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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 08F58C5AD4C for ; Thu, 23 Nov 2023 10:19:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344554AbjKWKTF (ORCPT ); Thu, 23 Nov 2023 05:19:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53872 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232291AbjKWKTC (ORCPT ); Thu, 23 Nov 2023 05:19:02 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C449A9F for ; Thu, 23 Nov 2023 02:19:08 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id E095FC433C7; Thu, 23 Nov 2023 10:19:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1700734748; bh=BIsZoyFkGqybSMp8LsFEV/t0sEtZKTYGcLF/WgdEU8A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BfisG42wNKSu3613Sr6vuiVrQghiiyZTRf7R1sFUOw1Oha90RgZu8eBFpTxci+zF1 agbbICZLrwQfHlza87s+C4NXEcoif+I8cE/Uql2TVYmm03S+sncf7anWPLPm9epCcW b8NvfnciZgPu9yLK1bBbA7oWJfble2vM5hsF4SB1DIHmjv4XRW784yDrPu7L5vu7eA rdFN0/essbPCun0V4WMDFBMNofYDMYllC1dWxjXHV0nS+4ZMoEdvncJ40jsOmz83pZ A2YiFWVDVNq1DNhvUvopxNOLIIgwS91e6CfYOORHvJZi2r0qtc0dEDCJS1Tuwfggng nrgAVeuDrFwnA== Date: Thu, 23 Nov 2023 12:18:54 +0200 From: Mike Rapoport To: Serge Semin Cc: Thomas Bogendoerfer , Andrew Morton , Matthew Wilcox , Alexey Malahov , Arnd Bergmann , Aleksandar Rikalo , Aleksandar Rikalo , Dragan Mladjenovic , Chao-ying Fu , Jiaxun Yang , Yinglu Yang , Tiezhu Yang , Marc Zyngier , linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/7] mm/mm_init.c: Extend init unavailable range doc info Message-ID: <20231123101854.GF636165@kernel.org> References: <20231122182419.30633-1-fancer.lancer@gmail.com> <20231122182419.30633-6-fancer.lancer@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20231122182419.30633-6-fancer.lancer@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Serge, On Wed, Nov 22, 2023 at 09:24:03PM +0300, Serge Semin wrote: > Besides of the already described reasons the pages backended memory holes > might be persistent due to having memory mapped IO spaces behind those > ranges in the framework of flatmem kernel config. Add such note to the > init_unavailable_range() method kdoc in order to point out to one more > reason of having the function executed for such regions. > > Signed-off-by: Serge Semin > > --- > > Please let me know if the IO-space pages must be initialized somehow > differently rather relying on free_area_init() executing the > init_unavailable_range() method. Maybe I'm missing something, but why do you need struct pages in the IO space? > --- > mm/mm_init.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/mm/mm_init.c b/mm/mm_init.c > index 077bfe393b5e..3fa33e2d32ba 100644 > --- a/mm/mm_init.c > +++ b/mm/mm_init.c > @@ -796,6 +796,7 @@ overlap_memmap_init(unsigned long zone, unsigned long *pfn) > * - physical memory bank size is not necessarily the exact multiple of the > * arbitrary section size > * - early reserved memory may not be listed in memblock.memory > + * - memory mapped IO space > * - memory layouts defined with memmap= kernel parameter may not align > * nicely with memmap sections > * > -- > 2.42.1 > -- Sincerely yours, Mike.