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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D047DE674BE for ; Mon, 22 Dec 2025 14:59:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type:MIME-Version: Message-ID:Date:References:In-Reply-To:Subject:Cc:To:From:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=RI6wkzq9art1PUr+oZHEIShCAnFL/nfJWig5oY9a9H4=; b=k6u9OYFjudPN1EnugQHzb4JR4t 8uUdqRhFrcvzCuScSkBZ4q8Cs5HKRuCO1EqOY/g5lcVXjLUWEb4SMN8fK+oYX1zutgjj/haCseaIG UJfXexWscYcPx83D1UARlY7TnyZZVH2ZIsap2mKim8dQ4JMaS1V5QhT8TcpP2/03n3PvNNBrqeu+t fV0wdvYYCIfVntUcCZmKGTzGdR2dQvndd7JK1FFy5+wzeVr5N+r2tJWsE1FAysplDvPflUZdyRE6g xBYHfAWKqVvKELCR8DqH2EGoqlX++OmGmCloQQGD5ixK31v1eShdOlP2e142f2gSBRqXcALXw0yo0 meJuqC/w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vXhNC-0000000DszK-0SKe; Mon, 22 Dec 2025 14:58:58 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vXhN9-0000000Dsyd-17An for kexec@lists.infradead.org; Mon, 22 Dec 2025 14:58:56 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id E756740684; Mon, 22 Dec 2025 14:58:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 95BA5C4CEF1; Mon, 22 Dec 2025 14:58:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1766415533; bh=b4wwckHCSEHA9/WsH/82v8iyuGooOfYc2si289h0qdk=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=Sf8cvv973Ocy86SIfrhCawHgAShUAwMSVQXJmWzuodPbT41k1EQD8ytVx625GsbjA SW8CeuEhVcF9igA8P6YYwwKKILnQ4wtjZ9NJUZC8GVOJy1YFzowIKCHG9Wpke6Cd3p 4hlh6ZLKMflh9K4G4Fn2woo7rNi6d3jEcqdrNbRMhKV4lClYGgNb/eEA1oF9C9q53H PjiLu8ZRc9IoV32IPqFBobyygCnl0aDln4g75qhv3K1GZNkghCwfXPs4qohTcHGSXW Mqh2ghyKhw/orybk4h09OSXMzd0E0OMiPtbla5X7ljWCIHF1WJ1K2PrewNZlPqPMoN ptWtwVifEgDeQ== From: Pratyush Yadav To: Pasha Tatashin Cc: Pratyush Yadav , Mike Rapoport , Andrew Morton , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Muchun Song , Oscar Salvador , Alexander Graf , David Matlack , David Rientjes , Jason Gunthorpe , Samiullah Khawaja , Vipin Sharma , Zhu Yanjun , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, kexec@lists.infradead.org Subject: Re: [RFC PATCH 04/10] liveupdate: flb: allow getting FLB data in early boot In-Reply-To: (Pasha Tatashin's message of "Sat, 20 Dec 2025 10:11:34 -0500") References: <20251206230222.853493-1-pratyush@kernel.org> <20251206230222.853493-5-pratyush@kernel.org> <86wm2hj0ky.fsf@kernel.org> Date: Mon, 22 Dec 2025 23:58:43 +0900 Message-ID: <86o6nqd0m4.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251222_065855_364699_5D745EB9 X-CRM114-Status: GOOD ( 21.83 ) X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" Errors-To: kexec-bounces+kexec=archiver.kernel.org@lists.infradead.org On Sat, Dec 20 2025, Pasha Tatashin wrote: >> > [Follow-up from LPC discussion] >> > >> > This patch is not needed, you can use liveupdate_flb_get_incoming() >> > directly in early boot. The main concern is that we take mutex in that >> > function, but that I think is safe. The might_sleep() has the proper >> > handling to be called early in boot, it has "system_state == >> > SYSTEM_BOOTING" check to silence warning during boot. >> >> Right. I will give it a try. For hugetlb, this works fine since it >> doesn't really need to do much in FLB retrieve anyway, it just needs to >> parse some data structures. >> >> If other subsystems end up needing a two-part retrieve, one in early >> boot and one later, then I think it would be a good idea to model that >> properly instead of leaving it up to the subsystem to manage it. >> >> Anyway, that isn't a real problem today so let's look at it when it does >> show up. > > FLB has exactly one .retrieve() lifecycle event. Once called, the data > is considered fully available and cached in private->incoming.obj. > > If a subsystem has a requirement where it needs a specific state > available very early and other state available much later, the clean > solution is simply to register two separate FLBs. Hmm, that can work too. Anyway, let's figure that out when there is a real use case. For now, the current FLB design works fine. -- Regards, Pratyush Yadav