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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C97EF1098797 for ; Fri, 20 Mar 2026 15:06:11 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 14DFF6B00D4; Fri, 20 Mar 2026 11:06:11 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 0FEB36B00D8; Fri, 20 Mar 2026 11:06:11 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F2FE96B00DC; Fri, 20 Mar 2026 11:06:10 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id DD2E96B00D4 for ; Fri, 20 Mar 2026 11:06:10 -0400 (EDT) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 86C24B7B27 for ; Fri, 20 Mar 2026 15:06:10 +0000 (UTC) X-FDA: 84566766900.25.295F55A Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf23.hostedemail.com (Postfix) with ESMTP id 722D7140016 for ; Fri, 20 Mar 2026 15:06:08 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="mvpIdq/9"; spf=pass (imf23.hostedemail.com: domain of kas@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=kas@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1774019168; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ysbNj8lFw8IfnnCT5+m33HcLxVUrxAw+EMUT91iRs7Q=; b=S0X3Dl/Yl9v2lYuyLa3RmOjNtWBPX/0i4tkdqw3Iul0KCFQ9Kf781/Cs9Rt2jp3aw72u2o u8EPa1hoLYMBb6rm+YuSfgiBGVFoI7KuoPEa3YgPeUWiDg8TlsdZ24GsXRgkkbP2Vf5OgG xLWCpvd+qPnJaiskwPj9Smr4zKcKNCU= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="mvpIdq/9"; spf=pass (imf23.hostedemail.com: domain of kas@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=kas@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1774019168; a=rsa-sha256; cv=none; b=hRGV9XOC/38wF5i+nWNxQvnKsTMdBbQW38hvnGUNYUdCEUFllI9l1WADYE4Oos+pBOizQN nvaFPHh/Y+rgg+ThEhGVi1X7UddN+jETdMiufD63m1szLY9hLuYZo49U60/oG6Y8TcrUp+ /IciZBJrsntsgYO6f3NY46AHSt+zCg4= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id E65C56185E; Fri, 20 Mar 2026 15:06:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AE725C4AF09; Fri, 20 Mar 2026 15:06:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774019167; bh=a5V6KVj/p5ln89F2tRrdVmVw8oemreTmSe3BZkx0iwI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mvpIdq/9d72DivkgvVtymQHXH7jVuQuYKi3+LQHQ0f58tkUJ728fEqgRkKtSJZoaN pbFtnOrAxJ13dAXGYHacB7GiWq/px7693hwN8squYYUeIxksnEMb2cQRWnyaBSSDAs N3nR1vFYOOw53CMX9KGCjVkVS7tmkdKy/w1SjtNibjIDdexgi4vYDL8QvZT+6WWD7Y nPIxAOAO/qfHwUNAe16FCr7yOJHR4cgua67djnjnxCltxrKPlawhJIrcceYIc6/NMK 69I+FE4vf7u/FEX4iR3I6J/6gTnnfOkzzEw1+ndDtVN8galvJvxQkL4Z3vdTlfZV3X g8h9ZDpMBnBAw== Received: from phl-compute-04.internal (phl-compute-04.internal [10.202.2.44]) by mailfauth.phl.internal (Postfix) with ESMTP id AC0A5F4008E; Fri, 20 Mar 2026 11:06:05 -0400 (EDT) Received: from phl-frontend-04 ([10.202.2.163]) by phl-compute-04.internal (MEProxy); Fri, 20 Mar 2026 11:06:05 -0400 X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeefgedrtddtgdefuddtvdefucetufdoteggodetrf dotffvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfurfetoffkrfgpnffqhgenuceu rghilhhouhhtmecufedttdenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujf gurhepfffhvfevuffkfhggtggujgesthdtredttddtvdenucfhrhhomhepmfhirhihlhcu ufhhuhhtshgvmhgruhcuoehkrghssehkvghrnhgvlhdrohhrgheqnecuggftrfgrthhtvg hrnhepueeijeeiffekheeffffftdekleefleehhfefhfduheejhedvffeluedvudefgfek necuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehmrghilhhfrhhomhepkhhirh hilhhlodhmvghsmhhtphgruhhthhhpvghrshhonhgrlhhithihqdduieduudeivdeiheeh qddvkeeggeegjedvkedqkhgrsheppehkvghrnhgvlhdrohhrghesshhhuhhtvghmohhvrd hnrghmvgdpnhgspghrtghpthhtohepjedtpdhmohguvgepshhmthhpohhuthdprhgtphht thhopehushgrmhgrrdgrrhhifheslhhinhhugidruggvvhdprhgtphhtthhopegrkhhpmh eslhhinhhugidqfhhouhhnuggrthhiohhnrdhorhhgpdhrtghpthhtohepuggrvhhiuges khgvrhhnvghlrdhorhhgpdhrtghpthhtohepfihilhhlhiesihhnfhhrrgguvggrugdroh hrghdprhgtphhtthhopehrhigrnhdrrhhosggvrhhtshesrghrmhdrtghomhdprhgtphht thhopehlihhnuhigqdhmmheskhhvrggtkhdrohhrghdprhgtphhtthhopehrsehhvghvrd gttgdprhgtphhtthhopehjrggtkhesshhushgvrdgtiidprhgtphhtthhopegrjhgusehl ihhnuhigrdhisghmrdgtohhm X-ME-Proxy: Feedback-ID: i10464835:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Fri, 20 Mar 2026 11:06:04 -0400 (EDT) Date: Fri, 20 Mar 2026 15:06:03 +0000 From: Kiryl Shutsemau To: Usama Arif Cc: Andrew Morton , david@kernel.org, willy@infradead.org, ryan.roberts@arm.com, linux-mm@kvack.org, r@hev.cc, jack@suse.cz, ajd@linux.ibm.com, apopple@nvidia.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, brauner@kernel.org, catalin.marinas@arm.com, dev.jain@arm.com, kees@kernel.org, kevin.brodsky@arm.com, lance.yang@linux.dev, Liam.Howlett@oracle.com, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, lorenzo.stoakes@oracle.com, mhocko@suse.com, npache@redhat.com, pasha.tatashin@soleen.com, rmclure@linux.ibm.com, rppt@kernel.org, surenb@google.com, vbabka@kernel.org, Al Viro , ziy@nvidia.com, hannes@cmpxchg.org, shakeel.butt@linux.dev, kernel-team@meta.com Subject: Re: [PATCH v2 4/4] mm: align file-backed mmap to max folio order in thp_get_unmapped_area Message-ID: References: <20260320140315.979307-1-usama.arif@linux.dev> <20260320140315.979307-5-usama.arif@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260320140315.979307-5-usama.arif@linux.dev> X-Rspamd-Queue-Id: 722D7140016 X-Stat-Signature: 4ujz1ddmwmkrqroj76mnzoa6tnzi8ju7 X-Rspam-User: X-Rspamd-Server: rspam05 X-HE-Tag: 1774019168-299585 X-HE-Meta: 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 2QVGik6k aE/rshLu92r2rm9bKNkPw5GQ6Ld9PNkSCp5fS9tgl2jkeuPsH1yudCsvfxcEkjVoy8SqT3Mvqqv1KKuNNMEoVpUf8Mldq8uQRpZ6IO64ZtQBaAVzJE+le8Mcfaj8Wcg4MD4pGpFSOknqOVWlxRaa1WYDL7bh7yC0nN6i94E9oKFaQQC83fjHqCbRu86Di6OVjgmVWQsj7n6ZGqWzejfUgKwndH7uL0X7a62sUenykIRoSrrsClhhgG1o6U3eyWF6lENip9PFqz1+KYs38+4V7Tpz6l7iWJc7b4DPctvky2K+bskas3mCcNeQPN/VsO8soGFvyNZzqrqNxsNc= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Mar 20, 2026 at 06:58:54AM -0700, Usama Arif wrote: > thp_get_unmapped_area() is the get_unmapped_area callback for > filesystems like ext4, xfs, and btrfs. It attempts to align the virtual > address for PMD_SIZE THP mappings, but on arm64 with 64K base pages > PMD_SIZE is 512M, which is too large for typical shared library mappings, > so the alignment always fails and falls back to PAGE_SIZE. > > This means shared libraries loaded by ld.so via mmap() get 64K-aligned > virtual addresses, preventing contpte mapping even when 2M folios are > allocated with properly aligned file offsets and physical addresses. > > Add a fallback in thp_get_unmapped_area_vmflags() that uses the > filesystem's mapping_max_folio_size() to determine alignment, capped to > the mapping length via rounddown_pow_of_two(len). This aligns mappings > to the largest folio the page cache will actually allocate, without > over-aligning small mappings. > > The fallback is naturally a no-op for filesystems that don't support > large folios and skips the retry when the alignment would equal PMD_SIZE > (already attempted above). > > Signed-off-by: Usama Arif > --- > mm/huge_memory.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 8e2746ea74adf..4005084c9c65b 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -1242,6 +1242,20 @@ unsigned long thp_get_unmapped_area_vmflags(struct file *filp, unsigned long add > if (ret) > return ret; > > + if (filp && filp->f_mapping) { > + unsigned long max_folio_size = > + mapping_max_folio_size(filp->f_mapping); > + unsigned long size = rounddown_pow_of_two(len); > + > + size = min(size, max_folio_size); > + if (size > PAGE_SIZE && size != PMD_SIZE) { > + ret = __thp_get_unmapped_area(filp, addr, len, off, > + flags, size, vm_flags); Have you considered to integrate inside __thp_get_unmapped_area? Like, start with PMD_SIZE alignment, then lower to mapping_max_folio_size if needed and then lower further based on mapping size. -- Kiryl Shutsemau / Kirill A. Shutemov