diff options
| -rw-r--r-- | include/linux/hugetlb.h | 6 | ||||
| -rw-r--r-- | mm/hugetlb.c | 71 | ||||
| -rw-r--r-- | mm/memory_hotplug.c | 42 | ||||
| -rw-r--r-- | mm/page_alloc.c | 11 | ||||
| -rw-r--r-- | mm/page_isolation.c | 14 |
5 files changed, 135 insertions, 9 deletions
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index d1db007..2e02c4e 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -68,6 +68,7 @@ void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed); int dequeue_hwpoisoned_huge_page(struct page *page); bool isolate_huge_page(struct page *page, struct list_head *list); void putback_active_hugepage(struct page *page); +bool is_hugepage_active(struct page *page); void copy_huge_page(struct page *dst, struct page *src); #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE @@ -138,6 +139,7 @@ static inline int dequeue_hwpoisoned_huge_page(struct page *page) #define isolate_huge_page(p, l) false #define putback_active_hugepage(p) do {} while (0) +#define is_hugepage_active(x) false static inline void copy_huge_page(struct page *dst, struct page *src) { } @@ -377,6 +379,9 @@ static inline pgoff_t basepage_index(struct page *page) return __basepage_index(page); } +extern void dissolve_free_huge_pages(unsigned long start_pfn, + unsigned long end_pfn); + #else /* CONFIG_HUGETLB_PAGE */ struct hstate {}; #define alloc_huge_page_node(h, nid) NULL @@ -403,6 +408,7 @@ static inline pgoff_t basepage_index(struct page *page) { return page->index; } +#define dissolve_free_huge_pages(s, e) do {} while (0) #endif /* CONFIG_HUGETLB_PAGE */ #endif /* _LINUX_HUGETLB_H */ diff --git a/mm/hugetlb.c b/mm/hugetlb.c index d37b3b9..fb4293b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -21,6 +21,7 @@ #include <linux/rmap.h> #include <linux/swap.h> #include <linux/swapops.h> +#include <linux/page-isolation.h> #include <asm/page.h> #include <asm/pgtable.h> @@ -522,9 +523,15 @@ static struct page *dequeue_huge_page_node(struct hstate *h, int nid) { struct page *page; - if (list_empty(&h->hugepage_freelists[nid])) + list_for_each_entry(page, &h->hugepage_freelists[nid], lru) + if (!is_migrate_isolate_page(page)) + break; + /* + * if 'non-isolated free hugepage' not found on the list, + * the allocation fails. + */ + if (&h->hugepage_freelists[nid] == &page->lru) return NULL; - page = list_entry(h->hugepage_freelists[nid].next, struct page, lru); list_move(&page->lru, &h->hugepage_activelist); set_page_refcounted(page); h->free_huge_pages--; @@ -878,6 +885,44 @@ static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, return ret; } +/* + * Dissolve a given free hugepage into free buddy pages. This function does + * nothing for in-use (including surplus) hugepages. + */ +static void dissolve_free_huge_page(struct page *page) +{ + spin_lock(&hugetlb_lock); + if (PageHuge(page) && !page_count(page)) { + struct hstate *h = page_hstate(page); + int nid = page_to_nid(page); + list_del(&page->lru); + h->free_huge_pages--; + h->free_huge_pages_node[nid]--; + update_and_free_page(h, page); + } + spin_unlock(&hugetlb_lock); +} + +/* + * Dissolve free hugepages in a given pfn range. Used by memory hotplug to + * make specified memory blocks removable from the system. + * Note that start_pfn should aligned with (minimum) hugepage size. + */ +void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) +{ + unsigned int order = 8 * sizeof(void *); + unsigned long pfn; + struct hstate *h; + + /* Set scan step to minimum hugepage size */ + for_each_hstate(h) + if (order > huge_page_order(h)) + order = huge_page_order(h); + VM_BUG_ON(!IS_ALIGNED(start_pfn, 1 << order)); + for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order) + dissolve_free_huge_page(pfn_to_page(pfn)); +} + static struct page *alloc_buddy_huge_page(struct hstate *h, int nid) { struct page *page; @@ -3457,3 +3502,25 @@ void putback_active_hugepage(struct page *page) spin_unlock(&hugetlb_lock); put_page(page); } + +bool is_hugepage_active(struct page *page) +{ + VM_BUG_ON(!PageHuge(page)); + /* + * This function can be called for a tail page because the caller, + * scan_movable_pages, scans through a given pfn-range which typically + * covers one memory block. In systems using gigantic hugepage (1GB + * for x86_64,) a hugepage is larger than a memory block, and we don't + * support migrating such large hugepages for now, so return false + * when called for tail pages. + */ + if (PageTail(page)) + return false; + /* + * Refcount of a hwpoisoned hugepages is 1, but they are not active, + * so we should return false for them. + */ + if (unlikely(PageHWPoison(page))) + return false; + return page_count(page) > 0; +} diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index d595606..0eb1a1d 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -30,6 +30,7 @@ #include <linux/mm_inline.h> #include <linux/firmware-map.h> #include <linux/stop_machine.h> +#include <linux/hugetlb.h> #include <asm/tlbflush.h> @@ -1230,10 +1231,12 @@ static int test_pages_in_a_zone(unsigned long start_pfn, unsigned long end_pfn) } /* - * Scanning pfn is much easier than scanning lru list. - * Scan pfn from start to end and Find LRU page. + * Scan pfn range [start,end) to find movable/migratable pages (LRU pages + * and hugepages). We scan pfn because it's much easier than scanning over + * linked list. This function returns the pfn of the first found movable + * page if it's found, otherwise 0. */ -static unsigned long scan_lru_pages(unsigned long start, unsigned long end) +static unsigned long scan_movable_pages(unsigned long start, unsigned long end) { unsigned long pfn; struct page *page; @@ -1242,6 +1245,13 @@ static unsigned long scan_lru_pages(unsigned long start, unsigned long end) page = pfn_to_page(pfn); if (PageLRU(page)) return pfn; + if (PageHuge(page)) { + if (is_hugepage_active(page)) + return pfn; + else + pfn = round_up(pfn + 1, + 1 << compound_order(page)) - 1; + } } } return 0; @@ -1262,6 +1272,19 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) if (!pfn_valid(pfn)) continue; page = pfn_to_page(pfn); + + if (PageHuge(page)) { + struct page *head = compound_head(page); + pfn = page_to_pfn(head) + (1<<compound_order(head)) - 1; + if (compound_order(head) > PFN_SECTION_SHIFT) { + ret = -EBUSY; + break; + } + if (isolate_huge_page(page, &source)) + move_pages -= 1 << compound_order(head); + continue; + } + if (!get_page_unless_zero(page)) continue; /* @@ -1294,7 +1317,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) } if (!list_empty(&source)) { if (not_managed) { - putback_lru_pages(&source); + putback_movable_pages(&source); goto out; } @@ -1305,7 +1328,7 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn) ret = migrate_pages(&source, alloc_migrate_target, 0, MIGRATE_SYNC, MR_MEMORY_HOTPLUG); if (ret) - putback_lru_pages(&source); + putback_movable_pages(&source); } out: return ret; @@ -1548,8 +1571,8 @@ repeat: drain_all_pages(); } - pfn = scan_lru_pages(start_pfn, end_pfn); - if (pfn) { /* We have page on LRU */ + pfn = scan_movable_pages(start_pfn, end_pfn); + if (pfn) { /* We have movable pages */ ret = do_migrate_range(pfn, end_pfn); if (!ret) { drain = 1; @@ -1568,6 +1591,11 @@ repeat: yield(); /* drain pcp pages, this is synchronous. */ drain_all_pages(); + /* + * dissolve free hugepages in the memory block before doing offlining + * actually in order to make hugetlbfs's object counting consistent. + */ + dissolve_free_huge_pages(start_pfn, end_pfn); /* check again */ offlined_pages = check_pages_isolated(start_pfn, end_pfn); if (offlined_pages < 0) { diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7c3f8d7..f7cc08d 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -6008,6 +6008,17 @@ bool has_unmovable_pages(struct zone *zone, struct page *page, int count, continue; page = pfn_to_page(check); + + /* + * Hugepages are not in LRU lists, but they're movable. + * We need not scan over tail pages bacause we don't + * handle each tail page individually in migration. + */ + if (PageHuge(page)) { + iter = round_up(iter + 1, 1<<compound_order(page)) - 1; + continue; + } + /* * We can't use page_count without pin a page * because another CPU can free compound page. diff --git a/mm/page_isolation.c b/mm/page_isolation.c index 0cee10f..d1473b2 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -6,6 +6,7 @@ #include <linux/page-isolation.h> #include <linux/pageblock-flags.h> #include <linux/memory.h> +#include <linux/hugetlb.h> #include "internal.h" int set_migratetype_isolate(struct page *page, bool skip_hwpoisoned_pages) @@ -252,6 +253,19 @@ struct page *alloc_migrate_target(struct page *page, unsigned long private, { gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE; + /* + * TODO: allocate a destination hugepage from a nearest neighbor node, + * accordance with memory policy of the user process if possible. For + * now as a simple work-around, we use the next node for destination. + */ + if (PageHuge(page)) { + nodemask_t src = nodemask_of_node(page_to_nid(page)); + nodemask_t dst; + nodes_complement(dst, src); + return alloc_huge_page_node(page_hstate(compound_head(page)), + next_node(page_to_nid(page), dst)); + } + if (PageHighMem(page)) gfp_mask |= __GFP_HIGHMEM; |
