ||
+ if (!PageHeadHuge(page) ||
+ !HPageMigratable(page) ||
!get_page_unless_zero(page)) {
ret = false;
goto unlock;
}
- clear_page_huge_active(page);
+ ClearHPageMigratable(page);
list_move_tail(&page->lru, list);
unlock:
spin_unlock(&hugetlb_lock);
@@ -5625,7 +5602,7 @@ unlock:
void putback_active_hugepage(struct page *page)
{
spin_lock(&hugetlb_lock);
- set_page_huge_active(page);
+ SetHPageMigratable(page);
list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist);
spin_unlock(&hugetlb_lock);
put_page(page);
@@ -1260,7 +1260,14 @@ static int scan_movable_pages(unsigned l
if (!PageHuge(page))
continue;
head = compound_head(page);
- if (page_huge_active(head))
+ /*
+ * This test is racy as we hold no reference or lock. The
+ * hugetlb page could have been free'ed and head is no longer
+ * a hugetlb page before the following check. In such unlikely
+ * cases false positives and negatives are possible. Calling
+ * code must deal with these scenarios.
+ */
+ if (HPageMigratable(head))
goto found;
skip = compound_nr(head) - (page - head);
pfn += skip - 1;