From patchwork Mon Aug 22 08:21:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yicong Yang X-Patchwork-Id: 12950322 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 B1249C32789 for ; Mon, 22 Aug 2022 08:23:36 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BB32D6B0073; Mon, 22 Aug 2022 04:23:35 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B3B468D0001; Mon, 22 Aug 2022 04:23:35 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9DB336B0075; Mon, 22 Aug 2022 04:23:35 -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 895E76B0073 for ; Mon, 22 Aug 2022 04:23:35 -0400 (EDT) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 6163240846 for ; Mon, 22 Aug 2022 08:23:35 +0000 (UTC) X-FDA: 79826539590.11.C58B576 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by imf07.hostedemail.com (Postfix) with ESMTP id 4774340044 for ; Mon, 22 Aug 2022 08:23:34 +0000 (UTC) Received: from canpemm500009.china.huawei.com (unknown [172.30.72.56]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4MB50n281BznTgN; Mon, 22 Aug 2022 16:21:13 +0800 (CST) Received: from localhost.localdomain (10.67.164.66) by canpemm500009.china.huawei.com (7.192.105.203) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 22 Aug 2022 16:23:29 +0800 From: Yicong Yang To: , , , , , , CC: , , , , , , , , , , , , , , , , Barry Song <21cnbao@gmail.com>, , , , Subject: [PATCH v3 0/4] mm: arm64: bring up BATCHED_UNMAP_TLB_FLUSH Date: Mon, 22 Aug 2022 16:21:16 +0800 Message-ID: <20220822082120.8347-1-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 MIME-Version: 1.0 X-Originating-IP: [10.67.164.66] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To canpemm500009.china.huawei.com (7.192.105.203) X-CFilter-Loop: Reflected ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1661156615; a=rsa-sha256; cv=none; b=HZwP00bLQ/+ZXBCENdvqw7QTAKWo+he19mopMoHhl57JsNvZKXiADxpx92Xao7IQ/9E0Xg sGC9ef9Qf3u/d3Hiz6Em6PCTOtJoA7lKtU/P2vmHXpZt2vDF+5RmxcB0pbbie9xPXRTg0u 1Gk1nmQWagi3XiOOvaSS86XGlMnMcIU= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf07.hostedemail.com: domain of yangyicong@huawei.com designates 45.249.212.187 as permitted sender) smtp.mailfrom=yangyicong@huawei.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1661156615; 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: references; bh=H5nsUMra4gtUveElEktCp5rG0ynWw4ECmRbGS/cFQvY=; b=vK6+rjvz36jZF41ufrUJiROaYSiZqlzKKef4BgNIm9/+6s39Y7T1rYtASRf56YTYkj/W5G zBzsSyFxEZmgzc/qjgF/gN7gdjBqd0wWelcrIHL+VSaScsX9L+VH0eVDLkIdT8MgbbZbDW F7kJMird248ZDdh8c3n4toTw3KhR2FI= X-Rspamd-Queue-Id: 4774340044 X-Stat-Signature: 9bwxfigg9j9axghzafefzshbtzxetcs5 Authentication-Results: imf07.hostedemail.com; dkim=none; dmarc=pass (policy=quarantine) header.from=huawei.com; spf=pass (imf07.hostedemail.com: domain of yangyicong@huawei.com designates 45.249.212.187 as permitted sender) smtp.mailfrom=yangyicong@huawei.com X-Rspam-User: X-Rspamd-Server: rspam09 X-HE-Tag: 1661156614-493005 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: From: Yicong Yang Though ARM64 has the hardware to do tlb shootdown, the hardware broadcasting is not free. A simplest micro benchmark shows even on snapdragon 888 with only 8 cores, the overhead for ptep_clear_flush is huge even for paging out one page mapped by only one process: 5.36% a.out [kernel.kallsyms] [k] ptep_clear_flush While pages are mapped by multiple processes or HW has more CPUs, the cost should become even higher due to the bad scalability of tlb shootdown. The same benchmark can result in 16.99% CPU consumption on ARM64 server with around 100 cores according to Yicong's test on patch 4/4. This patchset leverages the existing BATCHED_UNMAP_TLB_FLUSH by 1. only send tlbi instructions in the first stage - arch_tlbbatch_add_mm() 2. wait for the completion of tlbi by dsb while doing tlbbatch sync in arch_tlbbatch_flush() My testing on snapdragon shows the overhead of ptep_clear_flush is removed by the patchset. The micro benchmark becomes 5% faster even for one page mapped by single process on snapdragon 888. -v3: 1. Declare arch's tlbbatch defer support by arch_tlbbatch_should_defer() instead of ARCH_HAS_MM_CPUMASK, per Barry and Kefeng 2. Add Tested-by from Xin Hao Link: https://lore.kernel.org/linux-mm/20220711034615.482895-1-21cnbao@gmail.com/ -v2: 1. Collected Yicong's test result on kunpeng920 ARM64 server; 2. Removed the redundant vma parameter in arch_tlbbatch_add_mm() according to the comments of Peter Zijlstra and Dave Hansen 3. Added ARCH_HAS_MM_CPUMASK rather than checking if mm_cpumask is empty according to the comments of Nadav Amit Thanks, Peter, Dave and Nadav for your testing or reviewing , and comments. -v1: https://lore.kernel.org/lkml/20220707125242.425242-1-21cnbao@gmail.com/ Anshuman Khandual (1): mm/tlbbatch: Introduce arch_tlbbatch_should_defer() Barry Song (3): Revert "Documentation/features: mark BATCHED_UNMAP_TLB_FLUSH doesn't apply to ARM64" mm: rmap: Extend tlbbatch APIs to fit new platforms arm64: support batched/deferred tlb shootdown during page reclamation Documentation/features/arch-support.txt | 1 - .../features/vm/TLB/arch-support.txt | 2 +- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/tlbbatch.h | 12 ++++++++ arch/arm64/include/asm/tlbflush.h | 28 +++++++++++++++++-- arch/x86/include/asm/tlbflush.h | 15 +++++++++- mm/rmap.c | 19 +++++-------- 7 files changed, 61 insertions(+), 17 deletions(-) create mode 100644 arch/arm64/include/asm/tlbbatch.h