From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 25F67C433E7 for ; Fri, 16 Oct 2020 03:07:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C4F7A20B1F for ; Fri, 16 Oct 2020 03:07:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602817628; bh=bmZG9Q5o0pWuIWuG6pBpUcMhMJtmnXLGbV79hYoXNIA=; h=Date:From:To:Subject:In-Reply-To:Reply-To:List-ID:From; b=yijnxfJk4uzZwwW2kjPOCdTQ4KJkydW1Q4358ZRYE2TI9/XkF0jw57ixBZDsvyYmm CLHmcLV999Gyo0EfvuuI6mmf3dhWzvzqft5HJL1zfzbyy8Q3IQBSxO9OaDUzjjl+y5 jNUW6LrPLOIV6XGSqM/zU1mxIdArkjsqUsXBiIak= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404479AbgJPDHI (ORCPT ); Thu, 15 Oct 2020 23:07:08 -0400 Received: from mail.kernel.org ([198.145.29.99]:45144 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404488AbgJPDHH (ORCPT ); Thu, 15 Oct 2020 23:07:07 -0400 Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4065F20878; Fri, 16 Oct 2020 03:07:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602817627; bh=bmZG9Q5o0pWuIWuG6pBpUcMhMJtmnXLGbV79hYoXNIA=; h=Date:From:To:Subject:In-Reply-To:From; b=YmhGKxNtEXc9nrVhe16i3cfqsSDcMi+KOR6/cGPw6CaIH58mjy2vZUOqe6QyvYyqU 8KIM/VHFsNY5ktLsGWNw1nYUEBrDcn6tCKNLlxcP5SHkrf+QjZ/EolLQMsCF7yj286 ovuAjCNly/Aq6EO9x1ozXnLE6vbg8aspGgG58exM= Date: Thu, 15 Oct 2020 20:07:05 -0700 From: Andrew Morton To: akpm@linux-foundation.org, aneesh.kumar@linux.ibm.com, aneesh.kumar@linux.vnet.ibm.com, aris@ruivo.org, cai@lca.pw, dave.hansen@intel.com, david@redhat.com, mhocko@kernel.org, mike.kravetz@oracle.com, mm-commits@vger.kernel.org, naoya.horiguchi@nec.com, osalvador@suse.com, osalvador@suse.de, tony.luck@intel.com, torvalds@linux-foundation.org, zeil@yandex-team.ru Subject: [patch 048/156] mm,hwpoison: rework soft offline for free pages Message-ID: <20201016030705.p7Z7LjGUa%akpm@linux-foundation.org> In-Reply-To: <20201015194043.84cda0c1d6ca2a6847f2384a@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org 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: https://lkml.kernel.org/r/20200922135650.1634-9-osalvador@suse.de Signed-off-by: Oscar Salvador Acked-by: Naoya Horiguchi Cc: "Aneesh Kumar K.V" Cc: Aneesh Kumar K.V Cc: Aristeu Rozanski Cc: Dave Hansen Cc: David Hildenbrand Cc: Dmitry Yakunin Cc: Michal Hocko Cc: Mike Kravetz Cc: Oscar Salvador Cc: Qian Cai 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 @@ -432,6 +432,7 @@ 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 @@ -65,6 +65,13 @@ 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) +{ + SetPageHWPoison(page); + page_ref_inc(page); + num_poisoned_pages_inc(); +} + #if defined(CONFIG_HWPOISON_INJECT) || defined(CONFIG_HWPOISON_INJECT_MODULE) u32 hwpoison_filter_enable = 0; @@ -1884,14 +1891,13 @@ 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 @@ -8778,6 +8778,74 @@ 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. _