From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 3DAA22DFA46 for ; Tue, 30 Dec 2025 16:16:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767111368; cv=none; b=aH05wtFEQS3pOoZ4LivJ7RFHjPTSfvL8EsQFHCHdysmlsJBLhC0T4awODg9iTXTI6ECRUWhCzCCTABI6WQ+8EhiKN7VYElUFKYy6a+1feUazkIqe0R4pmxdo6WabFxDM5nP+/hGc0M3fPBBFfv1vLxhZgHgJ4RFq8DVhLSEj4KQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767111368; c=relaxed/simple; bh=HlcNLtyf8O/u0mMEhZMir3AIamz/dUTwsMWTaLGExRU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WMfhp8VKZiz5Mj74K1qkYeMRf/LJa+NdeUsI2/+OUUSUyX0ZkuboXYkmGwcb9ewyE9O4hcQjtaQ2psibGORWBvVQ59zXg2uGVQ4tO8YL/JCX+5Bd0G4WOdrt6+71j0YLURZB1rCPuaOC5n8LrK8ggeIsxowqPLoMJ3/HRO/B/tI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cG1OD7UH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cG1OD7UH" 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> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: 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.