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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 52908CD4853 for ; Wed, 4 Sep 2024 15:41:03 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D96888D0250; Wed, 4 Sep 2024 11:41:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D1FA56B0447; Wed, 4 Sep 2024 11:41:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B99198D0250; Wed, 4 Sep 2024 11:41:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 97DF96B0445 for ; Wed, 4 Sep 2024 11:41:02 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 57F0A806E7 for ; Wed, 4 Sep 2024 15:41:02 +0000 (UTC) X-FDA: 82527469164.06.76B7040 Received: from nyc.source.kernel.org (nyc.source.kernel.org [147.75.193.91]) by imf21.hostedemail.com (Postfix) with ESMTP id C3B6A1C0020 for ; Wed, 4 Sep 2024 15:40:59 +0000 (UTC) Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=LnRbvL1B; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf21.hostedemail.com: domain of rppt@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1725464352; 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=LZL9HdBU3wYHL24VemCPKtng/K6McS6BpUz4HjwIMLo=; b=rnffz7B84fLpDIMtcAkFWkBjjXOjx2Am3B9ICGIuQUkDXVBb13l0Q1R7KpAznJtqkpYsuc Rd0MTE33ljZQaIAOi+zt2bkUdXO7MkSaRA8PYZ+67W7mn85us0PUopvB4Gkf/ZHEcBZa0g xZGAIQhRbfljZ9s/ZcEDYNDqBL+nReg= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1725464352; a=rsa-sha256; cv=none; b=D2GcW4Qyums7Ltm1DYM61vuLkqFKkG1+PMJoqB9rgvAhrEjl3xMXAvQlrHBn+YlnvgrQRw 1HibTFkGSZ8Sx7da+YB0jmm2md326e3oP4966vKLfQ1XXspQv3t8sHVnvDZbISiE65vjoG Ti+i+VTEUlJnMo/jgZaeb0J5BwRNn0s= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=LnRbvL1B; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf21.hostedemail.com: domain of rppt@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=rppt@kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id F0E03A44518; Wed, 4 Sep 2024 15:40:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 505F9C4CEC2; Wed, 4 Sep 2024 15:40:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725464458; bh=eBOFrT6g1MH/GsUkaWrL4ij93taIsUu6H4VISTRTlxQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=LnRbvL1BOCSeM9auP/uCAF73FuFEBTFTcIhhEylHe8QUOL4/QSUAkSdeV7eLxYIW6 sEuNToUWEZh7UndkaIy0oFtOOP25q8sMQg+QnVPQBbAHDazeO+W314f7AVPDV/dMVA KJlraCLUteg9zmL5liSstWNuEnx8+PMfJvr+BdhQYNeigY4y2YOtXqrPzfyqfs7Cz5 aSXgJTCEVdFaTNNGPNtv/NTsWuPjcLz2lDZ4Efz10/cJy4XhmGijIi5fjGqzew2V3o 3M6/2WvsXOYq/3tjtG2rLGOnMIS3EwmCGxbSg4sW340FtjlwFRejzwaCk3xDlWBABX y/PzHmndcVQnw== Date: Wed, 4 Sep 2024 18:38:11 +0300 From: Mike Rapoport To: Rong Qianfeng <11065417@vivo.com> Cc: Mel Gorman , vbabka@suse.cz, Andrew Morton , "Kirill A. Shutemov" , Zi Yan , Baolin Wang , linux-mm@kvack.org, linux-kernel@vger.kernel.org, opensource.kernel@vivo.com, Rong Qianfeng Subject: Re: [PATCH] mm: Skip the reserved bootmem for compaction Message-ID: References: <20240902122445.11805-1-rongqianfeng@vivo.com> <5fmd2poyeas2pomho2io5zgmqd26vnxd77czmlhqn5tapy4fv4@5tdcqamzgyj5> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: C3B6A1C0020 X-Stat-Signature: 461dmhmmy9rk4ts6rmty555osnrjpnb3 X-Rspam-User: X-HE-Tag: 1725464459-375515 X-HE-Meta: U2FsdGVkX18YX22Vh3N3hVAZCN2ls7L5glGpI/Xodl4ZYhqqXu3sL64G3vKXKrWKj9la8Yk3jWpXQoONj/ZJfOl3QOjQJIS5aWlhz/kFmeBx/RToc958ev4B7ElhCBbOpbjQ/0eMjEmXSsjXrYHKRhBP1Zl8r56j5x2qkfc5b10vRPNCgud6D7OTYyZv6az7OO5dPIRgusGYn3vrZy0Avgq4vc6SM83WK4Yxp/Yw/Gsgng9wTWdaT3ETj0taHjuUQ4k90eCFGyuVV2wdkGbQ9yntGGhFa97ZQQPJBA8RkfRXxHmxU4aDqfS+1dq5dgSfFtmLgOsr4M3lm1+s59Ga8c+wWRYjw53OBrx9yB2bB77l4xgBIedr/sNo5C6CdDnBU5scCgP8tWvQt1zaGRkHy3Zmc3xbE5rRHQ1w17VAneuu76scGsZUoQCUuQsSBC3hZMErCif0jt5ALCbqBmY4PqREO4OxVRuZYMqVp6EgnbXfAoUUSdG2hlEfy9cdHJe10nyNMLcLsKN+QJBFDHQwqMc/MlOJNdNHOw/tLENWw/K3R+lXhl7DRUHZNUDKsaMXpgJBQvWRB+AFph7AP561S5ABbQXOuAXr+rRM+q9IJCd3ZDSioAY5ZDex8o8ggxc8GZmoP3kqW7gB/b6IWVkXqYltEnr6PtMmvW/CR8rIXkY7db2T1K9ImAclMqUuuekLIEG7qyWwb+QsXASBv54axxVxjQe17moeCSMjC/urJp+Tv+rizfkk0m+h2Xqsw7hjTV2fuq5xX0ex4oauZ80OvmMNqc+AK2LNFkQ1ZHlfBho+GjfpR8P0wxDh8DLMI2kLbjGx/CHYD+R+8Vy8bVMERjazlXXUQCkZ2YLvtREDTSQKpNw6PzkXovyCvYN2LwiKhELSnMzfa5tfWDTE7RqvjW90wzeG07LU4zh8AOWiYRpIxuygJKjs3oQOS6dkggzWqO6wrWqBmOYtxOJcLtV Tf51S+cM sNp9S9OU8yPJkDD1/gHmBe6MfEMPxtzuccQumuN/C5ibnEtmmAqr8bqNitiph3eyECzCTpVsYmPav7Y/meKqbzz9qkI4H6AIf9+UAKHJlI71xe1qCkJ782FEl/7vkhxuevy7E5pO6NiYHuINzr6SpBDnMZr1UZ+pcTQJ6MOfdzCjbLmb33yfvf0B9vt3p5d86grcUIpdkt2OJNa3IojRcmGOsSFgA1goQq9ksxjGhh71BF3FuJiHWBeo029ZI6KOA1d/lSdJPgk3M54uAMS4Tt8ZxUIIq6M6hnnNG3XnN5vR0SiDVHQUISxEevfY3rEkWUagd 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 Wed, Sep 04, 2024 at 07:59:37PM +0800, Rong Qianfeng wrote: > Hi Mel, > > 在 2024/9/4 19:13, Mel Gorman 写道: > > On Mon, Sep 02, 2024 at 08:24:43PM +0800, Rong Qianfeng wrote: > > > Reserved pages are basically non-lru pages. This kind of memory can't be > > > used as migration sources and targets, skip it can bring some performance > > > benefits. > > > > > > Because some drivers may also use PG_reserved, we just set PB_migrate_skip > > > for those clustered reserved bootmem during memory initialization. > > > > > > Signed-off-by: Rong Qianfeng > > I'm not convinced the savings due to skipping a few pages during the scan > > would justify the additional code. There would have to be a large number > > of reserved pages scattered throughout the zone to make a difference and > > even that situation would be a big surprise. I'm not even sure this can be > > explicitly tested unless you artifically create reserved pages throughout the > > zone, which would not be convincing, or know if a driver that exhibits such > > behaviour in which case my first question is -- what is that driver doing?!? > > Thanks for taking the time to reply. > > At first I thought that there was not much PageReserved pages, but when I > looked at the memory initialization code, I found that no-map pages were > also marked as PageReserved.  On mobile platforms, there is a lot of no-map > pages (for example, ARM64 MT6991 no-map pages has 1065MB).  These > pages are usually used by various hardware subsystems such as modem.  So > I think it makes sense to skip these pages. > > > //no-map and  reserved memory marked as PageReserved > static void __init memmap_init_reserved_pages(void) > { > ... >     for_each_mem_region(region) { > ... >         if (memblock_is_nomap(region)) >             reserve_bootmem_region(start, end, nid);  //for no-map memory If nomap regions are a problem won't that be simpler to make all pageblocks of a nomap region PB_migrate_skip here and leave other reserved pages alone? > >         memblock_set_node(start, end, &memblock.reserved, nid); >     } > >     for_each_reserved_mem_region(region) { >         if (!memblock_is_reserved_noinit(region)) { > ... >             reserve_bootmem_region(start, end, nid); //for reserved memory >         } >     } > > } > > Best Regards, > Qianfeng -- Sincerely yours, Mike.