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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 692D1C982FA for ; Tue, 22 Sep 2026 15:20:55 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5B96A6B0096; Tue, 22 Sep 2026 11:20:54 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 56A666B0098; Tue, 22 Sep 2026 11:20:54 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 458366B009D; Tue, 22 Sep 2026 11:20:54 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 157266B0096 for ; Tue, 22 Sep 2026 11:20:54 -0400 (EDT) Received: from smtpin19.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 9CA30140536 for ; Tue, 22 Sep 2026 15:20:53 +0000 (UTC) X-FDA: 85241760786.19.ED352BB Received: from mail-qk2-f12.google.com (mail-qk2-f12.google.com [74.125.230.204]) by imf10.hostedemail.com (Postfix) with ESMTP id B244EC000F for ; Tue, 22 Sep 2026 15:20:51 +0000 (UTC) Authentication-Results: imf10.hostedemail.com; dkim=pass header.d=gourry.net header.s=google header.b=RJQmClJj; spf=pass (imf10.hostedemail.com: domain of gourry@gourry.net designates 74.125.230.204 as permitted sender) smtp.mailfrom=gourry@gourry.net; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1790090451; 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=1GRx/g24FB4lP9hKxncW6XGKAeFROn+FyWjD+Llh4VI=; b=PcHghcW2OrGEf1QWOTTLBDZiR2d+hCSb0eA8lCqsuYoJ3ZXV9uYHwbQhkg65hSfo1psGSU 8NzP0Ol+KvvGWwL/hLPrB3dS1UXhUoTKRVD8iZixZZ3DMTRUcNj4zCRZ/l21/PQ2Hi/L5A AefbjS62ZdCApVLPLY3Xu2/3VSEwQzs= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1790090451; b=ANfvr+d4NuW9oJZwm2+nBZwFd/FUjmHjgceDwUCZwmYOkXPyJCLCrGDahGzy/U/ssYRKBP Hebn+NQx8fwOsQj4GIAoFMcN1xyA/ZKR9l7lIdLcTvyDc74H06reThgvA2BpSmU2eWc13N 0vmsis6v6B4TftN8Wlabr3Sxrgmg8Ic= ARC-Authentication-Results: i=1; imf10.hostedemail.com; dkim=pass header.d=gourry.net header.s=google header.b=RJQmClJj; spf=pass (imf10.hostedemail.com: domain of gourry@gourry.net designates 74.125.230.204 as permitted sender) smtp.mailfrom=gourry@gourry.net; dmarc=none Received: by mail-qk2-f12.google.com with SMTP id af79cd13be357-939109fafd6so3191585a.3 for ; Tue, 22 Sep 2026 08:20:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gourry.net; s=google; t=1790090451; x=1790695251; darn=kvack.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=1GRx/g24FB4lP9hKxncW6XGKAeFROn+FyWjD+Llh4VI=; b=RJQmClJjqXBzrTi5LoAxmQAMjV6C2pRTblMznK2q9G4nbyQwR+e9CwezW5OTT/XUL6 4eWafaY+dv12fkkPR2UEqcLupSdTdbOvkxPqnMQEZ+czdY/3c87kspfCpkwgxuHoUaLp 0Qrh1bTXXhVxWvmp5wyR8QljiwTfvPavo1Hc8x6O/xDFC1GnFPdeaU92kI6f7q8eux4X r/csXLmRIeQXY71F0eyzTq2CscZ+kjX6Rky41F54YwKorjjYdZbfPnUUh97m5xuykuyu fdoSu8PKZ9brphRt4qmNeKsK+Zq8gxR84H5TlTTEVBZIvXWaDA2OATKFhsvkKMT7vzgD OlWw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790090451; x=1790695251; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=1GRx/g24FB4lP9hKxncW6XGKAeFROn+FyWjD+Llh4VI=; b=Woo9YV3XEJbpo6Sdv2vbs+qbJ4USQl6MuYu4cZ+o+f5RkP4V6avOypyvgTSwOQ0dce rKuqB7ME1VxNNcXr7WpgJj4gq6EvZf8qwdsEDgeoo0imCq5yiPrSp45cLIUZi475oj+i FsPCxRsrlPlANGBT2PNA1ZCBbs+vJq/vFqSq8w/5BzOC+2H1k3UKu5bWtDjJyJwgfmJR 1tVPu1x3XW86HupNbDI9le81oA+h1LRBnWyNl43TCeJrFDdjUYgx5atJjpM/pXycP0uX Z2UHAXrUjkt/wtr9bxbX+JhiPG22uW7Y8v/9acVUKMioxNrNYMlchxcD+8VPnbNlARLa 0NKA== X-Forwarded-Encrypted: i=1; AKwUvByFd9etbHGf/Fb6sida2QUbw21aQ59kUksvZBfqyfrBmOtnvoLL4gyzr6vc24dc5VIbaMUEY1hjdQ==@kvack.org X-Gm-Message-State: AFuF++lk05DsZLqKTEArfG9vTZdFD2vyUQgM/6PNeqmIks5Xit9S1qny S8jS5S34Vdw06ShOO7I916hfb5LFCKZPad0ZXPZbww0ylCf/BfNaoE3fgkwq7nB5JP4= X-Gm-Gg: AYBFou3brnQdUEIt1DQDVKdiPAH54WfjptSmYmg6N8Z2Z184Ys158q6Pupta4Hj0K9O HDsK8dq6/DDRznxqpIO9b3qQOpuKqV6yi06VQlP6rJA4/VR9sNf/7BGOUlttTJi3qhxYVU+ui6K rrFJiTqlvsAFeHKlICBnbaNdENfzyQXq9YdXvFLGqXXfzyHeOA2qBZOEVb5HXHcP9pZV7qCvFjw 4V9cE+kPMfvCM9kaTjeOM+QamVJ4ZONp+TJQgRpdDXk6krHA+G3Z0WQ7CUyzmKFDe0JqVdEQ51p euKqeeREdvgZpHrHPC89PHRgpk9nZ+/nzXMUuzA2YdI4vpt3Wjt6pAXooZ2GUzcSQPWhxG4g74M ppdEBOouaiiHDoGmQS6GVkGDCXbCQ9wIhva719dQ4l8sG96pD5S6hsjd5sJKbbjxbiAbsAOYIKi bKdi6ZzXLSJrmje5/K/QjIO3A3HZfnwvF55eK0xvfvebkxg7J90UCTtAjhx01M5Q7oFnoy5wN96 rlrI+IpFUTcsqh5N0ooUIYXR2u5QvLBX9R0cG8YjwYrEQTdbTBSUe0= X-Received: by 2002:a05:620a:280f:b0:93b:e9d2:5ece with SMTP id af79cd13be357-93c15e412a9mr594708785a.39.1790090450524; Tue, 22 Sep 2026 08:20:50 -0700 (PDT) Received: from gourry-fedora-PF4VCD3F (pool-173-79-60-52.washdc.fios.verizon.net. [173.79.60.52]) by smtp.gmail.com with ESMTPSA id af79cd13be357-93c1cf0dcd9sm181244085a.4.2026.09.22.08.20.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Sep 2026 08:20:49 -0700 (PDT) Date: Tue, 22 Sep 2026 11:20:47 -0400 From: Gregory Price To: Chris Li Cc: Rik van Riel , Johannes Weiner , Baoquan He , Nhat Pham , Kairui Song , Michal Hocko , Roman Gushchin , Shakeel Butt , Yosry Ahmed , David Hildenbrand , Muchun Song , Kemeng Shi , Barry Song , YoungJun Park , Chengming Zhou , "Lorenzo Stoakes (Oracle)" , "Liam R. Howlett" , "Vlastimil Babka (SUSE)" , Mike Rapoport , Suren =?utf-8?B?QmFnaGRhc2FyeWFu77+8?= , Qi Zheng , Axel Rasmussen , Yuanchu Xie , Wei Xu , Wenchao Hao , Jonathan Corbet , Hugh Dickins , Baolin Wang , Tejun Heo , Michal =?utf-8?Q?Koutn=C3=BD?= , Shuah Khan , Kunwu Chan , Meta kernel team , Linux Memory Management List , Linux Kernel Mailing List , linux-doc@vger.kernel.org, "open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)" , Andrew Morton , Kairui Song , Joshua Hahn Subject: Re: Path forward for Virtualized Swap? Message-ID: References: <785353ef79844e81a8cd97e87b00ef1f785b15e5.camel@surriel.com> <83539be885f15bb567b30264f5f62e718f4a9fd0.camel@surriel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Stat-Signature: ncr93udothbuwqxkpo8wkonwmuuyqmsb X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: B244EC000F X-HE-Tag: 1790090451-39247 X-HE-Meta: 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 PMlefy3s b4xbzIkrjT0IuVbYzXgseSfKxOXfFp3xWNVptnC4aQj7ostEm0iJYX7wcHRSvh3MbvO3QB7RbGOJlj5R65Ik1MgJS3P2FW0P3bdNkq6B8c2ZXZiOF0terdtYEp6GPz36Ln1P/1ATeJy69YcJRGcWsAN0P2BobI9O6NukogJuztUXj8mAzwEiHoyy0OxrLNupXxUikV8kYscSevdtGe66c1US3A0HA2eDbphvd7+atUuWrfLGHo9bvEoEFu+Z6SncnOAuder2hC9z690+L/0GSByeeowbpVB1fgq+cs/e+hGJlbv+XyddHcypLjpDEvP49gFKuoq1jo48jT088Fwl6FuTqF7G31zzwdFHJjuMBGFYs/DO8yoXkZQ+vi1OGvTLoq+WvXS6l7Xrmy9xEjE05fFPyMZlDVMA61MYOdzmX90q5PoRkrRI/0G6GVyLmv7BL0yI7 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Sep 22, 2026 at 03:32:44AM -1000, Chris Li wrote: > > Right now it has 64GB of memory. > > That is exactly my point. You are running 1/8 = 12.5% system ram. > Chris you are missing the point Zswap: 8812236 kB Zswapped: 24927876 kB To support this, you'd need to know you were going to get a 3:1 compression ratio and allocate 24GB of storage (24GB of swap slots). An hour from now he might run a workload that's 4:1 compressible and there would be 32GB zswapped - but if he'd only allocated 24GB of swap he'd be limited to 24GB arbitrarily. On a 1.5 TB server, that number is oppressive. It's 192GB of potentially dead storage space. At 1 million servers that up to 183 Petabytes of pointless provisioned flash if you know that most of the memory is zswappable. You're focused on the wrong problem. ~Gregory