From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 253932E6CB8; Tue, 22 Sep 2026 15:50:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=96.67.55.147 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790092208; cv=none; b=aL+eETtRmlSbh7EOlDXw4rZw5pBhSb7bi6eUicsvRcODkhyW96e8rycRnJY4kXzqxO4CmkZK382Uq9yfU7//kYGGG7LPi0fJaPHac/0qNGY1+DzgTyRmd4+5jH/FWSCFW4O/DCqwkxYj2ckW05YcL4cmlju9DT5Q8eiV4a+9kA4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790092208; c=relaxed/simple; bh=/bkJu23UOULz3yPDYNr6BuLm3UrRrVgL3Ir6c9UiC8w=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=Em36dJjp5E8+Me3b6rbsoHw6+MvQRmS/lXePE4na7kvn2HK3C1OZipIGbdcBpVBAt4bruXEdJvedftLGi794UhJyvhoxARLIwtc+3Bhc4bWB+6zmZD2hE3bRUB6Z1k//3CEocw+foLfQw7se2ZuXjzQ6p7YXcSELA6g6WIt9WcU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=surriel.com; spf=pass smtp.mailfrom=surriel.com; dkim=pass (2048-bit key) header.d=surriel.com header.i=@surriel.com header.b=JAbyvQXS; arc=none smtp.client-ip=96.67.55.147 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=surriel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=surriel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=surriel.com header.i=@surriel.com header.b="JAbyvQXS" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=surriel.com ; s=mail; h=MIME-Version:Content-Transfer-Encoding:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID; bh=6K3Ud4EKI3engeNS8qIUkp6OAKXd2y5YW5HabWOrebM=; b=JAbyvQ XSsMgjn0TEho6JwbjAC+6MlhZm3WuAyVwsdbjj/BiRvbJSHeQjI3bYRbF+LZjdLLYapYp2Tm6yzfg 1Yr6nkIUwU3z4mpwAts4tEMORWUQF9JrNLKy160v6+9xBb83yzqa9/Yh/TtiYyLjAT5ZDRYOXzWpt jpHhuA8UWbUXZ72zGeitYDGHuVD4jja4A/B2ZimNojNkNPgZl18cXb5SCt34DZsO8pC1W3ZLdvyIR cQXBWRZ7u2ALckyB/ahi1boUpuRHzHH9Jt238N4XCnoFResgML5BRwDrLBuaYjb8Yo0LCLf9m9nDv iUzFg5dH3p2uZo8/Bm5s4nz3m9MQ==; Received: from [2601:18c:8100:a0e0:5a47:caff:fe78:8708] by shelob.surriel.com with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.99.5) (envelope-from ) id 1x92jp-00000001ofN-0kte; Tue, 22 Sep 2026 15:48:57 +0000 Message-ID: <02616d611c9e862afc6c8c3118b6be096756b3bb.camel@surriel.com> Subject: Re: Path forward for Virtualized Swap? From: Rik van Riel To: Chris Li Cc: Gregory Price , 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?Q?Baghdasaryan=EF=BF=BC?= , Qi Zheng , Axel Rasmussen , Yuanchu Xie , Wei Xu , Wenchao Hao , Jonathan Corbet , Hugh Dickins , Baolin Wang , Tejun Heo , Michal =?ISO-8859-1?Q?Koutn=FD?= , 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 Date: Tue, 22 Sep 2026 11:48:56 -0400 In-Reply-To: References: <785353ef79844e81a8cd97e87b00ef1f785b15e5.camel@surriel.com> <83539be885f15bb567b30264f5f62e718f4a9fd0.camel@surriel.com> Autocrypt: addr=riel@surriel.com; prefer-encrypt=mutual; keydata=mQENBFIt3aUBCADCK0LicyCYyMa0E1lodCDUBf6G+6C5UXKG1jEYwQu49cc/gUBTTk33A eo2hjn4JinVaPF3zfZprnKMEGGv4dHvEOCPWiNhlz5RtqH3SKJllq2dpeMS9RqbMvDA36rlJIIo47 Z/nl6IA8MDhSqyqdnTY8z7LnQHqq16jAqwo7Ll9qALXz4yG1ZdSCmo80VPetBZZPw7WMjo+1hByv/ lvdFnLfiQ52tayuuC1r9x2qZ/SYWd2M4p/f5CLmvG9UcnkbYFsKWz8bwOBWKg1PQcaYHLx06sHGdY dIDaeVvkIfMFwAprSo5EFU+aes2VB2ZjugOTbkkW2aPSWTRsBhPHhV6dABEBAAG0HlJpayB2YW4gU mllbCA8cmllbEByZWRoYXQuY29tPokBHwQwAQIACQUCW5LcVgIdIAAKCRDOed6ShMTeg05SB/986o gEgdq4byrtaBQKFg5LWfd8e+h+QzLOg/T8mSS3dJzFXe5JBOfvYg7Bj47xXi9I5sM+I9Lu9+1XVb/ r2rGJrU1DwA09TnmyFtK76bgMF0sBEh1ECILYNQTEIemzNFwOWLZZlEhZFRJsZyX+mtEp/WQIygHV WjwuP69VJw+fPQvLOGn4j8W9QXuvhha7u1QJ7mYx4dLGHrZlHdwDsqpvWsW+3rsIqs1BBe5/Itz9o 6y9gLNtQzwmSDioV8KhF85VmYInslhv5tUtMEppfdTLyX4SUKh8ftNIVmH9mXyRCZclSoa6IMd635 Jq1Pj2/Lp64tOzSvN5Y9zaiCc5FucXtB9SaWsgdmFuIFJpZWwgPHJpZWxAc3VycmllbC5jb20+iQE +BBMBAgAoBQJSLd2lAhsjBQkSzAMABgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRDOed6ShMTe g4PpB/0ZivKYFt0LaB22ssWUrBoeNWCP1NY/lkq2QbPhR3agLB7ZXI97PF2z/5QD9Fuy/FD/jddPx KRTvFCtHcEzTOcFjBmf52uqgt3U40H9GM++0IM0yHusd9EzlaWsbp09vsAV2DwdqS69x9RPbvE/Ne fO5subhocH76okcF/aQiQ+oj2j6LJZGBJBVigOHg+4zyzdDgKM+jp0bvDI51KQ4XfxV593OhvkS3z 3FPx0CE7l62WhWrieHyBblqvkTYgJ6dq4bsYpqxxGJOkQ47WpEUx6onH+rImWmPJbSYGhwBzTo0Mm G1Nb1qGPG+mTrSmJjDRxrwf1zjmYqQreWVSFEt26tBpSaWsgdmFuIFJpZWwgPHJpZWxAZmIuY29tP okBPgQTAQIAKAUCW5LbiAIbIwUJEswDAAYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQznneko TE3oOUEQgAsrGxjTC1bGtZyuvyQPcXclap11Ogib6rQywGYu6/Mnkbd6hbyY3wpdyQii/cas2S44N cQj8HkGv91JLVE24/Wt0gITPCH3rLVJJDGQxprHTVDs1t1RAbsbp0XTksZPCNWDGYIBo2aHDwErhI omYQ0Xluo1WBtH/UmHgirHvclsou1Ks9jyTxiPyUKRfae7GNOFiX99+ZlB27P3t8CjtSO831Ij0Ip QrfooZ21YVlUKw0Wy6Ll8EyefyrEYSh8KTm8dQj4O7xxvdg865TLeLpho5PwDRF+/mR3qi8CdGbkE c4pYZQO8UDXUN4S+pe0aTeTqlYw8rRHWF9TnvtpcNzZw== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.60.2 (3.60.2-1.fc44) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2026-09-22 at 05:23 -1000, Chris Li wrote: >=20 > > > > > > Zswap:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0 8812236 kB > > > > > > Zswapped:=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 24927876 kB >=20 > My original request was for the whole system: what percentage of the > total system RAM size has been swapped out to zswap. >=20 24.9 GB out of 64 GB is 28% That is how much application memory was swapped out to zswap. 12% is how much system memory is used by zswap. Those are two very different things, and it really is not clear to me which of the two you are talking about at what point in time. > My observation is that, even with zswap, when 100% of > system RAM is swapped out, the application suffers greatly. There is > a > reason why we only have 7-10% system RAM swapped out. You mean for your specific workload, you do not want more than 5-8 GB out of 64GB to be swapped out? That is perfectly acceptable. You should be able to configure that. However, your configuration values are not a good default for my setup. I believe we need to set the default to something that accommodates a diverse range of desktop and mobile users.=C2=A0 Most of those users do not know what they will need,=C2=A0 but they will know to close a few browser tabs when=C2=A0 things get slow. The companies running thousands of servers that are carefully managed, and which overwhelmingly have the same configuration values deployed to them are more than capable of setting the dozen or so config values their entire fleet might need. --=20 All Rights Reversed.