From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from shelob.surriel.com (shelob.surriel.com [96.67.55.147]) (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 169ED4A9D62 for ; Wed, 14 Oct 2026 20:54:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=96.67.55.147 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792011277; cv=none; b=k9o9IV2Dvo3JLbkR/LyEyM9XaVsBm70wxx2xww+5nfr7h05ewk+HxROZlFBFk2CQWNgh4dAGI782FHCOQ/OoQY7d5HmNOnPqbOPSNdmyxQmjkJGs053Vw+2+cyfprrtRTcWU4VmKjsO/j2MvChTTMteiVua1BzXReIWGpeOj0/A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792011277; c=relaxed/simple; bh=4KW72QuKC9gmv1jraMYGyizq1JNJIfjBAssCJEpMUQE=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=UhmbyVlh4EeH1CRwuOUWJWN9JOYSIKckMHUCMTnfBX8+ryYAk9R/8x7Wz/sIWly+EG0CdWiXfI9K0bwgoVXq1pM97+3IKPjcnHVVG7c7KQH+mHTxJTPek4LuCfT7LZBOv9OMDxvjt+CeKqmKe0O3W/n/aqzk1AegLo+UyrVMjZY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=surriel.com; spf=pass smtp.mailfrom=surriel.com; dkim=pass (2048-bit key) header.d=surriel.com header.i=@surriel.com header.b=mlsfcTY3; arc=none smtp.client-ip=96.67.55.147 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=surriel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=surriel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=surriel.com header.i=@surriel.com header.b="mlsfcTY3" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=surriel.com ; s=mail; h=MIME-Version:Content-Transfer-Encoding:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID; bh=nDxZe5zkbk1pmGSLhA7tLfIExZwUZ0obZcnML/ZunGs=; b=mlsfcT Y3ePSJP/O8uZJ3sGdAzB8HRGmMsa9DMIwYZe3Wb0uhIyu7BGynAAxMkvzlc8osprofyVObT62geNO cUXorem5pPYeNg9q2h4j1ICTEsVU0njVVYiBiD6zwL2SOfcrLoL6YJKtxaW6Umev9EmqrgyAcXS77 zmOl2Uddms80l5ls6TL6MHAxKEAMCvzQWOWZ9FsRhwXRxfOINABGo2u46O7vhuaz7j5862ZCoKZLR C5sHmwxKC2e8W6Ah6EYE1Ggige664IwgZYqVLZhiqHnRAmZ/kq620sT8nnOrJs8CuBGWX4rptQLLS xI7iTlkELzdyByW9w9WCkXvJh1bw==; Received: from [2601:18c:8100:a0e0:2541:b86e:2586:d219] by shelob.surriel.com with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.99.5) (envelope-from ) id 1xH5z6-00000007lrR-3Dab; Wed, 14 Oct 2026 20:54:00 +0000 Message-ID: <5234543d2c1b44706501d2e079b41e95a6a1d200.camel@surriel.com> Subject: Re: [RFC PATCH 3/5] mm/page_alloc: convert any movable pageblock on a non-movable allocation From: Rik van Riel To: Johannes Weiner Cc: linux-kernel@vger.kernel.org, Andrew Morton , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Zi Yan , Kairui Song , Qi Zheng , Shakeel Butt , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baoquan He , Baolin Wang , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport , linux-mm@kvack.org Date: Wed, 14 Oct 2026 16:53:59 -0400 In-Reply-To: <20261014204836.GI371161@cmpxchg.org> References: <20261007021250.1665929-1-riel@surriel.com> <20261007021250.1665929-4-riel@surriel.com> <20261014204836.GI371161@cmpxchg.org> Autocrypt: addr=riel@surriel.com; prefer-encrypt=mutual; keydata=mQENBFIt3aUBCADCK0LicyCYyMa0E1lodCDUBf6G+6C5UXKG1jEYwQu49cc/gUBTTk33A eo2hjn4JinVaPF3zfZprnKMEGGv4dHvEOCPWiNhlz5RtqH3SKJllq2dpeMS9RqbMvDA36rlJIIo47 Z/nl6IA8MDhSqyqdnTY8z7LnQHqq16jAqwo7Ll9qALXz4yG1ZdSCmo80VPetBZZPw7WMjo+1hByv/ lvdFnLfiQ52tayuuC1r9x2qZ/SYWd2M4p/f5CLmvG9UcnkbYFsKWz8bwOBWKg1PQcaYHLx06sHGdY dIDaeVvkIfMFwAprSo5EFU+aes2VB2ZjugOTbkkW2aPSWTRsBhPHhV6dABEBAAG0HlJpayB2YW4gU mllbCA8cmllbEByZWRoYXQuY29tPokBHwQwAQIACQUCW5LcVgIdIAAKCRDOed6ShMTeg05SB/986o gEgdq4byrtaBQKFg5LWfd8e+h+QzLOg/T8mSS3dJzFXe5JBOfvYg7Bj47xXi9I5sM+I9Lu9+1XVb/ r2rGJrU1DwA09TnmyFtK76bgMF0sBEh1ECILYNQTEIemzNFwOWLZZlEhZFRJsZyX+mtEp/WQIygHV WjwuP69VJw+fPQvLOGn4j8W9QXuvhha7u1QJ7mYx4dLGHrZlHdwDsqpvWsW+3rsIqs1BBe5/Itz9o 6y9gLNtQzwmSDioV8KhF85VmYInslhv5tUtMEppfdTLyX4SUKh8ftNIVmH9mXyRCZclSoa6IMd635 Jq1Pj2/Lp64tOzSvN5Y9zaiCc5FucXtB9SaWsgdmFuIFJpZWwgPHJpZWxAc3VycmllbC5jb20+iQE +BBMBAgAoBQJSLd2lAhsjBQkSzAMABgsJCAcDAgYVCAIJCgsEFgIDAQIeAQIXgAAKCRDOed6ShMTe g4PpB/0ZivKYFt0LaB22ssWUrBoeNWCP1NY/lkq2QbPhR3agLB7ZXI97PF2z/5QD9Fuy/FD/jddPx KRTvFCtHcEzTOcFjBmf52uqgt3U40H9GM++0IM0yHusd9EzlaWsbp09vsAV2DwdqS69x9RPbvE/Ne fO5subhocH76okcF/aQiQ+oj2j6LJZGBJBVigOHg+4zyzdDgKM+jp0bvDI51KQ4XfxV593OhvkS3z 3FPx0CE7l62WhWrieHyBblqvkTYgJ6dq4bsYpqxxGJOkQ47WpEUx6onH+rImWmPJbSYGhwBzTo0Mm G1Nb1qGPG+mTrSmJjDRxrwf1zjmYqQreWVSFEt26tBpSaWsgdmFuIFJpZWwgPHJpZWxAZmIuY29tP okBPgQTAQIAKAUCW5LbiAIbIwUJEswDAAYLCQgHAwIGFQgCCQoLBBYCAwECHgECF4AACgkQznneko TE3oOUEQgAsrGxjTC1bGtZyuvyQPcXclap11Ogib6rQywGYu6/Mnkbd6hbyY3wpdyQii/cas2S44N cQj8HkGv91JLVE24/Wt0gITPCH3rLVJJDGQxprHTVDs1t1RAbsbp0XTksZPCNWDGYIBo2aHDwErhI omYQ0Xluo1WBtH/UmHgirHvclsou1Ks9jyTxiPyUKRfae7GNOFiX99+ZlB27P3t8CjtSO831Ij0Ip QrfooZ21YVlUKw0Wy6Ll8EyefyrEYSh8KTm8dQj4O7xxvdg865TLeLpho5PwDRF+/mR3qi8CdGbkE c4pYZQO8UDXUN4S+pe0aTeTqlYw8rRHWF9TnvtpcNzZw== Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.60.2 (3.60.2-1.fc44) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Wed, 2026-10-14 at 22:48 +0200, Johannes Weiner wrote: > On Tue, Oct 06, 2026 at 10:12:48PM -0400, Rik van Riel wrote: > > try_to_claim_block() converts a movable pageblock for a non-movable > > allocation only when half its pages are free or compatible. > > Otherwise the steal path takes pages without converting, and > > non-movable content sits in a block still typed movable. > >=20 > > Convert a movable block on any non-movable claim, however few of > > its pages are free, so the block's type matches the allocation it > > serves. > >=20 > > When other pages in the block are freed later, they end up on the > > non-movable free lists, directing more non-movable allocations to > > the already non-movable page blocks. > >=20 > > Converting a non-movable pageblock to movable is made stricter: > > a movable claim takes a non-movable block only when every page > > is free or movable. > >=20 > > Blocks straddling a zone edge are never claimed; > > zone_spans_pageblock() tests for a block wholly inside its zone. > >=20 > > Assisted-by: LLM > > Signed-off-by: Rik van Riel >=20 > I like this in theory, but wonder how this behaves in practice. >=20 > The block is claimed, but the movable constituents aren't proactively > kicked out. I have code for that, too, but it seems like it's a lot easier to get things reviewed in small portions. If you want I can resend this as a larger series, with: 1) the pageblock claiming 2) per migrate type free lists 3) evacuation of movable pages from unmovable=C2=A0 pageblocks, when the kernel free lists fall=C2=A0 below a watermark That would be the full extent of the 2MB granularity fragmentation avoidance stuff I have here. Just let me know your preference. --=20 All Rights Reversed.