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 2CA2625B084 for ; Tue, 28 Jul 2026 00:39:05 +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=1785199148; cv=none; b=IKLQjLbtIOMMHQzbpfvoUqDbVw042AIHo3lalLMXk8YEU23ddgsHj56R3TV3gCmME8crpEzxIps6hzY+eeorVloCReZ60gqtQDICoeBCxdgy8dO27vFAEsw1eCT38VL1AedzksTm9dj6PNU6bk7ey5GVnOQx0yPsN/owiiwiyW8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785199148; c=relaxed/simple; bh=9hkekweVDgigm4cPKAiKfOzXU7bCJAvocV05G6iZWjw=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=FGtX+nTk9iv4CO9kvqvoRcV+0K3KVyzcqZLLkUofInsezpWG9YlcxPWGOAKF4AbSEfmkFOiMhptLh9xNnTuSoMTIZ/lOdwQyXdh90RVnNAUChEpExFWewW+oH8f0DB6ZEG7hdW5bqod34kiQsfWBZ/byuofAZ33dAECz5yXzYH8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none 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=KThfH92v; arc=none smtp.client-ip=96.67.55.147 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none 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="KThfH92v" 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:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=9hkekweVDgigm4cPKAiKfOzXU7bCJAvocV05G6iZWjw=; b=KThfH92vzkutKeI61n25jlmzpc yVeuXMICRGx406TBBKU0HhVx6n7Y/gaX79a/xpXdizggnlI3DFB9Hx1Iij+gPnDR+gVFqNCvavXDm gLelQKcRX+ll6F8LKbjL0AKpWnxvbGbHZchPzmV4HXXcktUIGWbkplMOKm6sJ6GFsAX7j4pxCVZ1A i4Y7AXwQ/d64Cg5egQ2PXcDCIqOWVwwHrwgLvWLKKbDuvhaKBQfCtP8Y3vTuzhYcdjbcEWyzIVBBu ZGyDEe9x9Ht6L5gCHc1k2SOYhyHGwTiFsRlvbwgNq0+AkJqmolwhEH5+qCHtBKzUGrlSpW9Wd2xwM uonBAsAA==; Received: from fangorn.home.surriel.com ([10.0.13.7]) by shelob.surriel.com with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.97.1) (envelope-from ) id 1woVot-000000002nW-41zO; Mon, 27 Jul 2026 20:37:19 -0400 Message-ID: Subject: Re: [PATCH RFC v4 11/12] mm/gup: batch contiguous PTE-mapped large folios in follow_page_mask() From: Rik van Riel To: "David Hildenbrand (Arm)" , Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-team@meta.com, Dave Hansen , Peter Zijlstra , Suren Baghdasaryan , Lorenzo Stoakes , Vlastimil Babka , "Liam R. Howlett" , Mike Rapoport , Michal Hocko , Jason Gunthorpe , John Hubbard , Peter Xu , Matthew Wilcox , Usama Arif Date: Mon, 27 Jul 2026 20:37:19 -0400 In-Reply-To: <5490f8b1-d611-4e4d-bd8b-19c0e05698a3@kernel.org> References: <20260724222934.1463812-1-riel@surriel.com> <20260724222934.1463812-12-riel@surriel.com> <5490f8b1-d611-4e4d-bd8b-19c0e05698a3@kernel.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 3.56.2 (3.56.2-2.fc42) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Mon, 2026-07-27 at 15:54 +0200, David Hildenbrand (Arm) wrote: > On 7/25/26 00:29, Rik van Riel wrote: > >=20 > > =C2=A0 gup_test -L -m 256 -n 65536 -r 16 -t > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 befor= e=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 after > > =C2=A0 64 kB mTHP=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0 3140 us=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 412 us=C2=A0=C2=A0 (7.6x= ) > > =C2=A0 2 MB THP (control)=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 78 us=C2=A0=C2= =A0=C2=A0=C2=A0=C2=A0=C2=A0 76 us > > =C2=A0 4 kB base (control)=C2=A0=C2=A0 3010 us=C2=A0=C2=A0=C2=A0=C2=A0 = 3042 us > >=20 > > The PMD-mapped 2 MB THP already returns the whole mapping in one > > step, so > > it stays fast and unchanged. The 4 kB baseline shows the per-page > > walk cost > > that the 64 kB case paid before this change; only the PTE-mapped > > large > > folio case improves. > >=20 > > Assisted-by: Claude:claude-opus-4.8 > > Signed-off-by: Rik van Riel >=20 > Why is this patch part of this patch set? >=20 > This makes perfect sense independently, no? I'm happy to drop this for now. I think it would fit in better with another optimization to only take one refcount per continuously mapped extent of pages from the same folio. I can't really untangle it because it modifies some of the same code as other patches in the series, but I'm happy to save it for a follow-up. --=20 All Rights Reversed.