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 6FA5DCCA47B for ; Mon, 11 Jul 2022 13:35:13 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7A09D6B00E1; Mon, 11 Jul 2022 09:35:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 750996B00E2; Mon, 11 Jul 2022 09:35:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6402A6B00E3; Mon, 11 Jul 2022 09:35:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 562D66B00E1 for ; Mon, 11 Jul 2022 09:35:12 -0400 (EDT) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 2E139608F6 for ; Mon, 11 Jul 2022 13:35:12 +0000 (UTC) X-FDA: 79674915264.17.46805C5 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by imf23.hostedemail.com (Postfix) with ESMTP id 4E4E4140071 for ; Mon, 11 Jul 2022 13:35:10 +0000 (UTC) Received: from dggpemm500024.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4LhPvr4LMyzkWtj; Mon, 11 Jul 2022 21:32:56 +0800 (CST) Received: from dggpemm500001.china.huawei.com (7.185.36.107) by dggpemm500024.china.huawei.com (7.185.36.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 11 Jul 2022 21:35:05 +0800 Received: from [10.174.177.243] (10.174.177.243) by dggpemm500001.china.huawei.com (7.185.36.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 11 Jul 2022 21:35:04 +0800 Message-ID: <13b283fe-10f7-376f-9b8e-856e4d1e0ede@huawei.com> Date: Mon, 11 Jul 2022 21:35:04 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Subject: Re: [PATCH v2 2/4] mm: rmap: Allow platforms without mm_cpumask to defer TLB flush Content-Language: en-US To: Barry Song <21cnbao@gmail.com>, , , , , , , CC: , , , , , , , , , , , , , , , Barry Song References: <20220711034615.482895-1-21cnbao@gmail.com> <20220711034615.482895-3-21cnbao@gmail.com> From: Kefeng Wang In-Reply-To: <20220711034615.482895-3-21cnbao@gmail.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.177.243] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To dggpemm500001.china.huawei.com (7.185.36.107) X-CFilter-Loop: Reflected ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1657546511; 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; bh=Buws9kyZWMrCbcVE/aj1xkDoquvbxVEcEijU3pur/yg=; b=nxet14dXbWjatuLvak9YNYLSsS9I88rpYwfbCLAkkIVOSvLM3frSZGlkRDZawo6Nl/VR53 Wa+IfJuq8WOV2TOjiRVtsdtDGeIhOC0xQmrXgYXsxghI9tPz3Ri3hOFUfez2lAbFAMz9aX G73gp1XwE/f9qYTuXOJkA72eLWI2HGI= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=none; spf=pass (imf23.hostedemail.com: domain of wangkefeng.wang@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=wangkefeng.wang@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1657546511; a=rsa-sha256; cv=none; b=iyix+4ohcT0mWwE6TeUI9NBzNS7TXFTOSAO0TX5igmRUclXWd4ISKYvaFTmmjO3DNOjZ7+ Rm7BFTWPkNZ82kqUUqBfX/apvqMp7HUo8LdRo+5Bs3Xl2iZiBkHY5l4CWVPrfBfNuVj+Fw SGdMRpYD39G2e3C+GAsCR/UfUUJOB9Q= X-Rspamd-Server: rspam02 X-Stat-Signature: uh4k3rmyd9x4jam15ogzanbngoenwdcd X-Rspamd-Queue-Id: 4E4E4140071 X-Rspam-User: Authentication-Results: imf23.hostedemail.com; dkim=none; spf=pass (imf23.hostedemail.com: domain of wangkefeng.wang@huawei.com designates 45.249.212.188 as permitted sender) smtp.mailfrom=wangkefeng.wang@huawei.com; dmarc=pass (policy=quarantine) header.from=huawei.com X-HE-Tag: 1657546510-634790 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: Hi Barry， On 2022/7/11 11:46, Barry Song wrote: > From: Barry Song > > Platforms like ARM64 have hareware TLB shootdown broadcast. They > don't maintain mm_cpumask but just send tlbi and related sync > instructions for TLB flush. task's mm_cpumask is normally empty > in this case. We also allow deferred TLB flush on this kind of > platforms. > > Signed-off-by: Barry Song > > --- ... > diff --git a/mm/Kconfig b/mm/Kconfig > index 169e64192e48..7bf54f57ca01 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -951,6 +951,9 @@ config ARCH_HAS_CURRENT_STACK_POINTER > register alias named "current_stack_pointer", this config can be > selected. > > +config ARCH_HAS_MM_CPUMASK > + bool > + > config ARCH_HAS_VM_GET_PAGE_PROT > bool > > diff --git a/mm/rmap.c b/mm/rmap.c > index 5bcb334cd6f2..13d4f9a1d4f1 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -692,6 +692,10 @@ static bool should_defer_flush(struct mm_struct *mm, enum ttu_flags flags) > if (!(flags & TTU_BATCH_FLUSH)) > return false; > > +#ifndef CONFIG_ARCH_HAS_MM_CPUMASK > + return true; > +#endif > + Here is another option to enable arch's tlbbatch defer [1] https://patchwork.ozlabs.org/project/linuxppc-dev/patch/20171101101735.2318-2-khandual@linux.vnet.ibm.com/ > /* If remote CPUs need to be flushed then defer batch the flush */ > if (cpumask_any_but(mm_cpumask(mm), get_cpu()) < nr_cpu_ids) > should_defer = true;