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 64326C433EF for ; Fri, 8 Jul 2022 15:13:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id ABDAA6B0072; Fri, 8 Jul 2022 11:13:28 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A6DA26B0073; Fri, 8 Jul 2022 11:13:28 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 95BEF6B0074; Fri, 8 Jul 2022 11:13:28 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 82CA56B0072 for ; Fri, 8 Jul 2022 11:13:28 -0400 (EDT) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 59039211A0 for ; Fri, 8 Jul 2022 15:13:28 +0000 (UTC) X-FDA: 79664276496.18.F084551 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by imf19.hostedemail.com (Postfix) with ESMTP id 930C51A004B for ; Fri, 8 Jul 2022 15:13:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1657293206; x=1688829206; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=qigLlHz72omGc2V/B7goHZMXhuZ8SUNrG2eXAMYhtjo=; b=W9rRcHPBjvenkN6ELTn/Mr3hHcOjyEx/1uMHhqzxNjsehRQfeu0Bgfln TlKlyiR5IhzXtgJa89ta4PhmdS+0q51Qype8g5VZXj44+7q3Gs0tOXSKy y/wpSqt/ppUMLa+H0upr/VWGOL53SmPi1sH+JBqxEGXC6Jla7gTQFdIrx ZebdB9m/UTS4AYRolimPX08f10TpWbWuf4P903EcUsjMC1yvriEiKVuJ4 E99tIhdto1y4RbNTQCzSKXWcKMUPdPAZgus8DYy+5f+xeJhVDAIbFRQQ8 8Z0r6wKxXQMjVjcWRbJ+syx3w7rAMdSkkvlC6r+bYT7eSrM1uZCxgdNea A==; X-IronPort-AV: E=McAfee;i="6400,9594,10401"; a="285042432" X-IronPort-AV: E=Sophos;i="5.92,256,1650956400"; d="scan'208";a="285042432" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jul 2022 08:13:25 -0700 X-IronPort-AV: E=Sophos;i="5.92,256,1650956400"; d="scan'208";a="626729479" Received: from yyan2-mobl2.amr.corp.intel.com (HELO [10.212.242.16]) ([10.212.242.16]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jul 2022 08:13:21 -0700 Message-ID: <283d7660-000a-81af-1d6b-4fdedcb6dfd8@intel.com> Date: Fri, 8 Jul 2022 08:13:13 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH] x86/mm/tlb: ignore f->new_tlb_gen when zero Content-Language: en-US To: David Hildenbrand , Nadav Amit , linux-kernel@vger.kernel.org, Hugh Dickins , Thomas Gleixner Cc: Ingo Molnar , Borislav Petkov , x86@kernel.org, Linux MM , Nadav Amit , Dave Hansen , Peter Zijlstra , Andy Lutomirski References: <20220708003053.158480-1-namit@vmware.com> From: Dave Hansen In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1657293207; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=fYOM+K/WHT6L7ViBFvNKQ7FV+n2tHkxHSmH4DHt4GIs=; b=lHNBZBi/aRQZiqkWNIb79xXRqmU+Do2wqsDZ/ab/dXILFUt562t5GuH93dq2VMtekXdMHN Jgpb8uFfLv4d6Zfetf57lyqgm7vAi/lJl3ks0HNaYsFhe7Gul/uW5fepYAyly2eV7kejGr rTWy78M+oSAJ+VR7LSZeM1wb9CbaIrY= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1657293207; a=rsa-sha256; cv=none; b=46sdYFBQbJMpQcOW9iCWYwOnwjmqIGW+FFxtPBpvYvXH8QG8Na/SynFTZHqoe7WhAw579X Hk1VN583RC8bM0Pytlb+OXLtRGhoYQZztD9MqPXYMoCS0NHgd8LQ+7lrZeb9YPEYrO4B/i kWi+TKSPf9FV1tvp6Ht5wuUuO4iz+jg= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=W9rRcHPB; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf19.hostedemail.com: domain of dave.hansen@intel.com has no SPF policy when checking 134.134.136.24) smtp.mailfrom=dave.hansen@intel.com X-Stat-Signature: 83dtbf93oj7npb3qckn5at9fdahud39e X-Rspamd-Queue-Id: 930C51A004B Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=intel.com header.s=Intel header.b=W9rRcHPB; dmarc=pass (policy=none) header.from=intel.com; spf=none (imf19.hostedemail.com: domain of dave.hansen@intel.com has no SPF policy when checking 134.134.136.24) smtp.mailfrom=dave.hansen@intel.com X-Rspam-User: X-Rspamd-Server: rspam05 X-HE-Tag: 1657293206-945649 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: On 7/8/22 04:40, David Hildenbrand wrote: >> diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c >> index d9314cc8b81f..d81b4084bb8a 100644 >> --- a/arch/x86/mm/tlb.c >> +++ b/arch/x86/mm/tlb.c >> @@ -771,14 +771,14 @@ static void flush_tlb_func(void *info) >> return; >> } >> >> - if (f->new_tlb_gen <= local_tlb_gen) { >> + if (unlikely(f->new_tlb_gen != 0 && f->new_tlb_gen <= local_tlb_gen)) { >> /* >> * The TLB is already up to date in respect to f->new_tlb_gen. >> * While the core might be still behind mm_tlb_gen, checking >> * mm_tlb_gen unnecessarily would have negative caching effects >> * so avoid it. >> */ >> - return; >> + goto done; > Does this affect the performance numbers from aa44284960d5 ("x86/mm/tlb: > Avoid reading mm_tlb_gen when possible")? It depends on how many batched flushes that workload had. From the looks of it, they're all one page: madvise(addr + i, pgsize, MADV_DONTNEED); so there shouldn't be *much* batching in play. But, it wouldn't hurt to re-run them in either case.