From patchwork Mon Dec 6 21:22:05 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: andrey.konovalov@linux.dev X-Patchwork-Id: 12694985 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 5C1DFC433F5 for ; Mon, 6 Dec 2021 21:29:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Dm7jCEFMe+dWjwZb/BNbx67wSjTmaO9Pb4HxJzAXkDE=; b=CTaJ5CKty+GaSQ A3M/R+QHpn7iyHqn6TRdjaRT/Chk4DjrmrtwGmzHQy+t9OHfFWYDXYugVOi1TJP5uaL5KhedCVrtt RWnJ9LtguL1hGMmDIlplKOedlqawzaX5y+qtm85KYgB994SHyV95vV7omj+TctmZckB75mmfz548+ HQwvnLq4JJpaK89Urg/jOSZ5Nvx9HHulwn/lHX399iFRZZdlKUL34kp2dcL6DWyme6vu72hBKgFqd n6yuo18xK3c0+z3OhikU2oQHX0cwMosyXDxNx3+K2qESXE6X5oh2Pr8d7ZU+W8vjJvPJNghdJMJqi WI0e4pBD450SZ2x3yUVw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1muLWq-005slS-IE; Mon, 06 Dec 2021 21:28:09 +0000 Received: from out0.migadu.com ([94.23.1.103]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1muLRz-005qda-F8 for linux-arm-kernel@lists.infradead.org; Mon, 06 Dec 2021 21:23:09 +0000 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1638825778; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=4G8h4hgySaJey6iKxW5y4/UhksHPaOzWIIS8r9vmE5w=; b=AfFY/elQmMDAk5i5itHsMNQvHFXdQLT4ic7jzsv8UwzTS0VPaDerdhdSsaTey86OWa8i7v rw9v1VfdGxit77WtIsFyFS/H6ur2KAWsi7W9DNM2EwzygIJnLxpjW3DkIixiYnU1dYKIkx /uM2sicDdMBWIwGV8br6yDwyPIjvt1M= From: andrey.konovalov@linux.dev To: Marco Elver , Alexander Potapenko , Vincenzo Frascino , Catalin Marinas , Peter Collingbourne Cc: Andrey Konovalov , Dmitry Vyukov , Andrey Ryabinin , kasan-dev@googlegroups.com, Andrew Morton , linux-mm@kvack.org, Will Deacon , Mark Rutland , linux-arm-kernel@lists.infradead.org, Evgenii Stepanov , linux-kernel@vger.kernel.org, Andrey Konovalov Subject: [PATCH v2 01/34] kasan, page_alloc: deduplicate should_skip_kasan_poison Date: Mon, 6 Dec 2021 22:22:05 +0100 Message-Id: <9644e588df352734bb5c166caac2d440052cd04f.1638825394.git.andreyknvl@google.com> In-Reply-To: References: MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211206_132307_859502_065EA17A X-CRM114-Status: GOOD ( 15.25 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Andrey Konovalov Currently, should_skip_kasan_poison() has two definitions: one for when CONFIG_DEFERRED_STRUCT_PAGE_INIT is enabled, one for when it's not. Instead of duplicating the checks, add a deferred_pages_enabled() helper and use it in a single should_skip_kasan_poison() definition. Also move should_skip_kasan_poison() closer to its caller and clarify all conditions in the comment. Signed-off-by: Andrey Konovalov --- mm/page_alloc.c | 55 +++++++++++++++++++++++++++++-------------------- 1 file changed, 33 insertions(+), 22 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c5952749ad40..c99566a3b67e 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -375,25 +375,9 @@ int page_group_by_mobility_disabled __read_mostly; */ static DEFINE_STATIC_KEY_TRUE(deferred_pages); -/* - * Calling kasan_poison_pages() only after deferred memory initialization - * has completed. Poisoning pages during deferred memory init will greatly - * lengthen the process and cause problem in large memory systems as the - * deferred pages initialization is done with interrupt disabled. - * - * Assuming that there will be no reference to those newly initialized - * pages before they are ever allocated, this should have no effect on - * KASAN memory tracking as the poison will be properly inserted at page - * allocation time. The only corner case is when pages are allocated by - * on-demand allocation and then freed again before the deferred pages - * initialization is done, but this is not likely to happen. - */ -static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags) +static inline bool deferred_pages_enabled(void) { - return static_branch_unlikely(&deferred_pages) || - (!IS_ENABLED(CONFIG_KASAN_GENERIC) && - (fpi_flags & FPI_SKIP_KASAN_POISON)) || - PageSkipKASanPoison(page); + return static_branch_unlikely(&deferred_pages); } /* Returns true if the struct page for the pfn is uninitialised */ @@ -444,11 +428,9 @@ defer_init(int nid, unsigned long pfn, unsigned long end_pfn) return false; } #else -static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags) +static inline bool deferred_pages_enabled(void) { - return (!IS_ENABLED(CONFIG_KASAN_GENERIC) && - (fpi_flags & FPI_SKIP_KASAN_POISON)) || - PageSkipKASanPoison(page); + return false; } static inline bool early_page_uninitialised(unsigned long pfn) @@ -1258,6 +1240,35 @@ static int free_tail_pages_check(struct page *head_page, struct page *page) return ret; } +/* + * Skip KASAN memory poisoning when either: + * + * 1. Deferred memory initialization has not yet completed, + * see the explanation below. + * 2. Skipping poisoning is requested via FPI_SKIP_KASAN_POISON, + * see the comment next to it. + * 3. Skipping poisoning is requested via __GFP_SKIP_KASAN_POISON, + * see the comment next to it. + * + * Poisoning pages during deferred memory init will greatly lengthen the + * process and cause problem in large memory systems as the deferred pages + * initialization is done with interrupt disabled. + * + * Assuming that there will be no reference to those newly initialized + * pages before they are ever allocated, this should have no effect on + * KASAN memory tracking as the poison will be properly inserted at page + * allocation time. The only corner case is when pages are allocated by + * on-demand allocation and then freed again before the deferred pages + * initialization is done, but this is not likely to happen. + */ +static inline bool should_skip_kasan_poison(struct page *page, fpi_t fpi_flags) +{ + return deferred_pages_enabled() || + (!IS_ENABLED(CONFIG_KASAN_GENERIC) && + (fpi_flags & FPI_SKIP_KASAN_POISON)) || + PageSkipKASanPoison(page); +} + static void kernel_init_free_pages(struct page *page, int numpages, bool zero_tags) { int i;