From patchwork Tue Dec 15 03:11:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11973883 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 40825C4361B for ; Tue, 15 Dec 2020 03:11:42 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id D044222573 for ; Tue, 15 Dec 2020 03:11:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D044222573 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 521358D0052; Mon, 14 Dec 2020 22:11:41 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4A3D18D001C; Mon, 14 Dec 2020 22:11:41 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3E5368D0052; Mon, 14 Dec 2020 22:11:41 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0140.hostedemail.com [216.40.44.140]) by kanga.kvack.org (Postfix) with ESMTP id 280C88D001C for ; Mon, 14 Dec 2020 22:11:41 -0500 (EST) Received: from smtpin26.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id E920C2479 for ; Tue, 15 Dec 2020 03:11:40 +0000 (UTC) X-FDA: 77594041560.26.spade20_0d16e1c27420 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin26.hostedemail.com (Postfix) with ESMTP id CC5F11804B660 for ; Tue, 15 Dec 2020 03:11:40 +0000 (UTC) X-HE-Tag: spade20_0d16e1c27420 X-Filterd-Recvd-Size: 6407 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf46.hostedemail.com (Postfix) with ESMTP for ; Tue, 15 Dec 2020 03:11:40 +0000 (UTC) Date: Mon, 14 Dec 2020 19:11:38 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1608001899; bh=E8edMoq1ikhELEaq0Pxaqbl+wR5JtCUaDk7LEIRztYk=; h=From:To:Subject:In-Reply-To:From; b=PoYvYFsSZukSJz6WAT0GRYkJTniC3fzXq23C/oMNSiqH8SJN6IK9E24kVDs5LmUCS 7RuzvTGMxTc3jghq+7L8ARpeaTZo1UdwdDDP2iX6wSdZZxQ69SPKUO67c2RB+GIOOS eKj8gSfVJijLKxh/IZfhUB0jMe1BBXel8MEMcR1E= From: Andrew Morton To: akpm@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, naoya.horiguchi@nec.com, osalvador@suse.de, qcai@redhat.com, torvalds@linux-foundation.org, Vbabka@suse.cz Subject: [patch 141/200] mm,hwpoison: refactor get_any_page Message-ID: <20201215031138.UWpWpFspG%akpm@linux-foundation.org> In-Reply-To: <20201214190237.a17b70ae14f129e2dca3d204@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Oscar Salvador Subject: mm,hwpoison: refactor get_any_page Patch series "HWPoison: Refactor get page interface", v2. This patch (of 3): When we want to grab a refcount via get_any_page, we call __get_any_page that calls get_hwpoison_page to get the actual refcount. get_any_page() is only there because we have a sort of retry mechanism in case the page we met is unknown to us or if we raced with an allocation. Also __get_any_page() prints some messages about the page type in case the page was a free page or the page type was unknown, but if anything, we only need to print a message in case the pagetype was unknown, as that is reporting an error down the chain. Let us merge get_any_page() and __get_any_page(), and let the message be printed in soft_offline_page. While we are it, we can also remove the 'pfn' parameter as it is no longer used. Link: https://lkml.kernel.org/r/20201204102558.31607-1-osalvador@suse.de Link: https://lkml.kernel.org/r/20201204102558.31607-2-osalvador@suse.de Signed-off-by: Oscar Salvador Acked-by: Naoya Horiguchi Acked-by: Vlastimil Babka Cc: Qian Cai Signed-off-by: Andrew Morton --- mm/memory-failure.c | 99 +++++++++++++++++------------------------- 1 file changed, 42 insertions(+), 57 deletions(-) --- a/mm/memory-failure.c~mmhwpoison-refactor-get_any_page +++ a/mm/memory-failure.c @@ -1707,70 +1707,51 @@ EXPORT_SYMBOL(unpoison_memory); /* * Safely get reference count of an arbitrary page. - * Returns 0 for a free page, -EIO for a zero refcount page - * that is not free, and 1 for any other page type. - * For 1 the page is returned with increased page count, otherwise not. + * Returns 0 for a free page, 1 for an in-use page, -EIO for a page-type we + * cannot handle and -EBUSY if we raced with an allocation. + * We only incremented refcount in case the page was already in-use and it is + * a known type we can handle. */ -static int __get_any_page(struct page *p, unsigned long pfn, int flags) +static int get_any_page(struct page *p, int flags) { - int ret; + int ret = 0, pass = 0; + bool count_increased = false; if (flags & MF_COUNT_INCREASED) - return 1; + count_increased = true; - /* - * When the target page is a free hugepage, just remove it - * from free hugepage list. - */ - if (!get_hwpoison_page(p)) { - if (PageHuge(p)) { - pr_info("%s: %#lx free huge page\n", __func__, pfn); - ret = 0; - } else if (is_free_buddy_page(p)) { - pr_info("%s: %#lx free buddy page\n", __func__, pfn); - ret = 0; - } else if (page_count(p)) { - /* raced with allocation */ +try_again: + if (!count_increased && !get_hwpoison_page(p)) { + if (page_count(p)) { + /* We raced with an allocation, retry. */ + if (pass++ < 3) + goto try_again; ret = -EBUSY; - } else { - pr_info("%s: %#lx: unknown zero refcount page type %lx\n", - __func__, pfn, p->flags); + } else if (!PageHuge(p) && !is_free_buddy_page(p)) { + /* We raced with put_page, retry. */ + if (pass++ < 3) + goto try_again; ret = -EIO; } } else { - /* Not a free page */ - ret = 1; - } - return ret; -} - -static int get_any_page(struct page *page, unsigned long pfn, int flags) -{ - int ret = __get_any_page(page, pfn, flags); - - if (ret == -EBUSY) - ret = __get_any_page(page, pfn, flags); - - if (ret == 1 && !PageHuge(page) && - !PageLRU(page) && !__PageMovable(page)) { - /* - * Try to free it. - */ - put_page(page); - shake_page(page, 1); - - /* - * Did it turn free? - */ - ret = __get_any_page(page, pfn, 0); - if (ret == 1 && !PageLRU(page)) { - /* Drop page reference which is from __get_any_page() */ - put_page(page); - pr_info("soft_offline: %#lx: unknown non LRU page type %lx (%pGp)\n", - pfn, page->flags, &page->flags); - return -EIO; + if (PageHuge(p) || PageLRU(p) || __PageMovable(p)) { + ret = 1; + } else { + /* + * A page we cannot handle. Check whether we can turn + * it into something we can handle. + */ + if (pass++ < 3) { + put_page(p); + shake_page(p, 1); + count_increased = false; + goto try_again; + } + put_page(p); + ret = -EIO; } } + return ret; } @@ -1939,7 +1920,7 @@ int soft_offline_page(unsigned long pfn, return -EIO; if (PageHWPoison(page)) { - pr_info("soft offline: %#lx page already poisoned\n", pfn); + pr_info("%s: %#lx page already poisoned\n", __func__, pfn); if (flags & MF_COUNT_INCREASED) put_page(page); return 0; @@ -1947,16 +1928,20 @@ int soft_offline_page(unsigned long pfn, retry: get_online_mems(); - ret = get_any_page(page, pfn, flags); + ret = get_any_page(page, flags); put_online_mems(); - if (ret > 0) + if (ret > 0) { ret = soft_offline_in_use_page(page); - else if (ret == 0) + } else if (ret == 0) { if (soft_offline_free_page(page) && try_again) { try_again = false; goto retry; } + } else if (ret == -EIO) { + pr_info("%s: %#lx: unknown page type: %lx (%pGP)\n", + __func__, pfn, page->flags, &page->flags); + } return ret; }