From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) (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 1036F37B003 for ; Thu, 2 Apr 2026 18:14:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775153652; cv=none; b=qSJeHRwqAPUMReIuR5GwXeJFPxOzMbzmMOHu675QlwKd1G7/6cPLJaRk0hK42JZAoTYYH7HrqAsaRqunQ6mtHHNplEFoRjNiXn/SXhbXqmVsmbm+R+ck1HlMUQmDKreMGdbDfzGrGiWusXiw+fu/87+TcTUSGNJe4jDdQJ6Zohc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775153652; c=relaxed/simple; bh=OhZbU4NVFupE4pyVzCcACZj5uc3jtjdhtQ5T10gNhGI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=NaeItrmLZ2Ui/IyH7JjHycijUwazidid8lg8+zf0DvQ9hTtq+i+gO0/XFCHbWAuFibgQXK5WqE++srVAsb+bqndGOr57M9MWa4MBcN9vpOTAi9RH5M60kCGZJxIVAQNemPOwbuhXjrKdIeOPtfzpn+NB+/+eLgB8K/c7/GQZrII= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=GCgY7W2u; arc=none smtp.client-ip=91.218.175.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="GCgY7W2u" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1775153646; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xkczfxtSF84VSlTks10/GwIlblAMIDiieRoVjs+yTko=; b=GCgY7W2uOZ9JOJ9TKL9rwScooWJa3NSfsWsGckrshtUKYLwLenqw8/WjLx0Z4uA+sAWq/i MP9pHdN5k++FTE7QpoVImIQJ6P5w7BhPS+mm4Ls/yGqPdljUkJoVqO+6UMRhlpVlz5ICYl 7egdHS89vNwD+WdCQpSsbvwFDNYj6ok= From: Usama Arif To: Andrew Morton , david@kernel.org, willy@infradead.org, ryan.roberts@arm.com, linux-mm@kvack.org Cc: 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 , 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 , wilts.infradead.org, linux-fsdevel@vger.kernel.l@kernel.org, ziy@nvidia.com, hannes@cmpxchg.org, kas@kernel.org, shakeel.butt@linux.dev, leitao@debian.org, kernel-team@meta.com, Usama Arif Subject: [PATCH v3 4/4] mm: align file-backed mmap to exec folio order in thp_get_unmapped_area Date: Thu, 2 Apr 2026 11:08:25 -0700 Message-ID: <20260402181326.3107102-5-usama.arif@linux.dev> In-Reply-To: <20260402181326.3107102-1-usama.arif@linux.dev> References: <20260402181326.3107102-1-usama.arif@linux.dev> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT 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 large folios are allocated with properly aligned file offsets and physical addresses. Add a fallback in thp_get_unmapped_area_vmflags() that uses exec_folio_order() to determine alignment, matching the readahead allocation strategy. This aligns mappings to the hardware TLB coalescing size (e.g. 2M for contpte on arm64 64K pages, 64K for contpte/HPA on arm64 4K/16K pages), capped to the mapping length via rounddown_pow_of_two(len). The fallback is naturally a no-op on architectures where exec_folio_order() returns 0, and skips the retry when the alignment would equal PMD_SIZE (already attempted above) incase another architecture changes exec_folio_order() in the future. Signed-off-by: Usama Arif --- mm/huge_memory.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index b2a6060b3c20..ad97ac8406dc 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1218,6 +1218,19 @@ unsigned long thp_get_unmapped_area_vmflags(struct file *filp, unsigned long add if (ret) return ret; + if (filp && exec_folio_order()) { + unsigned long exec_folio_size = PAGE_SIZE << exec_folio_order(); + unsigned long size = rounddown_pow_of_two(len); + + size = min(size, exec_folio_size); + if (size > PAGE_SIZE && size != PMD_SIZE) { + ret = __thp_get_unmapped_area(filp, addr, len, off, + flags, size, vm_flags); + if (ret) + return ret; + } + } + return mm_get_unmapped_area_vmflags(filp, addr, len, pgoff, flags, vm_flags); } -- 2.52.0