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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1767111368; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=2TX26TM650mDKkRro/fXnbl+XLoQ1USQ4BfmC9rVVJw=; b=j6PaJFGdfiv/UlefYkdloyimLIScBNCv4Fq/As7ICnPfZxSIFhR8TL3JAx4iMG+SErNU8z GL/g3R4ricymAW9pJMKONuYxXmE0MlD1+/i5b0MhAnpsUNNVDJH/A8YsXVimV9LW+gYFe9 4dCH/lY2Tv2yMLDbtO6x1z+OTO6xThg= 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-Rspamd-Queue-Id: CEF7A40017 X-Rspamd-Server: rspam03 X-Stat-Signature: bp1k46fjfamunoshw8xtz9gfbihoruk1 X-Rspam-User: X-HE-Tag: 1767111368-289220 X-HE-Meta: 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, 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 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.