diff options
| -rw-r--r-- | include/linux/hugetlb.h | 6 | ||||
| -rw-r--r-- | mm/hugetlb.c | 26 | ||||
| -rw-r--r-- | mm/memory_hotplug.c | 4 |
3 files changed, 27 insertions, 9 deletions
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index c26d4638f665..fe99e6f956e2 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -450,8 +450,8 @@ 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); +extern int dissolve_free_huge_pages(unsigned long start_pfn, + unsigned long end_pfn); static inline bool hugepage_migration_supported(struct hstate *h) { #ifdef CONFIG_ARCH_ENABLE_HUGEPAGE_MIGRATION @@ -518,7 +518,7 @@ static inline pgoff_t basepage_index(struct page *page) { return page->index; } -#define dissolve_free_huge_pages(s, e) do {} while (0) +#define dissolve_free_huge_pages(s, e) 0 #define hugepage_migration_supported(h) false static inline spinlock_t *huge_pte_lockptr(struct hstate *h, diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 603bdd01ec2c..91ae1f567997 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1437,22 +1437,32 @@ static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, /* * Dissolve a given free hugepage into free buddy pages. This function does - * nothing for in-use (including surplus) hugepages. + * nothing for in-use (including surplus) hugepages. Returns -EBUSY if the + * number of free hugepages would be reduced below the number of reserved + * hugepages. */ -static void dissolve_free_huge_page(struct page *page) +static int dissolve_free_huge_page(struct page *page) { + int rc = 0; + spin_lock(&hugetlb_lock); if (PageHuge(page) && !page_count(page)) { struct page *head = compound_head(page); struct hstate *h = page_hstate(head); int nid = page_to_nid(head); + if (h->free_huge_pages - h->resv_huge_pages == 0) { + rc = -EBUSY; + goto out; + } list_del(&head->lru); h->free_huge_pages--; h->free_huge_pages_node[nid]--; h->max_huge_pages--; update_and_free_page(h, head); } +out: spin_unlock(&hugetlb_lock); + return rc; } /* @@ -1460,16 +1470,22 @@ static void dissolve_free_huge_page(struct page *page) * make specified memory blocks removable from the system. * Note that this will dissolve a free gigantic hugepage completely, if any * part of it lies within the given range. + * Also note that if dissolve_free_huge_page() returns with an error, all + * free hugepages that were dissolved before that error are lost. */ -void dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) +int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) { unsigned long pfn; + int rc = 0; if (!hugepages_supported()) - return; + return rc; for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) - dissolve_free_huge_page(pfn_to_page(pfn)); + if (rc = dissolve_free_huge_page(pfn_to_page(pfn))) + break; + + return rc; } /* diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 9d29ba0f7192..962927309b6e 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1945,7 +1945,9 @@ repeat: * 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); + ret = dissolve_free_huge_pages(start_pfn, end_pfn); + if (ret) + goto failed_removal; /* check again */ offlined_pages = check_pages_isolated(start_pfn, end_pfn); if (offlined_pages < 0) { |