From: Oscar Salvador <osalvador@xxxxxxx> Subject: mm,hwpoison: refactor soft_offline_huge_page and __soft_offline_page Merging soft_offline_huge_page and __soft_offline_page let us get rid of quite some duplicated code, and makes the code much easier to follow. Now, __soft_offline_page will handle both normal and hugetlb pages. Link: https://lkml.kernel.org/r/20200922135650.1634-11-osalvador@xxxxxxx Signed-off-by: Oscar Salvador <osalvador@xxxxxxx> Acked-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxx> Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx> Cc: Aristeu Rozanski <aris@xxxxxxxxx> Cc: Dave Hansen <dave.hansen@xxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: Dmitry Yakunin <zeil@xxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Oscar Salvador <osalvador@xxxxxxxx> Cc: Qian Cai <cai@xxxxxx> Cc: Tony Luck <tony.luck@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/memory-failure.c | 182 ++++++++++++++++++------------------------ 1 file changed, 82 insertions(+), 100 deletions(-) --- a/mm/memory-failure.c~mmhwpoison-refactor-soft_offline_huge_page-and-__soft_offline_page +++ a/mm/memory-failure.c @@ -65,13 +65,31 @@ int sysctl_memory_failure_recovery __rea atomic_long_t num_poisoned_pages __read_mostly = ATOMIC_LONG_INIT(0); -static void page_handle_poison(struct page *page, bool release) +static bool page_handle_poison(struct page *page, bool hugepage_or_freepage, bool release) { + if (hugepage_or_freepage) { + /* + * Doing this check for free pages is also fine since dissolve_free_huge_page + * returns 0 for non-hugetlb pages as well. + */ + if (dissolve_free_huge_page(page) || !take_page_off_buddy(page)) + /* + * We could fail to take off the target page from buddy + * for example due to racy page allocaiton, but that's + * acceptable because soft-offlined page is not broken + * and if someone really want to use it, they should + * take it. + */ + return false; + } + SetPageHWPoison(page); if (release) put_page(page); page_ref_inc(page); num_poisoned_pages_inc(); + + return true; } #if defined(CONFIG_HWPOISON_INJECT) || defined(CONFIG_HWPOISON_INJECT_MODULE) @@ -1725,63 +1743,51 @@ static int get_any_page(struct page *pag return ret; } -static int soft_offline_huge_page(struct page *page, int flags) +static bool isolate_page(struct page *page, struct list_head *pagelist) { - int ret; - unsigned long pfn = page_to_pfn(page); - struct page *hpage = compound_head(page); - LIST_HEAD(pagelist); + bool isolated = false; + bool lru = PageLRU(page); - /* - * This double-check of PageHWPoison is to avoid the race with - * memory_failure(). See also comment in __soft_offline_page(). - */ - lock_page(hpage); - if (PageHWPoison(hpage)) { - unlock_page(hpage); - put_page(hpage); - pr_info("soft offline: %#lx hugepage already poisoned\n", pfn); - return -EBUSY; + if (PageHuge(page)) { + isolated = isolate_huge_page(page, pagelist); + } else { + if (lru) + isolated = !isolate_lru_page(page); + else + isolated = !isolate_movable_page(page, ISOLATE_UNEVICTABLE); + + if (isolated) + list_add(&page->lru, pagelist); } - unlock_page(hpage); - ret = isolate_huge_page(hpage, &pagelist); + if (isolated && lru) + inc_node_page_state(page, NR_ISOLATED_ANON + + page_is_file_lru(page)); + /* - * get_any_page() and isolate_huge_page() takes a refcount each, - * so need to drop one here. + * If we succeed to isolate the page, we grabbed another refcount on + * the page, so we can safely drop the one we got from get_any_pages(). + * If we failed to isolate the page, it means that we cannot go further + * and we will return an error, so drop the reference we got from + * get_any_pages() as well. */ - put_page(hpage); - if (!ret) { - pr_info("soft offline: %#lx hugepage failed to isolate\n", pfn); - return -EBUSY; - } - - ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL, - MIGRATE_SYNC, MR_MEMORY_FAILURE); - if (ret) { - pr_info("soft offline: %#lx: hugepage migration failed %d, type %lx (%pGp)\n", - pfn, ret, page->flags, &page->flags); - if (!list_empty(&pagelist)) - putback_movable_pages(&pagelist); - if (ret > 0) - ret = -EIO; - } else { - /* - * We set PG_hwpoison only when we were able to take the page - * off the buddy. - */ - if (!dissolve_free_huge_page(page) && take_page_off_buddy(page)) - page_handle_poison(page, false); - else - ret = -EBUSY; - } - return ret; + put_page(page); + return isolated; } -static int __soft_offline_page(struct page *page, int flags) +/* + * __soft_offline_page handles hugetlb-pages and non-hugetlb pages. + * If the page is a non-dirty unmapped page-cache page, it simply invalidates. + * If the page is mapped, it migrates the contents over. + */ +static int __soft_offline_page(struct page *page) { - int ret; + int ret = 0; unsigned long pfn = page_to_pfn(page); + struct page *hpage = compound_head(page); + char const *msg_page[] = {"page", "hugepage"}; + bool huge = PageHuge(page); + LIST_HEAD(pagelist); /* * Check PageHWPoison again inside page lock because PageHWPoison @@ -1790,98 +1796,74 @@ static int __soft_offline_page(struct pa * so there's no race between soft_offline_page() and memory_failure(). */ lock_page(page); - wait_on_page_writeback(page); + if (!PageHuge(page)) + wait_on_page_writeback(page); if (PageHWPoison(page)) { unlock_page(page); put_page(page); pr_info("soft offline: %#lx page already poisoned\n", pfn); return -EBUSY; } - /* - * Try to invalidate first. This should work for - * non dirty unmapped page cache pages. - */ - ret = invalidate_inode_page(page); + + if (!PageHuge(page)) + /* + * Try to invalidate first. This should work for + * non dirty unmapped page cache pages. + */ + ret = invalidate_inode_page(page); unlock_page(page); + /* * RED-PEN would be better to keep it isolated here, but we * would need to fix isolation locking first. */ - if (ret == 1) { + if (ret) { pr_info("soft_offline: %#lx: invalidated\n", pfn); - page_handle_poison(page, true); + page_handle_poison(page, false, true); return 0; } - /* - * Simple invalidation didn't work. - * Try to migrate to a new page instead. migrate.c - * handles a large number of cases for us. - */ - if (PageLRU(page)) - ret = isolate_lru_page(page); - else - ret = isolate_movable_page(page, ISOLATE_UNEVICTABLE); - /* - * Drop page reference which is came from get_any_page() - * successful isolate_lru_page() already took another one. - */ - put_page(page); - if (!ret) { - LIST_HEAD(pagelist); - /* - * After isolated lru page, the PageLRU will be cleared, - * so use !__PageMovable instead for LRU page's mapping - * cannot have PAGE_MAPPING_MOVABLE. - */ - if (!__PageMovable(page)) - inc_node_page_state(page, NR_ISOLATED_ANON + - page_is_file_lru(page)); - list_add(&page->lru, &pagelist); + if (isolate_page(hpage, &pagelist)) { ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL, MIGRATE_SYNC, MR_MEMORY_FAILURE); if (!ret) { - page_handle_poison(page, true); + bool release = !huge; + + if (!page_handle_poison(page, huge, release)) + ret = -EBUSY; } else { if (!list_empty(&pagelist)) putback_movable_pages(&pagelist); - pr_info("soft offline: %#lx: migration failed %d, type %lx (%pGp)\n", - pfn, ret, page->flags, &page->flags); + pr_info("soft offline: %#lx: %s migration failed %d, type %lx (%pGp)\n", + pfn, msg_page[huge], ret, page->flags, &page->flags); if (ret > 0) ret = -EIO; } } else { - pr_info("soft offline: %#lx: isolation failed: %d, page count %d, type %lx (%pGp)\n", - pfn, ret, page_count(page), page->flags, &page->flags); + pr_info("soft offline: %#lx: %s isolation failed: %d, page count %d, type %lx (%pGp)\n", + pfn, msg_page[huge], ret, page_count(page), page->flags, &page->flags); + ret = -EBUSY; } return ret; } -static int soft_offline_in_use_page(struct page *page, int flags) +static int soft_offline_in_use_page(struct page *page) { - int ret; struct page *hpage = compound_head(page); if (!PageHuge(page) && PageTransHuge(hpage)) if (try_to_split_thp_page(page, "soft offline") < 0) return -EBUSY; - - if (PageHuge(page)) - ret = soft_offline_huge_page(page, flags); - else - ret = __soft_offline_page(page, flags); - return ret; + return __soft_offline_page(page); } static int soft_offline_free_page(struct page *page) { - int rc = -EBUSY; + int rc = 0; - if (!dissolve_free_huge_page(page) && take_page_off_buddy(page)) { - page_handle_poison(page, false); - rc = 0; - } + if (!page_handle_poison(page, true, false)) + rc = -EBUSY; return rc; } @@ -1932,7 +1914,7 @@ int soft_offline_page(unsigned long pfn, put_online_mems(); if (ret > 0) - ret = soft_offline_in_use_page(page, flags); + ret = soft_offline_in_use_page(page); else if (ret == 0) ret = soft_offline_free_page(page); _
