From mboxrd@z Thu Jan 1 00:00:00 1970 From: akpm@linux-foundation.org Subject: + mmhwpoison-rework-soft-offline-for-free-pages.patch added to -mm tree Date: Wed, 24 Jun 2020 12:19:44 -0700 Message-ID: <20200624191944.crND3%akpm@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:60136 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405057AbgFXTTr (ORCPT ); Wed, 24 Jun 2020 15:19:47 -0400 Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: mm-commits@vger.kernel.org, zeil@yandex-team.ru, tony.luck@intel.com, naoya.horiguchi@nec.com, mike.kravetz@oracle.com, mhocko@kernel.org, david@redhat.com, dave.hansen@intel.com, aneesh.kumar@linux.vnet.ibm.com, aneesh.kumar@linux.ibm.com, osalvador@suse.de The patch titled Subject: mm,hwpoison: rework soft offline for free pages has been added to the -mm tree. Its filename is mmhwpoison-rework-soft-offline-for-free-pages.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/mmhwpoison-rework-soft-offline-for-free-pages.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/mmhwpoison-rework-soft-offline-for-free-pages.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Oscar Salvador Subject: mm,hwpoison: rework soft offline for free pages When trying to soft-offline a free page, we need to first take it off the buddy allocator. Once we know is out of reach, we can safely flag it as poisoned. take_page_off_buddy will be used to take a page meant to be poisoned off the buddy allocator. take_page_off_buddy calls break_down_buddy_pages, which splits a higher-order page in case our page belongs to one. Once the page is under our control, we call page_handle_poison to set it as poisoned and grab a refcount on it. Link: http://lkml.kernel.org/r/20200624150137.7052-12-nao.horiguchi@gmail.com Signed-off-by: Oscar Salvador Signed-off-by: Naoya Horiguchi Cc: "Aneesh Kumar K.V" Cc: Aneesh Kumar K.V Cc: Dave Hansen Cc: David Hildenbrand Cc: Dmitry Yakunin Cc: Michal Hocko Cc: Mike Kravetz Cc: Tony Luck Signed-off-by: Andrew Morton --- include/linux/page-flags.h | 1 mm/memory-failure.c | 18 ++++++--- mm/page_alloc.c | 68 +++++++++++++++++++++++++++++++++++ 3 files changed, 81 insertions(+), 6 deletions(-) --- a/include/linux/page-flags.h~mmhwpoison-rework-soft-offline-for-free-pages +++ a/include/linux/page-flags.h @@ -423,6 +423,7 @@ PAGEFLAG(HWPoison, hwpoison, PF_ANY) TESTSCFLAG(HWPoison, hwpoison, PF_ANY) #define __PG_HWPOISON (1UL << PG_hwpoison) extern bool set_hwpoison_free_buddy_page(struct page *page); +extern bool take_page_off_buddy(struct page *page); #else PAGEFLAG_FALSE(HWPoison) static inline bool set_hwpoison_free_buddy_page(struct page *page) --- a/mm/memory-failure.c~mmhwpoison-rework-soft-offline-for-free-pages +++ a/mm/memory-failure.c @@ -78,6 +78,13 @@ EXPORT_SYMBOL_GPL(hwpoison_filter_dev_mi EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask); EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value); +static void page_handle_poison(struct page *page) +{ + SetPageHWPoison(page); + page_ref_inc(page); + num_poisoned_pages_inc(); +} + static int hwpoison_filter_dev(struct page *p) { struct address_space *mapping; @@ -1876,14 +1883,13 @@ static int soft_offline_in_use_page(stru static int soft_offline_free_page(struct page *page) { - int rc = dissolve_free_huge_page(page); + int rc = -EBUSY; - if (!rc) { - if (set_hwpoison_free_buddy_page(page)) - num_poisoned_pages_inc(); - else - rc = -EBUSY; + if (!dissolve_free_huge_page(page) && take_page_off_buddy(page)) { + page_handle_poison(page); + rc = 0; } + return rc; } --- a/mm/page_alloc.c~mmhwpoison-rework-soft-offline-for-free-pages +++ a/mm/page_alloc.c @@ -8782,6 +8782,74 @@ bool is_free_buddy_page(struct page *pag #ifdef CONFIG_MEMORY_FAILURE /* + * Break down a higher-order page in sub-pages, and keep our target out of + * buddy allocator. + */ +static void break_down_buddy_pages(struct zone *zone, struct page *page, + struct page *target, int low, int high, + int migratetype) +{ + unsigned long size = 1 << high; + struct page *current_buddy, *next_page; + + while (high > low) { + high--; + size >>= 1; + + if (target >= &page[size]) { + next_page = page + size; + current_buddy = page; + } else { + next_page = page; + current_buddy = page + size; + } + + if (set_page_guard(zone, current_buddy, high, migratetype)) + continue; + + if (current_buddy != target) { + add_to_free_list(current_buddy, zone, high, migratetype); + set_page_order(current_buddy, high); + page = next_page; + } + } +} + +/* + * Take a page that will be marked as poisoned off the buddy allocator. + */ +bool take_page_off_buddy(struct page *page) +{ + struct zone *zone = page_zone(page); + unsigned long pfn = page_to_pfn(page); + unsigned long flags; + unsigned int order; + bool ret = false; + + spin_lock_irqsave(&zone->lock, flags); + for (order = 0; order < MAX_ORDER; order++) { + struct page *page_head = page - (pfn & ((1 << order) - 1)); + int buddy_order = page_order(page_head); + + if (PageBuddy(page_head) && buddy_order >= order) { + unsigned long pfn_head = page_to_pfn(page_head); + int migratetype = get_pfnblock_migratetype(page_head, + pfn_head); + + del_page_from_free_list(page_head, zone, buddy_order); + break_down_buddy_pages(zone, page_head, page, 0, + buddy_order, migratetype); + ret = true; + break; + } + if (page_count(page_head) > 0) + break; + } + spin_unlock_irqrestore(&zone->lock, flags); + return ret; +} + +/* * Set PG_hwpoison flag if a given page is confirmed to be a free page. This * test is performed under the zone lock to prevent a race against page * allocation. _ Patches currently in -mm which might be from osalvador@suse.de are mmmadvise-refactor-madvise_inject_error.patch mmhwpoison-un-export-get_hwpoison_page-and-make-it-static.patch mmhwpoison-kill-put_hwpoison_page.patch mmhwpoison-unify-thp-handling-for-hard-and-soft-offline.patch mmhwpoison-rework-soft-offline-for-free-pages.patch mmhwpoison-rework-soft-offline-for-in-use-pages.patch mmhwpoison-refactor-soft_offline_huge_page-and-__soft_offline_page.patch mmhwpoison-return-0-if-the-page-is-already-poisoned-in-soft-offline.patch