From patchwork Fri Apr 1 23:08:03 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zi Yan X-Patchwork-Id: 12798841 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id D03B3C433EF for ; Fri, 1 Apr 2022 23:08:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1ABCA8D0001; Fri, 1 Apr 2022 19:08:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1409A6B0072; Fri, 1 Apr 2022 19:08:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ECAF58D0001; Fri, 1 Apr 2022 19:08:20 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.a.hostedemail.com [64.99.140.24]) by kanga.kvack.org (Postfix) with ESMTP id DAE6E6B0071 for ; Fri, 1 Apr 2022 19:08:20 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id A11C825111 for ; Fri, 1 Apr 2022 23:08:10 +0000 (UTC) X-FDA: 79309850340.14.62860E8 Received: from out2-smtp.messagingengine.com (out2-smtp.messagingengine.com [66.111.4.26]) by imf17.hostedemail.com (Postfix) with ESMTP id ED5564000A for ; Fri, 1 Apr 2022 23:08:09 +0000 (UTC) Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.nyi.internal (Postfix) with ESMTP id 85B365C01C6; Fri, 1 Apr 2022 19:08:09 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute5.internal (MEProxy); Fri, 01 Apr 2022 19:08:09 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sent.com; h=cc :cc:content-transfer-encoding:date:date:from:from:in-reply-to :message-id:mime-version:reply-to:reply-to:sender:subject :subject:to:to; s=fm3; bh=n7TcKvtoCX05FSZFqOIqh4H/JQJNmNodokE+bj ntX2M=; b=VDAVqSyUvErOuKXGvLhBqj13vFM2Pu/M1VOx9zjzs/ak8FGTQAfhp3 XHIx4YEMxM5OjOhpwoWgkRIcROFUX/2JdGlAVVbgO5df2e41NkxKTJf5Dfe09ot5 0LVTmNpQUnOVZG1QU5Lg95T+7PU2GEfuf4TaR8uehV8FPLTvGQpcoYgpbtSm4IJ2 MxPjOcusxCKHstCEviiRoy/VtLEtXhu2v0FIsHq8GNNdK8mwJnJ+lCewNxfHZMUR NxQN47E0ZLekzArjh44gUEr8fKqqSX1VgYQuHjFMcU3lD+MP4ZWT0zWCA0BRaU/M AXHyaNs3aYX7IMDAFzZm2YXUJlEEshHw== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding:date:date :from:from:in-reply-to:message-id:mime-version:reply-to:reply-to :sender:subject:subject:to:to:x-me-proxy:x-me-proxy:x-me-sender :x-me-sender:x-sasl-enc; s=fm3; bh=n7TcKvtoCX05FSZFqOIqh4H/JQJNm NodokE+bjntX2M=; b=J3Dav6ap+XnWqah7nTw20jx+92by9t7q8rNPlP0FT3s1Y uk0UFFuQLEPxldHXdl6CMMn5b9Ivl70xM/rrPV8RcuZHuhbx5ljBN27rlddUa8R0 U/CAlDwgV10LoYT/AuA2dp3+TN4tYqkGm0C/7bqKLwKoy/OlDyCQeByoXBO83Gel nV1HXp292OM0PkC5FXPRSSAo0hYmGL5EjswNb4OGowKDCvQD082Da6x0DRJGMpN2 dWRICq249llCECQWTvdKzNDgPdhgj0zFalj1nvtXn6LxsXxcj64ZQBC/ku+6S2iN lMXJB/KV1WMKlcbHucO8VNsg1uvy+HeFMK43/iiOQ== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvvddrudeijedgudduucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhephffvufffkfforhgggfestdhqredtredttdenucfhrhhomhepkghiucgjrghn uceoiihirdihrghnsehsvghnthdrtghomheqnecuggftrfgrthhtvghrnhepteeiiedtje fghfefueekjedvueeftddvudelhfetudffiefgfeetheeghfdvgedunecuffhomhgrihhn pehkvghrnhgvlhdrohhrghenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepmh grihhlfhhrohhmpeiiihdrhigrnhesshgvnhhtrdgtohhm X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 1 Apr 2022 19:08:08 -0400 (EDT) From: Zi Yan To: linux-mm@kvack.org Cc: Linus Torvalds , Steven Rostedt , David Hildenbrand , Vlastimil Babka , Mel Gorman , Mike Rapoport , Oscar Salvador , Andrew Morton , linux-kernel@vger.kernel.org, Zi Yan Subject: [PATCH v3 1/2] mm: page_alloc: simplify pageblock migratetype check in __free_one_page(). Date: Fri, 1 Apr 2022 19:08:03 -0400 Message-Id: <20220401230804.1658207-1-zi.yan@sent.com> X-Mailer: git-send-email 2.35.1 Reply-To: Zi Yan MIME-Version: 1.0 Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=sent.com header.s=fm3 header.b=VDAVqSyU; dkim=pass header.d=messagingengine.com header.s=fm3 header.b=J3Dav6ap; spf=pass (imf17.hostedemail.com: domain of zi.yan@sent.com designates 66.111.4.26 as permitted sender) smtp.mailfrom=zi.yan@sent.com; dmarc=pass (policy=none) header.from=sent.com X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: ED5564000A X-Stat-Signature: qdg7usnnf56y8m8gsguwdpf9ozbcrfjw X-HE-Tag: 1648854489-912690 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: Zi Yan Move pageblock migratetype check code in the while loop to simplify the logic. It also saves redundant buddy page checking code. Suggested-by: Vlastimil Babka Link: https://lore.kernel.org/linux-mm/27ff69f9-60c5-9e59-feb2-295250077551@suse.cz/ Signed-off-by: Zi Yan Acked-by: Vlastimil Babka --- mm/page_alloc.c | 46 +++++++++++++++++----------------------------- 1 file changed, 17 insertions(+), 29 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 856473e54155..2ea106146686 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1054,7 +1054,6 @@ static inline void __free_one_page(struct page *page, int migratetype, fpi_t fpi_flags) { struct capture_control *capc = task_capc(zone); - unsigned int max_order = pageblock_order; unsigned long buddy_pfn; unsigned long combined_pfn; struct page *buddy; @@ -1070,8 +1069,7 @@ static inline void __free_one_page(struct page *page, VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page); VM_BUG_ON_PAGE(bad_range(zone, page), page); -continue_merging: - while (order < max_order) { + while (order < MAX_ORDER - 1) { if (compaction_capture(capc, page, order, migratetype)) { __mod_zone_freepage_state(zone, -(1 << order), migratetype); @@ -1082,6 +1080,22 @@ static inline void __free_one_page(struct page *page, if (!page_is_buddy(page, buddy, order)) goto done_merging; + + if (unlikely(order >= pageblock_order)) { + /* + * We want to prevent merge between freepages on pageblock + * without fallbacks and normal pageblock. Without this, + * pageblock isolation could cause incorrect freepage or CMA + * accounting or HIGHATOMIC accounting. + */ + int buddy_mt = get_pageblock_migratetype(buddy); + + if (migratetype != buddy_mt + && (!migratetype_is_mergeable(migratetype) || + !migratetype_is_mergeable(buddy_mt))) + goto done_merging; + } + /* * Our buddy is free or it is CONFIG_DEBUG_PAGEALLOC guard page, * merge with it and move up one order. @@ -1095,32 +1109,6 @@ static inline void __free_one_page(struct page *page, pfn = combined_pfn; order++; } - if (order < MAX_ORDER - 1) { - /* If we are here, it means order is >= pageblock_order. - * We want to prevent merge between freepages on pageblock - * without fallbacks and normal pageblock. Without this, - * pageblock isolation could cause incorrect freepage or CMA - * accounting or HIGHATOMIC accounting. - * - * We don't want to hit this code for the more frequent - * low-order merging. - */ - int buddy_mt; - - buddy_pfn = __find_buddy_pfn(pfn, order); - buddy = page + (buddy_pfn - pfn); - - if (!page_is_buddy(page, buddy, order)) - goto done_merging; - buddy_mt = get_pageblock_migratetype(buddy); - - if (migratetype != buddy_mt - && (!migratetype_is_mergeable(migratetype) || - !migratetype_is_mergeable(buddy_mt))) - goto done_merging; - max_order = order + 1; - goto continue_merging; - } done_merging: set_buddy_order(page, order); From patchwork Fri Apr 1 23:08:04 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zi Yan X-Patchwork-Id: 12798842 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id DB102C433F5 for ; Fri, 1 Apr 2022 23:08:48 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 753218D0002; Fri, 1 Apr 2022 19:08:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 700E16B0072; Fri, 1 Apr 2022 19:08:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 52C468D0002; Fri, 1 Apr 2022 19:08:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0126.hostedemail.com [216.40.44.126]) by kanga.kvack.org (Postfix) with ESMTP id 426E56B0071 for ; Fri, 1 Apr 2022 19:08:21 -0400 (EDT) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id E1C158281E1A for ; Fri, 1 Apr 2022 23:08:10 +0000 (UTC) X-FDA: 79309850340.21.98C8BC9 Received: from out2-smtp.messagingengine.com (out2-smtp.messagingengine.com [66.111.4.26]) by imf30.hostedemail.com (Postfix) with ESMTP id 5BC418001A for ; Fri, 1 Apr 2022 23:08:10 +0000 (UTC) Received: from compute5.internal (compute5.nyi.internal [10.202.2.45]) by mailout.nyi.internal (Postfix) with ESMTP id 0AB635C01A4; Fri, 1 Apr 2022 19:08:10 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute5.internal (MEProxy); Fri, 01 Apr 2022 19:08:10 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sent.com; h=cc :cc:content-transfer-encoding:date:date:from:from:in-reply-to :in-reply-to:message-id:mime-version:references:reply-to :reply-to:sender:subject:subject:to:to; s=fm3; bh=sY3p/Hs4wasZBU gKGBvaUDfyN3fVA73veu73/gqoqQo=; b=ogM2whPW4uA/6DeP2LN+WjgLQg8rQr ssNzk6Nj8zl+RqWiq4vJ1UkthzMAXY7FO8/gTleuMOviNGlXlHuOZJlO1vJg1NHq g7yU8KuCfCey9VJZm0RaKrMJCK32C844j3zfKtq+TEtjgQKYp97s21Cv803ehW2/ c1l27mbX2FCROnC7sOryaJlUVd5geg3c6NF5gItreAEIKDBdylX45EMRdBBc24EJ 1wnW5BzXYGc9I8fvBAZvGjdiPpsyYH7e0VYE10NTIARdV/iaB5g8GERwVqg3NaSm KEbLN8VgfIfSFrLuh2A3Ly0Uy/fbMIv4u2nJ7GnRVIfY9kzocFWoGiYA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-transfer-encoding:date:date :from:from:in-reply-to:in-reply-to:message-id:mime-version :references:reply-to:reply-to:sender:subject:subject:to:to :x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm3; bh=sY3p/Hs4wasZBUgKGBvaUDfyN3fVA73veu73/gqoqQo=; b=Zt3RWstc rBo8qzxFzEjdM4JrOGzJEm3tWNxbmueSu5LZTNvHu6CU9cY4Wo9tItz7ED3M3QvP HcSvcDdvrtlApTP9ClbCspbbcksYjkObUQo43cTV5ODkL1iSOmLPgqxeqq1Due5m s1ebzQWTY3WgIGzqHV/sZfYs7O3BjArqyiMPAdtn16UUiF4gwtjr68vOJdRQYjFs X/Zwz+KMVSv0yfEl5uG4dEn4KMXRKQYTtKfrXkRccT3WiPs6AK4ph0zVc0gSu4lb +9P4HaYR3go+jPLM1LWxeODVkJl8ByU6tGoJeF1oa6R8GC+Xs+r6W8Bg8y469GFO SHCOY/wwi+mRmw== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgedvvddrudeijedgudduucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmne cujfgurhephffvufffkffojghfrhgggfestdhqredtredttdenucfhrhhomhepkghiucgj rghnuceoiihirdihrghnsehsvghnthdrtghomheqnecuggftrfgrthhtvghrnhepkeeiue elvddtteeujeehtdegheejledvtdetgfeileejfeeghfeftdeuffefleevnecuffhomhgr ihhnpehkvghrnhgvlhdrohhrghenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmh epmhgrihhlfhhrohhmpeiiihdrhigrnhesshgvnhhtrdgtohhm X-ME-Proxy: Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 1 Apr 2022 19:08:09 -0400 (EDT) From: Zi Yan To: linux-mm@kvack.org Cc: Linus Torvalds , Steven Rostedt , David Hildenbrand , Vlastimil Babka , Mel Gorman , Mike Rapoport , Oscar Salvador , Andrew Morton , linux-kernel@vger.kernel.org, Zi Yan Subject: [PATCH v3 2/2] mm: wrap __find_buddy_pfn() with a necessary buddy page validation. Date: Fri, 1 Apr 2022 19:08:04 -0400 Message-Id: <20220401230804.1658207-2-zi.yan@sent.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220401230804.1658207-1-zi.yan@sent.com> References: <20220401230804.1658207-1-zi.yan@sent.com> Reply-To: Zi Yan MIME-Version: 1.0 X-Stat-Signature: rmokwjm96oaa9qfkaoofxb1ao4yjyrxe Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=sent.com header.s=fm3 header.b=ogM2whPW; dkim=pass header.d=messagingengine.com header.s=fm3 header.b=Zt3RWstc; spf=pass (imf30.hostedemail.com: domain of zi.yan@sent.com designates 66.111.4.26 as permitted sender) smtp.mailfrom=zi.yan@sent.com; dmarc=pass (policy=none) header.from=sent.com X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 5BC418001A X-HE-Tag: 1648854490-165132 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: Zi Yan Whenever the buddy of a page is found from __find_buddy_pfn(), page_is_buddy() should be used to check its validity. Add a helper function find_buddy_page_pfn() to find the buddy page and do the check together. Suggested-by: Linus Torvalds Link: https://lore.kernel.org/linux-mm/CAHk-=wji_AmYygZMTsPMdJ7XksMt7kOur8oDfDdniBRMjm4VkQ@mail.gmail.com/ Signed-off-by: Zi Yan Acked-by: Vlastimil Babka --- mm/internal.h | 117 ++++++++++++++++++++++++++++++++++---------- mm/page_alloc.c | 52 +++----------------- mm/page_isolation.c | 9 ++-- 3 files changed, 101 insertions(+), 77 deletions(-) diff --git a/mm/internal.h b/mm/internal.h index 876e66237c89..56bbae014e0e 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -211,6 +211,67 @@ struct alloc_context { bool spread_dirty_pages; }; +/* + * This function returns the order of a free page in the buddy system. In + * general, page_zone(page)->lock must be held by the caller to prevent the + * page from being allocated in parallel and returning garbage as the order. + * If a caller does not hold page_zone(page)->lock, it must guarantee that the + * page cannot be allocated or merged in parallel. Alternatively, it must + * handle invalid values gracefully, and use buddy_order_unsafe() below. + */ +static inline unsigned int buddy_order(struct page *page) +{ + /* PageBuddy() must be checked by the caller */ + return page_private(page); +} + +/* + * Like buddy_order(), but for callers who cannot afford to hold the zone lock. + * PageBuddy() should be checked first by the caller to minimize race window, + * and invalid values must be handled gracefully. + * + * READ_ONCE is used so that if the caller assigns the result into a local + * variable and e.g. tests it for valid range before using, the compiler cannot + * decide to remove the variable and inline the page_private(page) multiple + * times, potentially observing different values in the tests and the actual + * use of the result. + */ +#define buddy_order_unsafe(page) READ_ONCE(page_private(page)) + +/* + * This function checks whether a page is free && is the buddy + * we can coalesce a page and its buddy if + * (a) the buddy is not in a hole (check before calling!) && + * (b) the buddy is in the buddy system && + * (c) a page and its buddy have the same order && + * (d) a page and its buddy are in the same zone. + * + * For recording whether a page is in the buddy system, we set PageBuddy. + * Setting, clearing, and testing PageBuddy is serialized by zone->lock. + * + * For recording page's order, we use page_private(page). + */ +static inline bool page_is_buddy(struct page *page, struct page *buddy, + unsigned int order) +{ + if (!page_is_guard(buddy) && !PageBuddy(buddy)) + return false; + + if (buddy_order(buddy) != order) + return false; + + /* + * zone check is done late to avoid uselessly calculating + * zone/node ids for pages that could never merge. + */ + if (page_zone_id(page) != page_zone_id(buddy)) + return false; + + VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy); + + return true; +} + /* * Locate the struct page for both the matching buddy in our * pair (buddy1) and the combined O(n+1) page they form (page). @@ -234,6 +295,35 @@ __find_buddy_pfn(unsigned long page_pfn, unsigned int order) return page_pfn ^ (1 << order); } +/* + * Find the buddy of @page and validate it. + * @page: The input page + * @pfn: The pfn of the page, it saves a call to page_to_pfn() when the + * function is used in the performance-critical __free_one_page(). + * @order: The order of the page + * @buddy_pfn: The output pointer to the buddy pfn, it also saves a call to + * page_to_pfn(). + * + * The found buddy can be a non PageBuddy, out of @page's zone, or its order is + * not the same as @page. The validation is necessary before use it. + * + * Return: the found buddy page or NULL if not found. + */ +static inline struct page *find_buddy_page_pfn(struct page *page, + unsigned long pfn, unsigned int order, unsigned long *buddy_pfn) +{ + struct page *buddy; + unsigned long __buddy_pfn = __find_buddy_pfn(pfn, order); + + buddy = page + (__buddy_pfn - pfn); + if (buddy_pfn) + *buddy_pfn = __buddy_pfn; + + if (page_is_buddy(page, buddy, order)) + return buddy; + return NULL; +} + extern struct page *__pageblock_pfn_to_page(unsigned long start_pfn, unsigned long end_pfn, struct zone *zone); @@ -336,33 +426,6 @@ isolate_migratepages_range(struct compact_control *cc, int find_suitable_fallback(struct free_area *area, unsigned int order, int migratetype, bool only_stealable, bool *can_steal); -/* - * This function returns the order of a free page in the buddy system. In - * general, page_zone(page)->lock must be held by the caller to prevent the - * page from being allocated in parallel and returning garbage as the order. - * If a caller does not hold page_zone(page)->lock, it must guarantee that the - * page cannot be allocated or merged in parallel. Alternatively, it must - * handle invalid values gracefully, and use buddy_order_unsafe() below. - */ -static inline unsigned int buddy_order(struct page *page) -{ - /* PageBuddy() must be checked by the caller */ - return page_private(page); -} - -/* - * Like buddy_order(), but for callers who cannot afford to hold the zone lock. - * PageBuddy() should be checked first by the caller to minimize race window, - * and invalid values must be handled gracefully. - * - * READ_ONCE is used so that if the caller assigns the result into a local - * variable and e.g. tests it for valid range before using, the compiler cannot - * decide to remove the variable and inline the page_private(page) multiple - * times, potentially observing different values in the tests and the actual - * use of the result. - */ -#define buddy_order_unsafe(page) READ_ONCE(page_private(page)) - /* * These three helpers classifies VMAs for virtual memory accounting. */ diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 2ea106146686..b08eecd67aba 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -868,40 +868,6 @@ static inline void set_buddy_order(struct page *page, unsigned int order) __SetPageBuddy(page); } -/* - * This function checks whether a page is free && is the buddy - * we can coalesce a page and its buddy if - * (a) the buddy is not in a hole (check before calling!) && - * (b) the buddy is in the buddy system && - * (c) a page and its buddy have the same order && - * (d) a page and its buddy are in the same zone. - * - * For recording whether a page is in the buddy system, we set PageBuddy. - * Setting, clearing, and testing PageBuddy is serialized by zone->lock. - * - * For recording page's order, we use page_private(page). - */ -static inline bool page_is_buddy(struct page *page, struct page *buddy, - unsigned int order) -{ - if (!page_is_guard(buddy) && !PageBuddy(buddy)) - return false; - - if (buddy_order(buddy) != order) - return false; - - /* - * zone check is done late to avoid uselessly calculating - * zone/node ids for pages that could never merge. - */ - if (page_zone_id(page) != page_zone_id(buddy)) - return false; - - VM_BUG_ON_PAGE(page_count(buddy) != 0, buddy); - - return true; -} - #ifdef CONFIG_COMPACTION static inline struct capture_control *task_capc(struct zone *zone) { @@ -1010,18 +976,17 @@ static inline bool buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn, struct page *page, unsigned int order) { - struct page *higher_page, *higher_buddy; - unsigned long combined_pfn; + struct page *higher_page; + unsigned long higher_page_pfn; if (order >= MAX_ORDER - 2) return false; - combined_pfn = buddy_pfn & pfn; - higher_page = page + (combined_pfn - pfn); - buddy_pfn = __find_buddy_pfn(combined_pfn, order + 1); - higher_buddy = higher_page + (buddy_pfn - combined_pfn); + higher_page_pfn = buddy_pfn & pfn; + higher_page = page + (higher_page_pfn - pfn); - return page_is_buddy(higher_page, higher_buddy, order + 1); + return find_buddy_page_pfn(higher_page, higher_page_pfn, order + 1, + NULL) != NULL; } /* @@ -1075,10 +1040,9 @@ static inline void __free_one_page(struct page *page, migratetype); return; } - buddy_pfn = __find_buddy_pfn(pfn, order); - buddy = page + (buddy_pfn - pfn); - if (!page_is_buddy(page, buddy, order)) + buddy = find_buddy_page_pfn(page, pfn, order, &buddy_pfn); + if (!buddy) goto done_merging; if (unlikely(order >= pageblock_order)) { diff --git a/mm/page_isolation.c b/mm/page_isolation.c index f67c4c70f17f..ff0ea6308299 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -70,7 +70,6 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype) unsigned long flags, nr_pages; bool isolated_page = false; unsigned int order; - unsigned long pfn, buddy_pfn; struct page *buddy; zone = page_zone(page); @@ -89,11 +88,9 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype) if (PageBuddy(page)) { order = buddy_order(page); if (order >= pageblock_order && order < MAX_ORDER - 1) { - pfn = page_to_pfn(page); - buddy_pfn = __find_buddy_pfn(pfn, order); - buddy = page + (buddy_pfn - pfn); - - if (!is_migrate_isolate_page(buddy)) { + buddy = find_buddy_page_pfn(page, page_to_pfn(page), + order, NULL); + if (buddy && !is_migrate_isolate_page(buddy)) { isolated_page = !!__isolate_free_page(page, order); /* * Isolating a free page in an isolated pageblock