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 BE395C0218D for ; Thu, 30 Jan 2025 02:15:29 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DD25B2800A8; Wed, 29 Jan 2025 21:15:28 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D5B0028009F; Wed, 29 Jan 2025 21:15:28 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BD50C2800A8; Wed, 29 Jan 2025 21:15:28 -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 A149E28009F for ; Wed, 29 Jan 2025 21:15:28 -0500 (EST) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 4D640120726 for ; Thu, 30 Jan 2025 02:15:28 +0000 (UTC) X-FDA: 83062501536.03.D846B01 Received: from mail-pl1-f177.google.com (mail-pl1-f177.google.com [209.85.214.177]) by imf24.hostedemail.com (Postfix) with ESMTP id 75270180009 for ; Thu, 30 Jan 2025 02:15:26 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=yc4f1QHd; spf=pass (imf24.hostedemail.com: domain of yuanchu@google.com designates 209.85.214.177 as permitted sender) smtp.mailfrom=yuanchu@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1738203326; 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=zL2bVoQzvTlTDBwGlrT2Hn0lIShKB5FFgTt+rq/GXUE=; b=oe/ozJHE99fzAvhghFv9Uh/ovb0yX1LiM6oIsLw0Zlgw/BL7pCSB239+ifUovenAhG/21j R7aNGevHPv376RHXqx5MUVX+cfBh0/4EGE4KizNfRav1/I0rYxVnk4S02jNRmRR8eHZ9ZI n44PC8x1ZglJZOdG8o+TK7uMv8ZYR0I= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=google.com header.s=20230601 header.b=yc4f1QHd; spf=pass (imf24.hostedemail.com: domain of yuanchu@google.com designates 209.85.214.177 as permitted sender) smtp.mailfrom=yuanchu@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1738203326; a=rsa-sha256; cv=none; b=VN+2Bn8PeQe1UGA9bajTBT5h3D2j1Jq3ICx2tEuJahcJ1Cs7cc2BYRiuAKxBhIDz0D01Dl PWjO//ZmY8ltkFwdNjZ4QExNAxZFqVBvWIK4NR9o6c0UxkyxG/0NSsThwsvZ4TZZVtlFi8 2Uv/O3zJRU89HX1RmTkOZ7rIUR9+HFQ= Received: by mail-pl1-f177.google.com with SMTP id d9443c01a7336-215740b7fb8so70725ad.0 for ; Wed, 29 Jan 2025 18:15:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1738203325; x=1738808125; 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=zL2bVoQzvTlTDBwGlrT2Hn0lIShKB5FFgTt+rq/GXUE=; b=yc4f1QHd8Q0GF4+GNJiiuGKJiqIjBCoV8ld8PftixjUuA3ooYWPWw2LXyg9H71xKN5 qz+B8Ez+ma25YSt1mNSoPCnHeEEQHs6mdLsssBy4notGA4nzojVsdYkSjBXCik0cAvVY xhjdK24nxkM5y9WHAOob7cyoRC092Ubgm6s3C5EdwZj1dEwZmhJWnlpjruAPTx2dJaD8 vNRcLYo1ooFsvgQYaoBvznUJgI24jIEzQmDGMBptMTnrxn7DhcmechVQ9k4ltOC8SHR/ wptoyMsNnkPZwejt2wXFXxNAb0ZD09HwACLCxsEl00k4VMIYjkq+YhwVWIN1lmoClXpM pRkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1738203325; x=1738808125; 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=zL2bVoQzvTlTDBwGlrT2Hn0lIShKB5FFgTt+rq/GXUE=; b=TIb1DwU+AipDH1vQRjXKZJkkHo+3SNlOQ6YEWuKEeYaFn81Uprk8sxNYr5XGbBx7pp NIhq0AoBgCoxo92gk7JDxcUSwzUX+tS6nvNSmMzGut4x5qgGAZaDsQCqDNFCw4ivqHTv noymZU28bte4xplDS7dgu+rZC2TNOgoNIJD8xypAGA3PZ3gXFUfN/YfMnuNcQpaXqgfQ 7dzgLndSCvkKO9Cb42EXs+pp7fLv/JWjXyTTQvKOAkJsaYWDYLFra45qlkPX/bOLmB+h qUj3Sv8bHm5bIIyv4RtQNWYX4uH2H/IFcsevQXH5lb/gXvOYqY34bQjvgvhEFTTHyDFY adhA== X-Forwarded-Encrypted: i=1; AJvYcCVNMujPkhLpZxBDHW4hLsa2Zj76z9T3OQMSX4EWmyARi/88YcbWdvWyAzCmy/s0cTMLNlQFhtZWRg==@kvack.org X-Gm-Message-State: AOJu0Yx8CA9Ft7TSl0Rn1mxmiT6y1V3NosSqNmhwo9W9YW01b0Mn3mgs CcViMU3cndJID+BNbDOBfTzlWMUXQzVZOSRZNFaZsNNiMDyG+viYUpOirWbAjBzzGiGS7lqmewy b3vJM6aTwKgOuCazRaGGjKTU0ys0lGbaWlukK X-Gm-Gg: ASbGncs+34n3J2jsjoCVSLouKGNN/LL25FJOswhK3l2t6WDHecjdSOCkNUcros3C3nK cPs9lMigvv2jTqlOYOsdqkHmKXLAYpWMJFH5R2Ni667H65lycgCzvWv12LNSInPYw9s2x+zOUfA BArTAOluqQpnf91h/hHRtRIvUNKg== X-Google-Smtp-Source: AGHT+IHiw/l5Uly3TxfT60Bv+QsNpJ//IE32/Ma11U6wfwDQu474zQr3xgWxbyPKTz1IoSdCOksR8RL+mMMOIfQlrUY= X-Received: by 2002:a17:902:6b01:b0:215:7ced:9d67 with SMTP id d9443c01a7336-21de2479655mr1342275ad.24.1738203324959; Wed, 29 Jan 2025 18:15:24 -0800 (PST) MIME-Version: 1.0 References: <20250101222039.74565-1-sj@kernel.org> In-Reply-To: From: Yuanchu Xie Date: Wed, 29 Jan 2025 18:15:08 -0800 X-Gm-Features: AWEUYZmwbhWtFQt8BXt48jdRBHbwVMypC1AoImNfsGOiL3MKq8A1xAi_a-yZ7Ek Message-ID: Subject: Re: [LSF/MM/BPF TOPIC] DAMON Requirements for Access-aware MM of Future To: Gregory Price Cc: SeongJae Park , lsf-pc@lists.linux-foundation.org, damon@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, Raghavendra K T , Jonathan Cameron , Kaiyang Zhao , Jiaming Yan , Honggyu Kim Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 75270180009 X-Stat-Signature: q4zfth5ypr8wnu9qpkbum4jo916d7pwx X-Rspam-User: X-HE-Tag: 1738203326-228504 X-HE-Meta: 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 waAHH05w ZhJGzK93WtsVxR+JQYMdoQehJKvrTfiMYcvPjyKuNhiBeINtQrxuH76zJKxyZ6Rmb2Nj8uNscLAfvCQw6PDXYU1YPZw0rEfuJEeCRynlqIOkZjWMs3nF7NY4bhPe5ri+4dGfbMLsHKjviz+bkyMLIJsYpGgklluHqB2zHcFC7hB8WtnNkq91tGbbPiPF8JCznwHn+G4QV9JxcTbyCMh/Jx9ukIQ3UGT3Rcx6j9n2nKIvyUSeDrji1Sg+8AXcvWncjyRJc X-Bogosity: Ham, tests=bogofilter, spamicity=0.130188, 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 13, 2025 at 7:06=E2=80=AFPM Gregory Price w= rote: > 5) Scarce resources > > We need to be careful not to consume excessive amounts of resources > in an attempt to track all these identifying mechanisms. Even 1 byte > per folio is 256MB on a 1TB machine. This gets out of hand quick. > > With task-work, I was able to add no additional resource consumption, > but deferring to a fully async scenario and needing to track things > like last-accessing CPU, timestamps, and etc. > > We'll need to examine this closely if we decide to aggregate either > of these mechanisms. My concern with physical address space monitoring is fragmentation. I ran some numbers on a few prod machines. Grouping by regions with the same memcg and ignoring any unmapped memory to be generous, machines with higher utilization can have a region/total pages ratio of ~40%, and even those with lower utilization (<50%) can also reach 20%. Accurately tracking these regions would require quite the region metadata, on the order of GBs.