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 6CAA3EE4989 for ; Tue, 30 Dec 2025 16:16:13 +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:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=2TX26TM650mDKkRro/fXnbl+XLoQ1USQ4BfmC9rVVJw=; b=O3OAy2TaSRw6znY8yK1BszpB+q HlGSKxeWWmyQGbccPZv6m5EjiU2YtXSFTnaLYPymreRtdOufsM5QZJzvZ6Wn93sRaOZkYGN+FRPrL J2isG50mR7O+5tVflAayjBzouw1a5Qwgv8u8jGOv0s5ErB8Vga7wEBayCQQPqV6OkAysqoRjQget8 GUVQKKJFEqd+QG/FTEGNc3YkAh0tPXHd2FAlwKNrxyUMxi4/h+IQLbF0IRjtyQD7Egd5V4OcpIbTa LTrmSked372yBUSWQ4c6KVwVzjSPZNkTBumWtD26Ap+DM5wa7l8A26UKTUifhzMKV2t1KzQU3WHLt +7+Z2p+A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1vacOI-000000052sv-3kc5; Tue, 30 Dec 2025 16:16:10 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1vacOG-000000052rs-2BuB for kexec@lists.infradead.org; Tue, 30 Dec 2025 16:16:09 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id D4577405D6; Tue, 30 Dec 2025 16:16:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 90A5FC4CEFB; Tue, 30 Dec 2025 16:16:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767111367; bh=HlcNLtyf8O/u0mMEhZMir3AIamz/dUTwsMWTaLGExRU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cG1OD7UHqRWnRx0c3h5AWJz/OZ1xiYrNSHTEElBM2TXQmtHr7iXURNccCaodth9rG 5xiCAPvXL10s98nPJB76VFOlqFQTDARqp0lgbAbcfHwEx6nz0akAxOV+TAiNP3eyUK in6KMbJe/REScuCQ2skG7shtIuHzorsMdmbi64HmatTw+SlSFYP/UDLQCL4ittiUNA Zq60DhS0GLjGM8Vv21SwVWzC3p8hVztq+yqkrniB/3rvAtg0uimL+/HUuMsXRavNYf R3qWNUI/KAimLiCv2xu+h7K0m92N5pDO8TosTzLnzw6QN9AeTo3W0+g+3YzfYn5C4v QElwDP1hpWUJg== Date: Tue, 30 Dec 2025 18:16:00 +0200 From: Mike Rapoport To: Pasha Tatashin Cc: Pratyush Yadav , Evangelos Petrongonas , Alexander Graf , Andrew Morton , Jason Miu , linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-mm@kvack.org, nh-open-source@amazon.com Subject: Re: [PATCH] kho: add support for deferred struct page init Message-ID: References: <861pkpkffh.fsf@kernel.org> <86jyyecyzh.fsf@kernel.org> <863452cwns.fsf@kernel.org> <864ip99f1a.fsf@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20251230_081608_577050_992413A2 X-CRM114-Status: GOOD ( 14.94 ) 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 Tue, Dec 30, 2025 at 11:05:05AM -0500, Pasha Tatashin wrote: > On Mon, Dec 29, 2025 at 4:03 PM Pratyush Yadav wrote: > > > > The magic is purely sanity checking. It is not used to decide anything > > other than to make sure this is actually a KHO page. I don't intend to > > change that. My point is, if we make sure the KHO pages are properly > > initialized during MM init, then restoring can actually be a very cheap > > operation, where you only do the sanity checking. You can even put the > > magic check behind CONFIG_KEXEC_HANDOVER_DEBUG if you want, but I think > > it is useful enough to keep in production systems too. > > It is part of a critical hotpath during blackout, should really be > behind CONFIG_KEXEC_HANDOVER_DEBUG Do you have the numbers? ;-) -- Sincerely yours, Mike.