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 02CB138A718 for ; Fri, 20 Mar 2026 10:24:12 +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=1774002253; cv=none; b=grVXrlclrLL5cG0ag3mQaHvEbbK2JFjlu0Z4C5XoJguSWGf/6+DFVUSCZtStmaNDI47QN8IhByo45GIn+quEmwwVILm1CubrX5RVx4QaUO1PuQl8mIflDg1q5RFhFxCtAxR3o4PKw23VucUWLHDFoHbnmJ5pJ3OnRhVFPhXgqg0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774002253; c=relaxed/simple; bh=Wn5jstUr6dOBAVU09O9JpAI9Bd4XixCEsjnU1Cfj78w=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=r/cBhhFDqF9ZpYDDS16B0Cx72hOtRCHmey/T+yiaGQq+eVVn9c2WPZZzs+81GKmxeNOQvUWSkSlx/7qDuaXlK/BEcad4jt3R/rCSiW/vepPJ8ETul0wnuHBSk8qf/fbQHp0saeS1ISWW+I8htar+EKojkamwdrwIokGWNM8l7W0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=L9ltC+2P; 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="L9ltC+2P" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ADDF9C4CEF7; Fri, 20 Mar 2026 10:24:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774002252; bh=Wn5jstUr6dOBAVU09O9JpAI9Bd4XixCEsjnU1Cfj78w=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=L9ltC+2PmAsjD6RD3FhjaLQ88mtFPqKCZ5e5wnXlbMD0IE9ci1RMSYc2iX7AMzX2x FjYVkT+gjdl/yDn4ixlebZZ+2qW2aDJguNj3A/VBCQP9agUS4lHl8yk0KWw9VvMIXO J7vr5Wg3QsfH7xzwVn0AgUtwCcaD/g2GsqkxKns3rKpMmSp2LxSdLI2Z4E9rk+133W JG7fXKrDdeY4Z1Ksm/FRtx1S1+r14I/wUqQVqO6Ge7JvNdImtPHqNsEPwMm2rZUfJv uOkHS/OYVXSHVS3P/53PHq+FigYnABJvBNjGBfIb924tCSOAW91pKd6lCAKkX/1ygE hJ3HQ35zk27RA== From: Pratyush Yadav To: Mike Rapoport Cc: Pratyush Yadav , Alexander Graf , Pasha Tatashin , Andrew Morton , kexec@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/2] kho: drop restriction on maximum page order In-Reply-To: (Mike Rapoport's message of "Tue, 17 Mar 2026 13:04:15 +0200") References: <20260309123410.382308-1-pratyush@kernel.org> <20260309123410.382308-2-pratyush@kernel.org> <2vxzo6kmddl8.fsf@kernel.org> Date: Fri, 20 Mar 2026 10:24:08 +0000 Message-ID: <2vxzy0jmajef.fsf@kernel.org> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain On Tue, Mar 17 2026, Mike Rapoport wrote: > On Tue, Mar 17, 2026 at 09:12:19AM +0000, Pratyush Yadav wrote: >> On Tue, Mar 10 2026, Mike Rapoport wrote: >> >> > On Mon, Mar 09, 2026 at 12:34:07PM +0000, Pratyush Yadav wrote: >> >> KHO currently restricts the maximum order of a restored page to the >> >> maximum order supported by the buddy allocator. While this works fine >> >> for much of the data passed across kexec, it is possible to have pages >> >> larger than MAX_PAGE_ORDER. >> >> >> >> For one, it is possible to get a larger order when using >> >> kho_preserve_pages() if the number of pages is large enough, since it >> >> tries to combine multiple aligned 0-order preservations into one higher >> >> order preservation. >> >> >> >> For another, upcoming support for hugepages can have gigantic hugepages >> >> being preserved over KHO. >> >> >> >> There is no real reason for this limit. The KHO preservation machinery >> >> can handle any page order. Remove this artificial restriction on max >> >> page order. >> >> >> >> Signed-off-by: Pratyush Yadav >> >> Signed-off-by: Pratyush Yadav (Google) >> > >> > One SOB should be enough ;-) >> >> Hmm, I figured the unemployed me (who originally wrote the patch) and >> the employed-by-google me (who is doing this new version) would count as >> two separate entities and there should be a S-o-b for both. > > Maybe than something like: > > Signed-off-by: Pratyush Yadav (Hobbyist) > Signed-off-by: Pratyush Yadav (Google) > > ;-) > Yeah, that works too :-) I'll use that when I redo some of the HugeTLB patches too -- Regards, Pratyush Yadav