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 5D619ECAAD3 for ; Thu, 15 Sep 2022 08:50:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 571EB8D0001; Thu, 15 Sep 2022 04:50:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 520F76B0073; Thu, 15 Sep 2022 04:50:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3E87B8D0001; Thu, 15 Sep 2022 04:50:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 2E75C6B0071 for ; Thu, 15 Sep 2022 04:50:31 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id D6C9580D23 for ; Thu, 15 Sep 2022 08:50:30 +0000 (UTC) X-FDA: 79913698620.04.E8C0904 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf02.hostedemail.com (Postfix) with ESMTP id 372D9800AF for ; Thu, 15 Sep 2022 08:50:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=KSEO7grr1p/8DaZzm61xRKuesIZdIt0bL/jRmRVRgkc=; b=eWfNCTgy4m5xfBnkmORobqoHKt sFJ6c69laoIcGWhFYCSHxNjZUb+0eC7j6x+mmTaJFyE+MKvFrR7QsQEVXAW4KyPQgXe+XXEQimLhU Y5Zwbogw7k9JbmeB/1mojdNG2sHLQ2wcu3JvJFCBfxhHMrKekY8CN9BIUmBd6PEvj5+bm0/2ocnBV Qenn+6RcPTKt0pLFW/RfTGbYLhecpztpv7IbWLR12+Dq7OfZaMdC7+Bh1oVwO7I+WN+958sg0EBJA rP/r//3zdykpw7yKoMve0utqkXgMBahbgyWfLj6vf3eyhOivM6bweBMIAmKNn0kCz1eKGlCsYTXrf awa3nFTA==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94.2 #2 (Red Hat Linux)) id 1oYkZb-000wGY-Qo; Thu, 15 Sep 2022 08:50:15 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 69FC530029C; Thu, 15 Sep 2022 10:50:12 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 4EB85201ABB97; Thu, 15 Sep 2022 10:50:12 +0200 (CEST) Date: Thu, 15 Sep 2022 10:50:12 +0200 From: Peter Zijlstra To: Joe Damato Cc: Dave Hansen , x86@kernel.org, linux-mm@kvack.org, Dave Hansen , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Daniel Bristot de Oliveira , Valentin Schneider , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [RFC 1/1] mm: Add per-task struct tlb counters Message-ID: References: <1663120270-2673-1-git-send-email-jdamato@fastly.com> <1663120270-2673-2-git-send-email-jdamato@fastly.com> <20220914141507.GA4422@fastly.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220914141507.GA4422@fastly.com> ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=eWfNCTgy; spf=none (imf02.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=peterz@infradead.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1663231830; a=rsa-sha256; cv=none; b=KYS52Ynw3e0Q6v6wPoHkloj/fc0IiVDRvpD20z1hQu5hsxc9uHo+mNZQv8TniNK223rTgR kwGViuaJ0588oGOfCERrMsfiWJGgryoZqRMLc/dC7SD7ZOs2s2knjv5ODh5Ad5Uftm92Ci BfZ/um8Z/j2zkYnRXJITFal/2Tfa9po= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1663231830; 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=KSEO7grr1p/8DaZzm61xRKuesIZdIt0bL/jRmRVRgkc=; b=op/2Vf5/aCWpfy/E65qrL6/xYOr0ikgBRf+tKJOtnqQETi16O4YnYnfEJo7ThnDqKDe0sV uyyduNbUx5DlKrNwFeSRUD/jcAH8oreqFZXFXiWWstZQKgUN4U9p6sJIGM6zUHEfc8t/5M 78Tasl9mi83p8KLe9b9R68cEC0t/RVM= X-Stat-Signature: i3uuubf1zbfb7z868ppq4mcpr9h7b4yh X-Rspamd-Queue-Id: 372D9800AF X-Rspam-User: Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=eWfNCTgy; spf=none (imf02.hostedemail.com: domain of peterz@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=peterz@infradead.org; dmarc=none X-Rspamd-Server: rspam12 X-HE-Tag: 1663231830-108552 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 Wed, Sep 14, 2022 at 07:15:08AM -0700, Joe Damato wrote: > I could patch count_vm_tlb... to account on a per-task basis. That seems > reasonable to me... assuming you and others are convinced that it's a > better approach than tracepoints ;) Well, we *could* do a lot of things, but we can all spend out cycles only once. Doing endless variations of statistics contributes to death-by-a-thoudsand-cuts. If you really think you need this, write yourself an eBPF program and attach it to these tracepoints. Then you get less cycles for useful work, but the rest of us isn't bothered by that.