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 7AF46E77180 for ; Mon, 9 Dec 2024 14:43:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EAB2F8D0070; Mon, 9 Dec 2024 09:43:01 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E31998D0058; Mon, 9 Dec 2024 09:43:01 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CD1E58D0070; Mon, 9 Dec 2024 09:43:01 -0500 (EST) 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 AECCC8D0058 for ; Mon, 9 Dec 2024 09:43:01 -0500 (EST) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 3DEF11C700E for ; Mon, 9 Dec 2024 14:43:01 +0000 (UTC) X-FDA: 82875686880.27.E2E8114 Received: from mail-wr1-f51.google.com (mail-wr1-f51.google.com [209.85.221.51]) by imf25.hostedemail.com (Postfix) with ESMTP id 331A9A0009 for ; Mon, 9 Dec 2024 14:42:43 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=suse.com header.s=google header.b=QPiOQBru; spf=pass (imf25.hostedemail.com: domain of ptesarik@suse.com designates 209.85.221.51 as permitted sender) smtp.mailfrom=ptesarik@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1733755363; 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=nkwsX/4Xva/aw3/I8I2kwIJd9M/PGmCc4Ypj6qQ29AM=; b=SHyp0yoOLII7daRq2DBM9KltdS9TXDaT1vRPONBvbnuiMemVIFbH4tF54v9TwgOqsBNYSS YIx16YUJxiWmoqevje0ieXoPTBZeane0r4xKGzY7esnhqaBRD6g8zl2WYbF1azgCNAgaWc T2eeKSCBttMm/RIVNMDqvpoyzidVpuo= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=suse.com header.s=google header.b=QPiOQBru; spf=pass (imf25.hostedemail.com: domain of ptesarik@suse.com designates 209.85.221.51 as permitted sender) smtp.mailfrom=ptesarik@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1733755363; a=rsa-sha256; cv=none; b=Kf0K4CuDt3wj0YfKuUOq+4zsIg05e0tAt3KhbYEAO+rknHRpj9TI1ffADJP9cHkBq4+YzZ onHgFEGDurW5xG9jKTaWMKLeSxbwNN5sEfh+kVi83cS6MhLxd1RMeMqtG8KrNVvhWhOp9k 3Na2NGjwQNDvJv0zy0gpSB0pZOOlw2k= Received: by mail-wr1-f51.google.com with SMTP id ffacd0b85a97d-3862c78536bso341559f8f.2 for ; Mon, 09 Dec 2024 06:42:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1733755377; x=1734360177; darn=kvack.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=nkwsX/4Xva/aw3/I8I2kwIJd9M/PGmCc4Ypj6qQ29AM=; b=QPiOQBruGuj+UnQgmeVEuLB0vIU+XwFlrXqqn601y+kRM/E83DQuv+mLiJHRYGjzU7 IbtfaW8v6me+UF6XwuPFT6EgtX4HS3U0PSYd8WPqTvkRNXvBLlqScmWwCT1JTpQG7ZAY VG+j3CukHIuqFZm3K1+bM5nN4lg74rimaKSVzAG3SLpS7++ozFvLrtXGz3R0CMMyVmf2 VUEESfZb13JsiPNo2ALVpmzOW5b5WS9niFQZO2P2XdDpi9RnUFWTBCR6yv0XasX5MSQt Ne/aLwBGa2DEC11fEoPOTortU6rWCQoPnrZurkA9vY5xfrCisVYSD0zMAm+vjcodAMGI nBJw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1733755377; x=1734360177; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=nkwsX/4Xva/aw3/I8I2kwIJd9M/PGmCc4Ypj6qQ29AM=; b=YrHlj0Ki8qGYFfEQEazDTS4qEw+OuTTm09wrjUiU7/NVm+ZT8NPfFyct0IVBg7W32g k9Gyhm/rZkeudpm1eWQZc4F5f2gKRB9/+IOZM3hWq/TxNrIZGmNoejGUh0pxMeoM5i81 NqroF+M+7f1kzBRd94HUy5jVApsTJpV+TTXidptexHu72WX1M/mctLMSdXBgu8Pojp5D OCzdr2mKEZDSBetGkw+T4HwUuJhTkRp8WBNOxijSF+oQzdypt667GKu9t4gqlVZ6rfmM ovstvImBENwrHI5d4IC8+OrflMBkN8A5LdoerYXYcNMFpqb+T0uaBabVOmA+xl8KpTW9 Z7QQ== X-Forwarded-Encrypted: i=1; AJvYcCU6h4ryu6LpxVAG9oNlTdGgCaG+kJcEDnQYfFx6zBhHCnUlHAMRZTpzwqm1beMcP8cbY0sezxX+1Q==@kvack.org X-Gm-Message-State: AOJu0YwV4EnKEOcHB3Y3vVAtPnmOOlhlGKgWbrccdxZu35TUXKG3opyD uqgj5LTPY2bifWaHG6FVtjmeFN68T+cdPyQe2mK1waIAAEgcGe3idE3X56egDLU= X-Gm-Gg: ASbGnctzG6u3O7OW7UA7UU2B6l+SQTQN+03fw7lLDu1ho82OFul8o7XNw7bhCHuUWVa jHrZan1GhlXnH2Fy6GYbLHWPSigWsFv8NU4vcisVwVPJSIwj+uaNZ0MHbow9KfALhtpEheSxOit 6XLaPkd0XnksEKILAR4qFHguDVAlC4V5/kH3cCZCizwhEj1hwtBVhnThxRnE78RU3fcnkqoq0OO mJ0b8gHrb6w2a+Geurqp83w4QE0WhjGo6xjq7b4ZA8EH3sY2oXJDBcfSPdAIIaWo3GLHufUcCZo PXeVMa3kxjLHhJhw2B58hJJZ02ABZhdbVUSRycWvH3REjUPVJJC1odQ= X-Google-Smtp-Source: AGHT+IFS9ZOU0lVFyWUQ84y6baV41ONm7JGT6TkRTJEtzq0JeBL9l/n9rsr90siOB4OTv3dodfZukg== X-Received: by 2002:a05:6000:1846:b0:385:fd31:ca24 with SMTP id ffacd0b85a97d-3862b3cea6dmr3365934f8f.12.1733755377482; Mon, 09 Dec 2024 06:42:57 -0800 (PST) Received: from mordecai.tesarici.cz (dynamic-2a00-1028-83b8-1e7a-3010-3bd6-8521-caf1.ipv6.o2.cz. [2a00:1028:83b8:1e7a:3010:3bd6:8521:caf1]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-38636e05568sm7300809f8f.39.2024.12.09.06.42.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Dec 2024 06:42:57 -0800 (PST) Date: Mon, 9 Dec 2024 15:42:52 +0100 From: Petr Tesarik To: Peter Zijlstra Cc: Valentin Schneider , Dave Hansen , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, bpf@vger.kernel.org, x86@kernel.org, rcu@vger.kernel.org, linux-kselftest@vger.kernel.org, Steven Rostedt , Masami Hiramatsu , Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Paolo Bonzini , Wanpeng Li , Vitaly Kuznetsov , Andy Lutomirski , Frederic Weisbecker , "Paul E. McKenney" , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Andrew Morton , Uladzislau Rezki , Christoph Hellwig , Lorenzo Stoakes , Josh Poimboeuf , Jason Baron , Kees Cook , Sami Tolvanen , Ard Biesheuvel , Nicholas Piggin , Juerg Haefliger , Nicolas Saenz Julienne , "Kirill A. Shutemov" , Nadav Amit , Dan Carpenter , Chuang Wang , Yang Jihong , Petr Mladek , "Jason A. Donenfeld" , Song Liu , Julian Pidancet , Tom Lendacky , Dionna Glaze , Thomas =?UTF-8?B?V2Vpw59zY2h1aA==?= , Juri Lelli , Marcelo Tosatti , Yair Podemsky , Daniel Wagner Subject: Re: [RFC PATCH v3 13/15] context_tracking,x86: Add infrastructure to defer kernel TLBI Message-ID: <20241209154252.4f8fa5a8@mordecai.tesarici.cz> In-Reply-To: <20241209121249.GN35539@noisy.programming.kicks-ass.net> References: <20241119153502.41361-1-vschneid@redhat.com> <20241119153502.41361-14-vschneid@redhat.com> <20241120152216.GM19989@noisy.programming.kicks-ass.net> <20241120153221.GM38972@noisy.programming.kicks-ass.net> <20241121111221.GE24774@noisy.programming.kicks-ass.net> <4b562cd0-7500-4b3a-8f5c-e6acfea2896e@intel.com> <20241121153016.GL39245@noisy.programming.kicks-ass.net> <20241205183111.12dc16b3@mordecai.tesarici.cz> <20241209121249.GN35539@noisy.programming.kicks-ass.net> X-Mailer: Claws Mail 4.3.0 (GTK 3.24.43; x86_64-suse-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 331A9A0009 X-Rspamd-Server: rspam12 X-Stat-Signature: utrik51n34sz3rkbp6qjy4b3tdeozi5p X-Rspam-User: X-HE-Tag: 1733755363-864589 X-HE-Meta: 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 QlDSPQLQ jCcPzPxX8auErvtYQuC9DdGQCYXGWYZj/mQH5YMbGzt1WjvQgpYz7+wFsKqokjxeMZuHXFwo1OxN/CgIZTwtKpxDlt2RFDjzW2niSVD6cDS6D4OpGmQXYc6jXSagQKfDg5fzPVuHJdzJs9ADWn/YqifpUZ02Na838Lpfx9vRLdmNQRadlhQl+f+byIiiYSjL3wzk/N5qDs8MWnqdLr4hzDbg3sEzqKt96strcIze2NiELpcGawzEhGsPVBFONxG2Q3JnC26MUKSZZxpW6H6mJD8sjwDkWDCwyz52QUTzoDv/Tei1WvsCylUOHHQHEa2PqpdRstqijIIgZL5SAQzuBWsMtyvUHpnekfpd/od/NXtCXTTAK7mPIKgqGqDnteCbJ5mC5WN7RSz1PeT8= 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 Mon, 9 Dec 2024 13:12:49 +0100 Peter Zijlstra wrote: > On Mon, Dec 09, 2024 at 01:04:43PM +0100, Valentin Schneider wrote: > > > > But I wonder what exactly was the original scenario encountered by > > > Valentin. I mean, if TLB entry invalidations were necessary to sync > > > changes to kernel text after flipping a static branch, then it might be > > > less overhead to make a list of affected pages and call INVLPG on them. > > No; TLB is not involved with text patching (on x86). > > > > Valentin, do you happen to know? > > > > So from my experimentation (hackbench + kernel compilation on housekeeping > > CPUs, dummy while(1) userspace loop on isolated CPUs), the TLB flushes only > > occurred from vunmap() - mainly from all the hackbench threads coming and > > going. > > Right, we have virtually mapped stacks. Wait... Are you talking about the kernel stac? But that's only 4 pages (or 8 pages with KASAN), so that should be easily handled with INVLPG. No CR4 dances are needed for that. What am I missing? Petr T