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 C0B87C4725D for ; Mon, 22 Jan 2024 14:14:26 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 438BE8D0006; Mon, 22 Jan 2024 09:14:26 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3E9A78D0001; Mon, 22 Jan 2024 09:14:26 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2897E8D0006; Mon, 22 Jan 2024 09:14:26 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 154898D0001 for ; Mon, 22 Jan 2024 09:14:26 -0500 (EST) Received: from smtpin17.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id DCF191C13AA for ; Mon, 22 Jan 2024 14:14:25 +0000 (UTC) X-FDA: 81707142090.17.3A9D8F5 Received: from mail-yb1-f173.google.com (mail-yb1-f173.google.com [209.85.219.173]) by imf12.hostedemail.com (Postfix) with ESMTP id 1026540028 for ; Mon, 22 Jan 2024 14:14:23 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=PGzPm0WQ; spf=pass (imf12.hostedemail.com: domain of ioworker0@gmail.com designates 209.85.219.173 as permitted sender) smtp.mailfrom=ioworker0@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=1705932864; 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=ErCyol5PZx6qXhJjCCnqoBN3KenhOYwcv+uuntVnlDk=; b=TuFv8QydmC3cnvPEX57nGlFIPdQBalPp1CmzVqeUsHyzVsov91MRCGs9UP6zthRJf97t8/ 8UNU1aNInOWLVjkD8FvyFhOhE9BesbEqPZEzVKjhQna9XhqSQMK7xg+GYGSeDm5Qwd/29U U/KpQjL1NOFrWopaPMtKqST/1Oel53c= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=PGzPm0WQ; spf=pass (imf12.hostedemail.com: domain of ioworker0@gmail.com designates 209.85.219.173 as permitted sender) smtp.mailfrom=ioworker0@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1705932864; a=rsa-sha256; cv=none; b=tGLUQ4MpRgd/k8jGabfwqboX+7VUaf9TwWUMKZZeGk2rknHkxB81asqjPr3riHgH5bIdGV 6jDPupi50oADNBE6y/HiBFKJc0H2p4MvO8y1VHnobkX33uxJnAmF6PtRE1PpttQse1LYtd WPaurUuj2NlaO2zvocC+NNPbd0nsXfU= Received: by mail-yb1-f173.google.com with SMTP id 3f1490d57ef6-dc2540a4c26so1882209276.2 for ; Mon, 22 Jan 2024 06:14:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1705932863; x=1706537663; darn=kvack.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=ErCyol5PZx6qXhJjCCnqoBN3KenhOYwcv+uuntVnlDk=; b=PGzPm0WQZPmjgLf4Sn4PTDpFE/VMB3tbCPVEOE60RDGAG/ISGv5Am++kEtnQsgP8TW XzKPXS8nV1r1/I1SSEaSjJpbz8H/aV7jmFn0YR1VefBxDMOwWc9/eoOIzq1g8qCxnJZu TjTGT/E3PpWW1qtJzReyZH0zPXeBaYOMGKB37ojupi/rMNixGo04/pvRGfSWSceWV+df UoN99e17RKRnXs7R7RpEICfdHUNRGsoUiMP4I7QWTgEFKJkApf87+7J9LX5KNhnANmpR BVCY78vfDvnXigUmXWmh4zQqL3Q1+TPMJBPPgFxntwaeXOi0fGeIduJ/Ps2DoSVRwp/n rhAw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705932863; x=1706537663; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=ErCyol5PZx6qXhJjCCnqoBN3KenhOYwcv+uuntVnlDk=; b=GFlXVKDC/c7DRyBhJpSw6YqNMbl5qd4XE2bl/a5DWmCO+h/zCSoAj9cP0roxM8uE84 dV73cCevKCyt9AdqkNLEjTRZd0XItoDPAjEEaVKva3sXeorHFN4RPGGwqF28IALNrVBy 34JrbcOPsJNqJfdUqSNtI26rId6InQ2skDioY8v7IDCNPYSs4SxgfD+R7KzEvMnMR0Bh +SbvWQUlBRnf7lC45vOKW9CVUHDyD08zSrwjxc4NfNj9GZS2CXOWEk6mIGhWSq0Ic4cy cIMMCHW1/TO/cjp8uj3c8Svw2K0a2wtbRxf3xdzDOveJXkvoFoXUeW5cvMjLm6ysu/Jr 8JOA== X-Gm-Message-State: AOJu0YyFuHfSRI3Bm7+Q9gsKzzXa1wDjVRIRzRQJu3iuFNz6dEGGBXd2 zxP4Ulv722blp66Y/pZwsO5YTWpXlW27bhZ7YwG1kH+3tfNLlSz1YsdVkBb0juY5lOc1EM9yetj iWdBbb6r+ccKWUle1uie7HFjCESc= X-Google-Smtp-Source: AGHT+IGFEL9Ia3FpKndYQJjL+ePudTsCv9XRFC+t8B4dyNPevXxhMtw6VxkEKiXPKxsP1QtRS07YNey0Dodabekc8KU= X-Received: by 2002:a25:a161:0:b0:dc2:5528:7494 with SMTP id z88-20020a25a161000000b00dc255287494mr1950832ybh.64.1705932862956; Mon, 22 Jan 2024 06:14:22 -0800 (PST) MIME-Version: 1.0 References: <20240118120347.61817-1-ioworker0@gmail.com> In-Reply-To: From: Lance Yang Date: Mon, 22 Jan 2024 22:14:11 +0800 Message-ID: Subject: Re: [PATCH v2 1/1] mm/madvise: add MADV_F_COLLAPSE_LIGHT to process_madvise() To: Michal Hocko Cc: akpm@linux-foundation.org, zokeefe@google.com, david@redhat.com, songmuchun@bytedance.com, shy828301@gmail.com, peterx@redhat.com, mknyszek@google.com, minchan@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 1026540028 X-Rspam-User: X-Stat-Signature: inpfpisszptb97zgagy6jeosoyc445tp X-Rspamd-Server: rspam01 X-HE-Tag: 1705932863-3553 X-HE-Meta: U2FsdGVkX1+mT64Yt54mWXGUxtOGghGqBmGz/iaPrGFnXNNrPr6LkxL8GvoVxw8K5Rfj2HZASmIycKLzUvFRzd2yL9/TOMdiP7iG104/wdOnizFy2vCr4Nf9wvYjF4vJrAmRP+x5bByDwECCfzRjeBI+5N3VfCZqA+CZe85j+8+SgkVDrVOW7I1hNOGUvQAE1BBk1SBUdtB3kIQsb0HN8fcu8uneGVVtuH8K4tFXTgSX2q6rHe/NAAqdO1aYDBR3NBG7fuLQuypqPaieRwam+oTYW4su06CBFErKAD+gnVspfki2CviZ5B9Mc2Je7W64uAXU/PiIvxQHFHfmjFFLib3YzIYIyZsv14+op5cPUU1Lcksp6y2IB4wYZG19aBDBNSLG2ddghXSg2JH3kcOMED0oe4VtMXUnyeyrAHMsWV1lWSjGfPdy3X0k1UjKfTBiYx4NJPhO7p9KBXlY3O4okccbZSBy+Y5h6bxmCamjjXr8WnCCksIwPAidldb2l7zvnGS3f/HbM8LDBpDWLxfA3mZ2pQ2Kjhh6nqMd/k77qi8cfGjNs9k8mi09Nad5EiYrKhUGLJiSDzoL6v0DuOwT0mLbuBf5w+4NH9hzTUNA5ssdzdCivuA+FdQafCkrNR6yXQBmrCJq6rGf3EAafO7XuqHAQGFlCQSlP31eIewEbkAfEO0zvlEm9e5cVLyGeI/R8/tvYLRHBNscTilSG+uJi2YBPyEzzpsr/2pmb82Qcka3pjCPuMnxSbrzpPvrFZrkYXL/ffjnCz9a7belgq+4newZYhxGPYcBaX7tDFFtbXhY75wbEp6y3GjAQS6Q93yIKmJvPrHZQG1DQtNiKvgsppxzm9osWJVJbKsxrtjp+dLgaZoa5TJp9C5VnyIqTUj+i2cnlDh/xfF9h2h3GFfxkOU0bt3IbkkORD8EKd01Y2eK+ZD7mB5thiLtC7mq51j25tMNxwB0AYaAfgyaLQL iTPcbH4t cvLhl+BLq8pLRkEP4/8mtv7ymrIwPRInTY+Ginmp+/YWNDx4sSfhTOFAW9bvmNDdJZJyxQFD7Z/GGi8Inx+7jRKHJ3TZnPLFGY/3Ex2kc/b8KZd/AQVTEtiqe+WmOKB+SHDwpYr7lOuHhsapGVPXaKAjzDx2po9U93Me7L/+NuGL6zSZ1N0ciak1SDN7o7Xz1JQhruy51d9O1dxtnwKGj0BzspyIUPCZdOZbKkZLf+ABU+E5s4mFFvZHbh92er1DkDJm+fnYmGRsCK9LH5zlBF9FaxRF3f9lRgHHMctxeROYzdp/2h1kP+hEo0pTfHtgLOJgn9aUzwTtLd6kF6ElbBZbtjq5Q0MnqhpIEIApsvOMjY4Xlzj1K91HIwLmHZI5eLda/+iJlcV81KZDZSv2bJoCv/6K5ko3R8v/W75jM7WIxULCYbtPBJxwymldMyreoYSm0wxYJtJ85SOs= X-Bogosity: Ham, tests=bogofilter, spamicity=0.002696, 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, Jan 22, 2024 at 9:50=E2=80=AFPM Michal Hocko wrot= e: > > On Sat 20-01-24 10:09:32, Lance Yang wrote: > [...] > > Hey Michal, > > > > Thanks for your suggestion! > > > > It seems that the implementation should try but not too hard aligns wel= l > > with my desired behavior. > > The problem I have with this semantic is that it is really hard to > define and then stick with. Our implementation might change over time > and what somebody considers good ATM might turn int "trying harder than > I wanted" later on. > > > Non-blocking in general is also a great idea. > > Perhaps in the future, we can add a MADV_F_COLLAPSE_NOBLOCK > > flag for scenarios where latency is extremely critical. > > Non blocking semantic is much easier to define and maintain. The actual > allocation/compaction implementation might change as well over time but > the userspace at least knows that the request will not block waiting for > any required resources. I appreciate your insights! It makes sense that a non-blocking semantic is easier to define and maintai= n, providing userspace with the certainty that requests won=E2=80=99t be block= ed. Thanks, Lance > > -- > Michal Hocko > SUSE Labs