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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 06843C021AA for ; Wed, 19 Feb 2025 11:21:58 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 806B76B00B1; Wed, 19 Feb 2025 06:21:57 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 7B6A76B00B2; Wed, 19 Feb 2025 06:21:57 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 67DF16B00B7; Wed, 19 Feb 2025 06:21:57 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 48DDA6B00B1 for ; Wed, 19 Feb 2025 06:21:57 -0500 (EST) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id C1A5651759 for ; Wed, 19 Feb 2025 11:21:56 +0000 (UTC) X-FDA: 83136454632.17.05A129E Received: from mail.alien8.de (mail.alien8.de [65.109.113.108]) by imf18.hostedemail.com (Postfix) with ESMTP id ACD461C0007 for ; Wed, 19 Feb 2025 11:21:54 +0000 (UTC) Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=alien8.de header.s=alien8 header.b=NEzVym+W; dmarc=pass (policy=none) header.from=alien8.de; spf=pass (imf18.hostedemail.com: domain of bp@alien8.de designates 65.109.113.108 as permitted sender) smtp.mailfrom=bp@alien8.de ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1739964115; a=rsa-sha256; cv=none; b=E/2xXSOSJ92uk4Ep+8FRdIrwBU9zrHsUdc5owKFmrIGKyvclKSLBY5Wq0lEhQ44C37q66W 0PiO5DKRkIpjTHJ1wUrd0uiKMcuzXWFQofy18oj7zEFtJkunvDlW9YufqldB5lkebl6J/X IrNSEATybiGYUUc8gFefUugmxLcQyt4= ARC-Authentication-Results: i=1; imf18.hostedemail.com; dkim=pass header.d=alien8.de header.s=alien8 header.b=NEzVym+W; dmarc=pass (policy=none) header.from=alien8.de; spf=pass (imf18.hostedemail.com: domain of bp@alien8.de designates 65.109.113.108 as permitted sender) smtp.mailfrom=bp@alien8.de ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1739964115; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=eTUjwt5//DA+LtwykcARc8xiBAvEsEq/rmX8J9I+2jA=; b=rEyygGtcOvPgjDDSG2tk3G6J+tWvUORnvCwA2R8aeGqIIjG3KL0vfxUDsUXNK2F8vqLRG+ z4USU7Iem7fIx7Z2ZSEdcs/12SxhsDfkkjJ/u464F53FrXOS2PPFwCOStEWZFafeCl2xIE Pk6As7xQhuKVZYcdTMGp1l5SGe7b6+8= Received: from localhost (localhost.localdomain [127.0.0.1]) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTP id A50A840E0221; Wed, 19 Feb 2025 11:21:50 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mail.alien8.de Received: from mail.alien8.de ([127.0.0.1]) by localhost (mail.alien8.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id JQqlS3ylZ2JE; Wed, 19 Feb 2025 11:21:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=alien8; t=1739964105; bh=eTUjwt5//DA+LtwykcARc8xiBAvEsEq/rmX8J9I+2jA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=NEzVym+Wqml9nKrSyHOg0USrV+lln8p6KXwRZXlGOD+fD06ZYGHMy7xJXVMBhWhrf LH4zjdP1dgoQeBx4j2CzCC2kty6OIiQJsRo0NIIgfIiWhQiXgcK/J4o4t97uJUdw+O cjSv5iX7F3Ech98+B8qeUcN+Wp0jvlt/uwf58SOmnsl8sPnrQWQQkZltWkYHI+T0GZ 1rEnP5iNhF9JA08X3NhLVD9YxMtX9c6rXDmVB/gzXoVwyD2otZHhJ+b6811+wKMbZG HK1YbaRh0+VIPJva36Al9ObTGLw7WpaK1+IAzpaW/Ari/DVhRx6bhzcoToquS1e9mB GHJjUTTIUTzk5h7o1QF2vPBKW7Fn5WP25OhMvC1xl+pllxI3HtyD7U6D4ebA3qYgBW w8uhfZtl3TBj5ctTR+HIdSSLHiSU0q3HKwLEYmBxyi8jZMc69HvXhatcHlif7OqaM2 fTwuUkvCPwq9VUxdmsRPTr9YLBOWti0O0kZR7HFh5mImzVKoCITpDMBxuuZwU2Iedq Zp/9wCj85JskDDZIT8B+7tv6PzuWxr804ANGMmTPdyVXr/DbZHAdtqH02k1YvCXINo U3Orryzmvt7bKgIe/ohxIEPVm89C3oOUSAsOmr4k9dhH8y+EPcAzwWgurwoOPDYqRk eO7SaKuAvscarQMzSzuWW4Sg= Received: from zn.tnic (pd95303ce.dip0.t-ipconnect.de [217.83.3.206]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature ECDSA (P-256) server-digest SHA256) (No client certificate requested) by mail.alien8.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 3297C40E01B2; Wed, 19 Feb 2025 11:21:29 +0000 (UTC) Date: Wed, 19 Feb 2025 12:21:22 +0100 From: Borislav Petkov To: Rik van Riel Cc: x86@kernel.org, linux-kernel@vger.kernel.org, peterz@infradead.org, dave.hansen@linux.intel.com, zhengqi.arch@bytedance.com, nadav.amit@gmail.com, thomas.lendacky@amd.com, kernel-team@meta.com, linux-mm@kvack.org, akpm@linux-foundation.org, jackmanb@google.com, jannh@google.com, mhklinux@outlook.com, andrew.cooper3@citrix.com, Dave Hansen Subject: Re: [PATCH v11 03/12] x86/mm: consolidate full flush threshold decision Message-ID: <20250219112122.GLZ7W-sjOTi-LXlRp4@fat_crate.local> References: <20250213161423.449435-1-riel@surriel.com> <20250213161423.449435-4-riel@surriel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250213161423.449435-4-riel@surriel.com> X-Rspam-User: X-Rspamd-Queue-Id: ACD461C0007 X-Rspamd-Server: rspam12 X-Stat-Signature: q6r7yqxsz9ssgkanyxoxxtnu46qfpgij X-HE-Tag: 1739964114-190859 X-HE-Meta: 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 cFi0PUm/ hqWVB1PltNHv5JW6dIJ7dEpH3rmWwdRH20zAFx21QhCMsPkBQDt8gLdH5FiTaFygC0tNx6mSnqLJ/1eo+YdGj5qwHkM/89vFEviJ6zKo0OZXV0frOxaB7sKKMRqvK7H4KHly2fqDndtHy06AedybXsCX9OoC5vCsLYTkpxwJLK7amvrtPEzGOBSd5BAdkL58f39/guHvoupmb3A3pixEKqg1pP1/YywEm+sALOCPk9J29MfWDC25L7OS31TRjI3qYmjRh4MGfEnD5EkAwB4ks+o4wnB+CoQctzFYyplrBS0JS7TZHZoeiIALg05fCnb4zkNdSB34ouEndZdvzX32tpRtl1A== 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: List-Subscribe: List-Unsubscribe: On Thu, Feb 13, 2025 at 11:13:54AM -0500, Rik van Riel wrote: > @@ -1009,6 +1009,15 @@ static struct flush_tlb_info *get_flush_tlb_info(struct mm_struct *mm, > info->initiating_cpu = smp_processor_id(); > info->trim_cpumask = 0; > > + /* > + * If the number of flushes is so large that a full flush > + * would be faster, do a full flush. > + */ > + if ((end - start) >> stride_shift > tlb_single_page_flush_ceiling) { > + info->start = 0; > + info->end = TLB_FLUSH_ALL; > + } And if you move the range decision before the info-> struct members assignment, it becomes even more readable because you're using start and end in the check and then you assign it so a reader doesn't have to go and look whether start and end are the same as info->start and info->end: /* * If the number of flushes is so large that a full flush * would be faster, do a full flush. */ if ((end - start) >> stride_shift > tlb_single_page_flush_ceiling) { start = 0; end = TLB_FLUSH_ALL; } info->start = start; info->end = end; info->mm = mm; info->stride_shift = stride_shift; info->freed_tables = freed_tables; info->new_tlb_gen = new_tlb_gen; info->initiating_cpu = smp_processor_id(); info->trim_cpumask = 0; return info; } with that: Reviewed-by: Borislav Petkov (AMD) -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette