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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4C329C433F5 for ; Thu, 12 May 2022 16:55:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1356721AbiELQzB (ORCPT ); Thu, 12 May 2022 12:55:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33356 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356729AbiELQy4 (ORCPT ); Thu, 12 May 2022 12:54:56 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6CA24268E81 for ; Thu, 12 May 2022 09:54:53 -0700 (PDT) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1652374491; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=g9OGQXFAdNRLEL0zQyUEGtTMfeAi/qDPt3Ou0IhrCyA=; b=humB9ohVLnjzd2kRNuT8ycEQB3h9tIwwGsvI43HGZ7uU6RozFrxyYg0LzVFMYJVPRxemDl Ax2c+QiMKrTeCoFHAkPPMYky92ENjr78VTxLzu1SFlARzpp+bSeUssVIf2a7g5YjUtLHNy 9cq8hLK/PbUMUhrtsKxHCp2JGxd74ObXPOzvn2quAiUtEEDXdtSaUX+PmpNdKAu/xLaJ5H y63d0n1T0NW+M888d0zM1EYDXHpUQ914DuUvzzgOjf1AOcm4J+FbGIMZbBzhu9du3wSVEO 29tS+6CWbeAQLfOYSiNqN8QSTxza49pYwwPJr/AxeIrPQOJXCxQusoJgruh5JA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1652374491; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=g9OGQXFAdNRLEL0zQyUEGtTMfeAi/qDPt3Ou0IhrCyA=; b=GEeW32UrEoUxxZjjq6f1C6V9X3+MVLoiOcoOUqpXdmbWLD6TYJMYNiexOlmlUi4rIiuvF8 AasoTkPkiZS3unCg== To: David Hildenbrand , Adrian-Ken Rueegsegger , dave.hansen@linux.intel.com, osalvador@suse.de Cc: luto@kernel.org, peterz@infradead.org, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86/mm: Fix marking of unused sub-pmd ranges In-Reply-To: <8f2af450-1080-2dcd-9c85-6190e7e14f27@redhat.com> References: <20220509090637.24152-1-ken@codelabs.ch> <20220509090637.24152-2-ken@codelabs.ch> <8f2af450-1080-2dcd-9c85-6190e7e14f27@redhat.com> Date: Thu, 12 May 2022 18:54:50 +0200 Message-ID: <87bkw2vgh1.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, May 12 2022 at 11:04, David Hildenbrand wrote: > On 09.05.22 11:06, Adrian-Ken Rueegsegger wrote: >> static void __meminit vmemmap_use_new_sub_pmd(unsigned long start, unsigned long end) >> { >> + const unsigned long page = ALIGN_DOWN(start, PMD_SIZE); >> + >> vmemmap_flush_unused_pmd(); >> >> /* >> @@ -914,8 +916,7 @@ static void __meminit vmemmap_use_new_sub_pmd(unsigned long start, unsigned long >> * Mark with PAGE_UNUSED the unused parts of the new memmap range >> */ >> if (!IS_ALIGNED(start, PMD_SIZE)) >> - memset((void *)start, PAGE_UNUSED, >> - start - ALIGN_DOWN(start, PMD_SIZE)); >> + memset((void *)page, PAGE_UNUSED, start - page); >> >> /* >> * We want to avoid memset(PAGE_UNUSED) when populating the vmemmap of > > As the x86 code was based on my s390x code, I assume that this was > accidentally introduced in the x86 variant. > > We'd be marking the wrong range PAGE_UNUSED. > > Your fix looks correct to me: > > Reviewed-by: David Hildenbrand > > Do we want to cc stable? Yes, we'll add it when picking it up. I really have to ask why this duplicated code exists in the first place. There is zero architecture specific code neither in the s390 nor in the x86 version. The x86 version is just copy & pasta & fatfinger, if I'm not missing something here. Thanks, tglx