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 92885C77B61 for ; Mon, 24 Apr 2023 10:22:49 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DCD496B0071; Mon, 24 Apr 2023 06:22:48 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D7D0C6B0074; Mon, 24 Apr 2023 06:22:48 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C1E7C6B0075; Mon, 24 Apr 2023 06:22:48 -0400 (EDT) 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 AFE166B0071 for ; Mon, 24 Apr 2023 06:22:48 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 7DA13A01FE for ; Mon, 24 Apr 2023 10:22:48 +0000 (UTC) X-FDA: 80715896016.06.0FEE0B5 Received: from mail-wr1-f45.google.com (mail-wr1-f45.google.com [209.85.221.45]) by imf11.hostedemail.com (Postfix) with ESMTP id 9C80040007 for ; Mon, 24 Apr 2023 10:22:46 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=gmail.com header.s=20221208 header.b=kvpQNBX9; spf=pass (imf11.hostedemail.com: domain of lstoakes@gmail.com designates 209.85.221.45 as permitted sender) smtp.mailfrom=lstoakes@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1682331766; 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=IEfL3vm8jgm1VnHtQznTCIo9BSXh+ZMvNh1ToPMDn6I=; b=aYtNUHKNVW+eLvSwx0w3tzECjY8TrXGZf4Qhg0wV75UF/L/o6omgbTFTcLSU5hC75zbf9E Lx8O0dQpueh7NgdY9DMso+Q2qkEfIoGzxxjF5po1Iz/29Uh0liK5xzUp3ll9+CE3Z8by7E Pl+HFOF39oEhUddmsBv89xwbWlqwDLg= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=gmail.com header.s=20221208 header.b=kvpQNBX9; spf=pass (imf11.hostedemail.com: domain of lstoakes@gmail.com designates 209.85.221.45 as permitted sender) smtp.mailfrom=lstoakes@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1682331766; a=rsa-sha256; cv=none; b=yyV+KeY0kLJViIC55NuEN+EtMKZU2NaczSKRK6Xl97EJU577mK3jGoJbC+E1QSFGbBpVEH veziymye9JhUh1N6toZIdCLluBfEWZigIqYgZa9Oa/oJHCoVmG9XA0lJpq0JDiOKDzR7YN Im5i138eOFq2y2XFPf2TflzLkyXWmOs= Received: by mail-wr1-f45.google.com with SMTP id ffacd0b85a97d-2fde2879eabso3888129f8f.1 for ; Mon, 24 Apr 2023 03:22:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1682331765; x=1684923765; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=IEfL3vm8jgm1VnHtQznTCIo9BSXh+ZMvNh1ToPMDn6I=; b=kvpQNBX9elSm2h7ZkPLX1IVqVONIEiA8n7Aj06sI5R/eqZWebx79uvkJQq9JF+sdhv ROTLP8eMi1cq8hu0+cTcKsfcUeB9ndq6TBurOiQ6MKE8Xoo/KDaJrwh6RacKYCjskq6k 8DiY2Zq/etRkxkG4KA++6LgR6ui1A0aau5LYEm66y4flmWg+a54iLW1DlK37O8PTj8Kq /BMgaWw2Icnbtu1+W/0fSyM4rMtmwR+zWVjO79IRcwc4te+tci52v7pjCnUVgLGXru6q gU1VqmOpiOnbI6b7DRnWgYSdXf/s2CElRlS02TdNoPyRjTwDogQI7gc77eWX847nx/7m sZAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682331765; x=1684923765; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=IEfL3vm8jgm1VnHtQznTCIo9BSXh+ZMvNh1ToPMDn6I=; b=lY7dCRVMruDL/OX44vo1kSInTCbM2OGDLy1isiSL/K+HVH0gVy81gFVwww5gYv5Q0o 2j/yD941YJ7Q29fRSumXZSoDc5kjFJ05WQP2StcfPrO/KaDZKtoJSutJ5brlb+jCMm/n L6OlBM3vO8PQ2juhLGdZ9eOtVf7/ZkjOlHmNIJ7NR5HN+VBkjk1Cc3oeU9DIrmqJdbo/ t3Dq9sP0lzmujA/YqQbTfcODw3zdy5BbIBhFXhMvk2dRae5lAUQS5Hojp8MUZQPPjdC/ k/gTId1wAPJ5uYezzw5d70Q3Sq/DPzmaHTnqivt5aCqoJmOPH+6gsbmbyRqHpCBzbCAH 4nkg== X-Gm-Message-State: AAQBX9fKdSZRgtT6C4flwbfqpi2nMO2tduFsbY0FR/Z1r/YwJBKTgFLZ wLtDQ+oCdPRp3zB/rfSjw+w= X-Google-Smtp-Source: AKy350aYyyIW4zw7l0KCAdCx2sQqU0kn+WrS8yImuvFNaUgVtru1m/uboKcoR4LgsiDvI6Tm6b6B1Q== X-Received: by 2002:a5d:526e:0:b0:2f7:8f62:1a45 with SMTP id l14-20020a5d526e000000b002f78f621a45mr9556108wrc.66.1682331764943; Mon, 24 Apr 2023 03:22:44 -0700 (PDT) Received: from localhost (host86-156-84-164.range86-156.btcentralplus.com. [86.156.84.164]) by smtp.gmail.com with ESMTPSA id r3-20020adfda43000000b003047ae72b14sm2060393wrl.82.2023.04.24.03.22.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Apr 2023 03:22:44 -0700 (PDT) Date: Mon, 24 Apr 2023 11:22:43 +0100 From: Lorenzo Stoakes To: Uladzislau Rezki Cc: Michal Hocko , lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, Baoquan He Subject: Re: [Lsf-pc] LSFMMBPF proposal [MM]: Eliminate vmap/vmalloc lock contention Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam03 X-Stat-Signature: dim94jrmu738za1qwryxwfitqtsywnne X-Rspamd-Queue-Id: 9C80040007 X-HE-Tag: 1682331766-712031 X-HE-Meta: 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 fu3HivnX pcIc0/nd5JgCnUri4uYXZqHivOFgnhMDTCKJz8BViDBKsQ9+2idd/nMm6+y5gUlDpskhHkqPzM6pCJRiYvAcq21wE6xD6P9UnWJIaIF9XR5S7+4ZlrW+zYJjiSPZ8ZRTbH1DIqOsG/8GXL9dAEn7H92iXJy6SlA1jy1VANBPaaFdVo28JzYJsOHTRFmizmjT7nI6mtRXetn1cnM/h2lvjU3L+sfCLFmzWFiMjUAkxTTZinvchxUUZtY3V/v1z/xe0FYlnEZSCR9gS/qpyEsVZiM5ucYdZn8Ktv4f35tn+mzNASjIm6I2AvjgrE9pUEBf32tKMRMwvBugXfwI2inlEQ+SYN+bcnUJD4bIP5HzzuZAmFz3lMCMk8mxfx3lnhlwDnDXcbSXzMmlFwuqQOrtmv68QvBv6UsJDu/D4CqKkXhtSarrBNGSrV3xHRP+GunZG6liI 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 Mon, Apr 24, 2023 at 12:08:22PM +0200, Uladzislau Rezki wrote: > On Mon, Apr 24, 2023 at 10:55:20AM +0200, Michal Hocko wrote: > > On Mon 24-04-23 09:44:00, Uladzislau Rezki wrote: > > > On Fri, Apr 21, 2023 at 02:03:43PM +0200, Michal Hocko wrote: > > > > On Tue 28-02-23 17:42:43, Uladzislau Rezki wrote: > > > > > Hello, LSF. > > > > > > > > > > Title: Introduce a per-cpu-vmap-cache to eliminate a vmap lock contention > > > > > > > > > > Description: > > > > > Currently the vmap code is not scaled to number of CPU cores in a system > > > > > because a global vmap space is protected by a single spinlock. Such approach > > > > > has a clear bottleneck if many CPUs simultaneously access to one resource. > > > > > > > > > > In this talk i would like to describe a drawback, show some data related > > > > > to contentions and places where those occur in a code. Apart of that i > > > > > would like to share ideas how to eliminate it providing a few approaches > > > > > and compare them. > > > > > > > > It's been some time since you brough this up. Has there been any > > > > progress on the topic? Do you still find it important to discuss it at > > > > LSFMM? > > > > > > > The idea about sequence was/is: > > > > > > 1) Give an overview on the proposal; > > > 2) Submit patches to address the problem; > > > 3) Start a discussion over lkml with people who are interested in it; > > > 4) Send out a complete solution. > > > > Thanks for the clarification. The usual LSFMM format is strongly > > discussion focused. Long presentations are usually discouraged and they > > should only introduce people to the underlying problem to kick of a > > discussion. > > > I have not posted yet any RFC and have not kicked it yet. Though people > are aware the problem. > > > > > That being said, IMO it would be helpful to have some material on the > > mailing list before any discussion could be productive. > > > This is what i have so far: > > wget ftp://vps418301.ovh.net/incoming/Fix_a_vmalloc_lock_contention_in_SMP_env.pdf > > I can, of course, move it forward over lkml only. If you are fully > booked or there other reason then please just withdraw my proposal > from your conference. For what it's worth I'm definitely interested in attending this session if it goes ahead. I am sure Baoquan, if he's attending LSF/MM, would be too! (cc'd).