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 0074DE64A87 for ; Tue, 3 Dec 2024 12:39:35 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4FB516B007B; Tue, 3 Dec 2024 07:39:35 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4AADF6B0083; Tue, 3 Dec 2024 07:39:35 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 372626B0085; Tue, 3 Dec 2024 07:39:35 -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 1B8626B007B for ; Tue, 3 Dec 2024 07:39:35 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 9FD7A41046 for ; Tue, 3 Dec 2024 12:39:34 +0000 (UTC) X-FDA: 82853603280.19.7F596FB Received: from mail-lf1-f43.google.com (mail-lf1-f43.google.com [209.85.167.43]) by imf19.hostedemail.com (Postfix) with ESMTP id 2EA9F1A000E for ; Tue, 3 Dec 2024 12:39:17 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=dxljikSl; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf19.hostedemail.com: domain of urezki@gmail.com designates 209.85.167.43 as permitted sender) smtp.mailfrom=urezki@gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1733229560; a=rsa-sha256; cv=none; b=IV92Fsh73Mu1h0yY7JuuaTvHIs2j+Cb2Sje41MTG9gmpibOFnVmljL7icOD+ryw69KZlxv A3/DijGON+2RREcB5F0spg7yybRKkrft1mWA50BOKH8p4N6T2q1fqC1H9T7BiGo6WHXTbF lg9oF9M78bIUWln6PNVEsA1/uBNAm1k= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=dxljikSl; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf19.hostedemail.com: domain of urezki@gmail.com designates 209.85.167.43 as permitted sender) smtp.mailfrom=urezki@gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1733229560; 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=vFxhjwEQHKpTIm6rgKkVijYZ+fIksPXhashUraPYMs4=; b=FhuxJYIMo+L3ah2K5qh8bayKtZNsnAA9lDpK6R3DJ5nu4dOofpFRLYjFuUZy2jWBog4FtV kifmkmQZ+37DtGFBJN3HQyw2QsUwdtjSaautjjEPf1QG+hqDgZYA62GzQbhkg/TkB1oX5X OHiTJtYfy6KY3zbOuW2VJdsW+p1cf0w= Received: by mail-lf1-f43.google.com with SMTP id 2adb3069b0e04-53df7f6a133so5761343e87.3 for ; Tue, 03 Dec 2024 04:39:32 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1733229571; x=1733834371; darn=kvack.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:from:to:cc:subject:date:message-id:reply-to; bh=vFxhjwEQHKpTIm6rgKkVijYZ+fIksPXhashUraPYMs4=; b=dxljikSlcm/tJs3W5UENFCYR8xajpLNuiiCWWro3m2homuW3MaKTAm1umxSSpPLoL0 ya89rlwrpBxJaxIyW74WZuD9Q/OHpe8Bnkqdz7wuJ7/9UkKNlpQCM3KvbFsIzrart/Fd 1E2V06E70EycqvrT+1ARprdA8xg+6qnBUPglp/exc3qTStVZWx/KmngNgik0thFOjJOm XUFJdW63Uws7n7CcN30bY6BT/HmOihF9fXEzHj1SZSEHSHfidPVgm1lPVOY6u49TfU09 noK5NbAnrSrzwfr8mY4EaLqQq/UU9XrDayGlEf5pV5wxQGBtFu5wiVUGeXZiIyW78iQD Yoiw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733229571; x=1733834371; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:date:from:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=vFxhjwEQHKpTIm6rgKkVijYZ+fIksPXhashUraPYMs4=; b=h5AjZmiwCcp9KbYnvQ74K7+Ow1Zk/FGC66f90phNHor82qRzPVOO1zTMc9J6PkA+oz 6HHiV5po/MH3Ov37j/FI22GRD/C5ee9YDEfyB7ukPLrO6ap4CaUBLamcbpgxxC3uW/Vj w3FPv80xXy7nwW2vPWOzFCWbrGUyHWqMwFKkgvTc5AyjErkI49ouwSYZj0Lx6RxiUWOB 0YfmwefwD1l1zPAiSoy+j5OEbGvCV3EjweJFwp9nk9Bs7AMCAA6ttuX2zkqiv62/jDRr jbgPLAmRESit4QCr1sdQdXc5rCZW3xsD4q5lA/x6n22yTJ4FYua9GyO7ay6H1i1Mkwqu jVuw== X-Forwarded-Encrypted: i=1; AJvYcCXmoGGM8aPqmpuyuHu7PO+Ui1IbEZu6J0EZR54ikK/CCoOelrSHpqnqCrwtiHow+4A7z9pgIvO6Rw==@kvack.org X-Gm-Message-State: AOJu0YwQG7UY7drT14TNbir29iZYQxyWUeT3QMXyc04V4aRz68HogWXX j8faDNzN/FwBjar+6OlHtr/alTSldF4j7d40BWS8H5FTlN8QHTIE X-Gm-Gg: ASbGncutZb7ibO0e/WxPYtUQYzxh1Jhx/joZoO/BTDesmI671HSTOEh4QZgzhh57/2e 0u7CQKqlzyJDj19taN8xqokrEVSzblHEnVa1vov8GLZvBQPHBP+TO1+UIhVDtDQ4exte+U5n5LT Wp5Dw+YVyRO54/FiR45MlyHpMYUMjPw/MwQuaW83L2L12Ximd9CkA08WDwf+icgAgyg8BkvbZ7r t0zKlPht0s6y0l3jBnC0N0sQ09fO+sVCyb2Rjmq6ZxhMascxvMPj16wTYkqSwUNEeR6bwodbqU= X-Google-Smtp-Source: AGHT+IG4MHL45fco/5PoB5PtaDieZUaMWK7lUgxPDf8A/Dg54zXVJYTct2xEw4EFK53rcuwMXwKhKw== X-Received: by 2002:a05:6512:b12:b0:536:56d8:24b4 with SMTP id 2adb3069b0e04-53e129ed0efmr1319398e87.5.1733229570525; Tue, 03 Dec 2024 04:39:30 -0800 (PST) Received: from pc636 (host-95-203-13-87.mobileonline.telia.com. [95.203.13.87]) by smtp.gmail.com with ESMTPSA id 2adb3069b0e04-53e1ac98755sm65921e87.74.2024.12.03.04.39.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 Dec 2024 04:39:29 -0800 (PST) From: Uladzislau Rezki X-Google-Original-From: Uladzislau Rezki Date: Tue, 3 Dec 2024 13:39:27 +0100 To: zuoze Cc: Matthew Wilcox , gustavoars@kernel.org, akpm@linux-foundation.org, linux-hardening@vger.kernel.org, linux-mm@kvack.org, keescook@chromium.org, urezki@gmail.com, wangkefeng.wang@huawei.com Subject: Re: [PATCH -next] mm: usercopy: add a debugfs interface to bypass the vmalloc check. Message-ID: References: <20241203023159.219355-1-zuoze1@huawei.com> <57f9eca2-effc-3a9f-932b-fd37ae6d0f87@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <57f9eca2-effc-3a9f-932b-fd37ae6d0f87@huawei.com> X-Stat-Signature: i5yydzxfjnfipd91wugpzcxr957emfty X-Rspam-User: X-Rspamd-Queue-Id: 2EA9F1A000E X-Rspamd-Server: rspam08 X-HE-Tag: 1733229557-184681 X-HE-Meta: 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 rmUQ4vfq yZywj9AhfUxYSLkA4cjky21tPDDUqpn0wgrwBU/c/7Vb1JQ3XabgedU9yUjZjPjciEzuJY7ulKCDtoZ7I+KxqBEuK2ywvtrMwuF+5Pd4huz1sHpxtrbLEuzEZ3lnQTsmgaljb89auek+bufMy3ViFRlx9DO0ryZQDnr/ol3blWBy6VB4iY3jRZo/I02vvZCKLmYk/6LZDOtztKGp1Zxi65TB6Gb/WplLytMgXrln0yF6KFd1iA9Wi0BPdfPWaZLcrLxq6/ZIkHyUrAJnrGDdiVdfkIL9VnhFmZWIrLkhrJeJdJdagmKiJM/IG9lOmArQFIYXAcgmhZweC67u4NAvUKfyNpq33iIwV2urRl6JWg5igSNni8ixwQYOcn9iu2S/0WQW9/APR9Ri+obmORZz1nKGHBmxnpLMGfcAjyDzOSaCYE1DvArtECY5Z0wQlckE2Yy84RWLmVh9oHtgfcjeiW2br6TQT2lFm8u3/ X-Bogosity: Ham, tests=bogofilter, spamicity=0.002887, 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 Tue, Dec 03, 2024 at 07:23:44PM +0800, zuoze wrote: > We have implemented host-guest communication based on the TUN device > using XSK[1]. The hardware is a Kunpeng 920 machine (ARM architecture), > and the operating system is based on the 6.6 LTS version with kernel > version 6.6. The specific stack for hotspot collection is as follows: > > - 100.00% 0.00% vhost-12384 [unknown] [k] 0000000000000000 > - ret_from_fork > - 99.99% vhost_task_fn > - 99.98% 0xffffdc59f619876c > - 98.99% handle_rx_kick > - 98.94% handle_rx > - 94.92% tun_recvmsg > - 94.76% tun_do_read > - 94.62% tun_put_user_xdp_zc > - 63.53% __check_object_size > - 63.49% __check_object_size.part.0 > find_vmap_area > - 30.02% _copy_to_iter > __arch_copy_to_user > - 2.27% get_rx_bufs > - 2.12% vhost_get_vq_desc > 1.49% __arch_copy_from_user > - 0.89% peek_head_len > 0.54% xsk_tx_peek_desc > - 0.68% vhost_add_used_and_signal_n > - 0.53% eventfd_signal > eventfd_signal_mask > - 0.94% handle_tx_kick > - 0.94% handle_tx > - handle_tx_copy > - 0.59% vhost_tx_batch.constprop.0 > 0.52% tun_sendmsg > > It can be observed that most of the overhead is concentrated in the > find_vmap_area function. > I see. Yes, it is pretty contented, since you run the v6.6 kernel. There was a work that tends to improve it to mitigate a vmap lock contention. See it here: https://lwn.net/Articles/956590/ The work was taken in the v6.9 kernel: commit 38f6b9af04c4b79f81b3c2a0f76d1de94b78d7bc Author: Uladzislau Rezki (Sony) Date: Tue Jan 2 19:46:23 2024 +0100 mm: vmalloc: add va_alloc() helper Patch series "Mitigate a vmap lock contention", v3. 1. Motivation ... Could you please try the v6.9 kernel on your setup? How to solve it, probably, it can be back-ported to the v6.6 kernel. Thanks! -- Uladzislau Rezki