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 6C3E1C0218D for ; Sun, 26 Jan 2025 20:04:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DED91280108; Sun, 26 Jan 2025 15:04:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D9CEB280101; Sun, 26 Jan 2025 15:04:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C64A8280108; Sun, 26 Jan 2025 15:04:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id A7698280101 for ; Sun, 26 Jan 2025 15:04:09 -0500 (EST) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 33A974B8DE for ; Sun, 26 Jan 2025 20:04:09 +0000 (UTC) X-FDA: 83050679418.03.8C241DB Received: from mail-qv1-f50.google.com (mail-qv1-f50.google.com [209.85.219.50]) by imf01.hostedemail.com (Postfix) with ESMTP id 3574040011 for ; Sun, 26 Jan 2025 20:04:07 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=ziepe.ca header.s=google header.b="j/dN7iQ4"; spf=pass (imf01.hostedemail.com: domain of jgg@ziepe.ca designates 209.85.219.50 as permitted sender) smtp.mailfrom=jgg@ziepe.ca; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1737921847; 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=tqmZpJa6XKK6XwhZVOqs5mOmSw08uomiMPwiIc01beQ=; b=YIAFTLu0faNn7yBES+hmW3Xx66IMbriBqwkxZsyKNQfTKzC7leb8O8F/2jVR8zlI/qznOl l3nK4Y5XsjNSgww5cejsPMqzE7KY5qQwZT5ONhZkidgsT0PVXrgl/3lNbvAX8DNTeHUi+5 mqN7n0hNRYtaH6nPuhAaV2ctliGyhOU= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=ziepe.ca header.s=google header.b="j/dN7iQ4"; spf=pass (imf01.hostedemail.com: domain of jgg@ziepe.ca designates 209.85.219.50 as permitted sender) smtp.mailfrom=jgg@ziepe.ca; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1737921847; a=rsa-sha256; cv=none; b=LEowCVCSJJuDZj1oOfrTS3BDeyLkQ5mfE0Sqhuam6ye27PokFe2/o2rJKCM33D1uB6Qqfb HYwltunIvv65ktrSFz8Hg0XKaifBQEgDT0xAn8Kd8a2EbZafRtEonNTVyK2q3dOpl3alPc XGGY0EYOeuYtiWsqlUz8zA/EQ3tPvXA= Received: by mail-qv1-f50.google.com with SMTP id 6a1803df08f44-6dce7263beaso36429686d6.3 for ; Sun, 26 Jan 2025 12:04:06 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1737921846; x=1738526646; darn=kvack.org; 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=tqmZpJa6XKK6XwhZVOqs5mOmSw08uomiMPwiIc01beQ=; b=j/dN7iQ4dDChUmCJksSok3KDbxgF2LIJto2SQcdTQyO2Eqw13Cqfixukx+4HyZdMhn mTnrXP3xX0JpC1dolXcewO5UJDk46E4OX8GhFWD63rTyQNqt9KabvTEohiSFt35lpfvc jr6ZVzIECuxawQf/d4JmdsBFJTbUyvs0GvMoCfirf+85TrkB9hg2C8d97ee5rfhyv2TB TvCia/8wkPVaLuzEmPEX2ewQJuxZHnmcg+PWsCi+MIlhJUTBw2fR8jxuzvYtEjP16xtN lWjyOxUJQLsG7+qSdto+8DZXmb9EbBb2G0P/TParJyVEIH4a9kVnbA02gJvL396gy/oU 2mjg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1737921846; x=1738526646; 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=tqmZpJa6XKK6XwhZVOqs5mOmSw08uomiMPwiIc01beQ=; b=CEwvDPaXlVuvxee1IeTz2HgVG/o8Xoezt4LawJjLareof3Vc4bwkmbvjhQTPHzxt2i 6AT8lYM9NJt+7iPQcRqAfgrVHsgxgCygt9swIuRnEIoVZ72KJxKsng5/y1z2z9+pZ75a 9e4qwLqBuQ5WPfnNW9cES+AxNQozPxhtLd6uvLeRue6SAfFnveE8LkowX0Fcx3haOqYq sSNbi305ymbtOTS2NyNgGFStJLWbb3IMH+GgyCWaZfy0RudkrIancxHZLVk12hRq1eQi /d0JDYeo5YK6MdG5mjXeCLf2ODP/JGHbQj5l7JaoXabMFc02Hr+fH/nRkZj1cJwM85Pe ASyw== X-Forwarded-Encrypted: i=1; AJvYcCU+wcBxP42BNy+s0Si5HBA7IbkMzvnY2Z2P45eW8D8br0D2aXUoftcCFmMQb3jHrPKYJvEIjL0SLg==@kvack.org X-Gm-Message-State: AOJu0Yz101IY/cFPixWleL+ngCfZpim2CN/PI//g/TgT4yTY7+GJisUh +SG3iRQ2PUbg0fOjEEjvbWfVDGZ1ftUp14wsjnpXFAwHoviGvnRXT6c3/MXyo0M= X-Gm-Gg: ASbGncuzp7yvtUHPjmoHGjTPj0O0Pag3C6kdII9aqrq5iLcbPEaXecI3pKdLd+ZmhfS 8nvBZWfeUW25ttFw69OBz18eJMc/4WTOikIM9qF7kEDiiM9pkrVogqQ/SDoVlmEW0cLAyLKgGqU VzvW0SLFJYmdxG1DQVwHhKe2VFdYTPDIuiJ9jYi+ajPnpUF93IsYXv9yzHuY3N3bPZJcZKhEq9W 20APZGY7qYYR5b9Gg05SfidhraQ0b7rbiCr4Wxaqob1n7DjRcnwhuPHHTrAqyBAiDgu5PVclsy8 Ova17CMDREIwMMddFkafJmGsv4o7VlhLXLT67kjdjC/wsYd150a5rw== X-Google-Smtp-Source: AGHT+IHpnaT7HEHxk9kr5fNhqITFwNr9XHGqhuGmpa862DNvtiHUF+PwpguQKGRDSAxczezF1/yjWw== X-Received: by 2002:ad4:596c:0:b0:6d8:aa52:74a3 with SMTP id 6a1803df08f44-6e1b2213f57mr592223376d6.28.1737921846246; Sun, 26 Jan 2025 12:04:06 -0800 (PST) Received: from ziepe.ca (hlfxns017vw-142-68-128-5.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.68.128.5]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-46e66b67bc3sm31665181cf.52.2025.01.26.12.04.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Jan 2025 12:04:05 -0800 (PST) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1tc8rU-00000005FI5-1r6P; Sun, 26 Jan 2025 16:04:04 -0400 Date: Sun, 26 Jan 2025 16:04:04 -0400 From: Jason Gunthorpe To: Pasha Tatashin Cc: Mike Rapoport , David Rientjes , lsf-pc@lists.linux-foundation.org, Alexander Graf , "Gowans, James" , linux-mm@kvack.org Subject: Re: [LSF/MM/BPF TOPIC] memory persistence over kexec Message-ID: <20250126200404.GA1103620@ziepe.ca> References: <20250120141427.GK674319@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 3574040011 X-Stat-Signature: 6bk6bm7z6eigzm6xi3fqfikyftsxstet X-Rspam-User: X-HE-Tag: 1737921847-109394 X-HE-Meta: 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 /L0952q+ nWa9jXRfm6820ia/4u6/OEOE9FjseZ4xrzocU5+Dm6jMpQvceGO0VvxeT/scl6ko+sTo+SbA8FGIwZk9mKpJ06G244/fqQt7UPlDi2I5wR15ipGSBfzCzanoH6eRMtaWn892Rvesy0EIlgpGFeKN7sSmQ+zM5UuBvmXyNdr6wF6LL4qRqRyQcYsyBcLP0YBnIZa2Fsz2qYXKMwSxmG112WN+tznpJu277Z62O0vsMV6qKW2EsTrnxiqqmp15ckYCVqbDIkWIDqvNA+FWZnsDS09ddG3PpSklcGVyN X-Bogosity: Ham, tests=bogofilter, spamicity=0.078414, 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 Sat, Jan 25, 2025 at 10:19:51AM -0500, Pasha Tatashin wrote: > One way to solve that is pre-reserving space for the KHO tree - > ideally a reasonable amount, perhaps 32-64 MB and allocating it at > kexec load time. Why is there any weird limit? We are preserving hudreds of GB of pages backing the VM and more. There is endless memory being preserved across? So why are we trying to shoehorn a bunch of KHO stuff into the DT? Shouldn't the DT just have a small KHO info pointing to the real KHO memory in normal pages? Even if you want to re-use DT as some kind of serializing scheme in drivers the DT framework can let each driver build its own tree, serialize it to its own memory and then just link a pointer to that tree. Also, I'm not sure forcing using DT as a serializing scheme is a great idea. It is complicated and doesn't do that much to solve the complex versioning problem drivers face here.. Jason