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 0EBC1C982FA for ; Wed, 23 Sep 2026 01:38:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 02B0F6B008C; Tue, 22 Sep 2026 21:38:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F1EA26B0092; Tue, 22 Sep 2026 21:38:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E0CF56B0093; Tue, 22 Sep 2026 21:38:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id B6E006B008C for ; Tue, 22 Sep 2026 21:38:12 -0400 (EDT) Received: from smtpin01.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 46445A06A7 for ; Wed, 23 Sep 2026 01:38:12 +0000 (UTC) X-FDA: 85243316424.01.9D68303 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf24.hostedemail.com (Postfix) with ESMTP id 03964180009 for ; Wed, 23 Sep 2026 01:38:04 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Iw0RKiC3; spf=pass (imf24.hostedemail.com: domain of luizcap@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=luizcap@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1790127485; 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=PxGCM8xxwnmehx2AfVy1IEcUOYJtD/f1L22IPBat84s=; b=pkAXDpDUjZI7LpoZiLunwsiD+8PvQc40i2WOzjf/SKVQ6TH7PnZ6wjQdxhWQPiVPlISs52 qAwYLmAZKn11VFenyCGIniNREbVdI1sgqaiSDVYDfvyx/xxoEwc+PlPfyk+Z0NtorKQ8TJ Odokdn4mfeXnTSmbid4SyKTG4BgjKJc= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=Iw0RKiC3; spf=pass (imf24.hostedemail.com: domain of luizcap@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=luizcap@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1790127485; b=cxB13VuvXaTXJ8l6Grz73rulXkPigaFQ/OTovh0Ez2ELOLYaHAMQxKVkAeKs9wllMmYDAH EnCdZHNz+zbvlp23rXtNH8isRKpBHfTjMRJN3PajIKzbZGpi4aVxYKEU7Zd7XoErQlfJAk Ep0SrRHzp5zBk/F+PQHaBXTnwGhyZBQ= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1790127484; h=from:from: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; bh=PxGCM8xxwnmehx2AfVy1IEcUOYJtD/f1L22IPBat84s=; b=Iw0RKiC3/oZ4TY/KeWoXVfpKn+F9K7jT+japsbOf5Ru7OLHJddI/crxlmktQ400cgnDydn oy+F93MfD7H/+LYminJKb1ZcCpEvFwd7zQvha0t8AkKbMQrQgNv7/RwcDDvcG/Inl/hbNh nHlQ12NCYH8rm59guXb+XZN14XbeiOM= Received: from mail-qt1-f199.google.com (mail-qt1-f199.google.com [209.85.160.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-531-8mANNKkTNHalIvsP-m0NUg-1; Tue, 22 Sep 2026 21:37:56 -0400 X-MC-Unique: 8mANNKkTNHalIvsP-m0NUg-1 X-Mimecast-MFC-AGG-ID: 8mANNKkTNHalIvsP-m0NUg_1790127476 Received: by mail-qt1-f199.google.com with SMTP id d75a77b69052e-5328cdb38bcso9244761cf.3 for ; Tue, 22 Sep 2026 18:37:56 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790127476; x=1790732276; h=content-transfer-encoding:content-type:in-reply-to:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=PxGCM8xxwnmehx2AfVy1IEcUOYJtD/f1L22IPBat84s=; b=Bihfz8LVvRijfwrZW5CHhRPQBoYy9VT0sOXWXg9I+l57bzEMtDJQCXMvz5/Dd3nliD oWwawBV3BZ8GWYnhavo4/viQ0Qmz6QZW2M7IHs5ZnEqw2jXwFSYo/xnDdvy687jP2eEb ZQKZICLrMLWM7e9TKSFhLIhTjQ9UwRYkrUi9bfDmtZiZ4coxrxOFzLIog+tzaxbot1zu 0KJ1r2AGVqFSE6s2pTEUhZGXjQyBHFZYLKQ4NiAw0lL0hOYEXS3Hm5rD1MyFi7BEMrwc p3+g2Cd5V6IA1RCttcCJRiRFltmXwUMho0It5oRlkbgKeAr2RcoNAhiJJF1FlBbhrcNo GwNQ== X-Forwarded-Encrypted: i=1; AKwUvBwIVq3/vVZDZW6qjx5WiLrk9AWnBFzyAVMMbaz51A4+Z2tMoVifmChxt4E4tHjnuWgRu5MWq4MZDQ==@kvack.org X-Gm-Message-State: AFuF++nvfnJX3BW5TJaqKY2s0vXl/eIi3/Qaf0C52NJEbLg36N0BtqPC f9CO01HEmBH9UB5wYrBz5UbjjwsipZi3tGEY8nR1UDosLDYLYZmOlZYhoSqRRWLlbZb8I5HbQ0g MN/6aiTENx8YFLNfvxB3emdJPP6ze3XMX3ERNnv6rz4GZIe8gGUQ3 X-Gm-Gg: AYBFou0W/m710GRlDatYA4/wff5W+lzpxmGcP1V9s/yu0MEwCLKgoSTCoJnqUjfbmwx UhSGFvZhPIfaNWl8brELHc+w7G+fDqM/ait3yFJfjYEVk2pcw7/BuOHBnCytjw4sh7ktizCc8dV GhkQtP+QBBnBCNSp+jr36wrALKQd19+eU3LwhCSeLz828sTw+oItvqOBKhdRd3WXnC/0iVhdl9H 98hve2AIZb7ek3TnJ17kxRnVpurOKYItQqbVeiFkAFsW70UrntiJdhc7TPGSYyy3SXyMhclHveW 0CA297Jsj2k5KylPkVAE0de3FUm42/rr/ZHZn8FpU7LJh0Z3iYJOeLWuzH2WBSezAIDmORdq81v lQSg= X-Received: by 2002:a05:622a:d14:b0:532:f0a2:ee3 with SMTP id d75a77b69052e-532f0a212femr1998421cf.68.1790127476102; Tue, 22 Sep 2026 18:37:56 -0700 (PDT) X-Received: by 2002:a05:622a:d14:b0:532:f0a2:ee3 with SMTP id d75a77b69052e-532f0a212femr1997961cf.68.1790127475647; Tue, 22 Sep 2026 18:37:55 -0700 (PDT) Received: from [192.168.2.110] ([142.172.30.162]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-532eb399581sm9358311cf.28.2026.09.22.18.37.53 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 22 Sep 2026 18:37:55 -0700 (PDT) Message-ID: <3d914185-ac87-4fc7-ab21-de184bfd4e57@redhat.com> Date: Tue, 22 Sep 2026 21:37:53 -0400 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v8 07/14] mm: shmem: allow THP support determination at folio allocation time To: Zi Yan , linux-kernel@vger.kernel.org, linux-mm@kvack.org, david@kernel.org, baolin.wang@linux.alibaba.com, lance.yang@linux.dev Cc: corbet@lwn.net, tsbogend@alpha.franken.de, maddy@linux.ibm.com, mpe@ellerman.id.au, agordeev@linux.ibm.com, gerald.schaefer@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, x86@kernel.org, tglx@kernel.org, mingo@redhat.com, bp@alien8.de, hughd@google.com, dave.hansen@linux.intel.com, djbw@kernel.org, vishal.l.verma@intel.com, dave.jiang@intel.com, akpm@linux-foundation.org, yintirui@huawei.com, dev.jain@arm.com, usama.arif@linux.dev References: From: Luiz Capitulino In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: cZ8EqXdZxHKj5M8494jea6SHEN0nzcW_IdH0XjBIbkM_1790127476 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 03964180009 X-Stat-Signature: sk97xiz3nbxs1hphin16ortxjwrntygq X-Rspam-User: X-HE-Tag: 1790127484-912341 X-HE-Meta: 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 b909rqGM f0c8E5ZYDaXEaYnDC8eWLuvBPdP8Gcl3cDWG6Mm3ClbHNtMeX883Xe2terLvVcVbqbsB2Ci05HDgy220Y8bkqBS43PF3YvhxWC+PQL6UgAqKwzZwSepxwNcMNYcU3dTG8XRn3b+jkoNuuWTG7MxBHBlyXef5hY54BiRj15aWf8+ZrMKYMrHsADHSY3iToWd3PD3fNCTGziPe5XGydMxT9lZbO0+YJH2rlBbVTh8UO0RU1VQ3ybUfNaVJ2nnCgyvJf7onyA9kVSIzCXNeHK5IDtPepeBoc58xBygtVIcSH9wgUkSvyRKfTzf6fCRC1kjr3BTIEbk+F6jGE7ag3/5mC93sMqvtCcgMB3+GvQXO0BQtZmd7BhwxG/oEYGkGltf5iO7Y6N2XieRJep9vtDh2+qt+vVt48QHyZUvXP Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 9/21/26 10:20 PM, Zi Yan wrote: > On Thu Sep 17, 2026 at 9:45 PM EDT, Luiz Capitulino wrote: >> In order to enable THP support in shmem today, besides the user >> configuration required, the CPU must support PMD-sized pages. This >> is the case because of the following has_transparent_hugepage() >> usage: >> >> - shmem_parse_one() and shmem_parse_huge(): Check if THP is built-in and >> if the CPU supports PMD-sized pages >> >> - shmem_init(): Since the CONFIG_TRANSPARENT_HUGEPAGE guard is outside >> the code block calling has_transparent_hugepage(), the >> has_transparent_hugepage() call is exclusively checking if the CPU >> supports PMD-sized pages >> >> While it's necessary to check if CONFIG_TRANSPARENT_HUGEPAGE is enabled >> in all cases, shmem can determine THP size support at folio allocation >> time. Therefore, drop the has_transparent_hugepage() usage listed above >> while keeping the CONFIG_TRANSPARENT_HUGEPAGE checks. >> >> Additionally, we need to check if PMD size order is supported in >> shmem_getattr(). Use pgtable_has_pmd_leaves() for that. >> >> Reviewed-by: Baolin Wang >> Signed-off-by: Luiz Capitulino >> --- >> mm/shmem.c | 9 +++++---- >> 1 file changed, 5 insertions(+), 4 deletions(-) >> >> diff --git a/mm/shmem.c b/mm/shmem.c >> index 776dff8a848e..930657d05375 100644 >> --- a/mm/shmem.c >> +++ b/mm/shmem.c >> @@ -690,7 +690,7 @@ static int shmem_parse_huge(const char *str) >> else >> return -EINVAL; >> >> - if (!has_transparent_hugepage() && >> + if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && >> huge != SHMEM_HUGE_NEVER && huge != SHMEM_HUGE_DENY) >> return -EINVAL; > > This can be deleted, since shmem_parse_huge() is guarded by > CONFIG_TRANSPARENT_HUGEPAGE and after the change the if is always false > under that guard. > > Otherwise, LGTM. With the above code deleted, feel free to add > > Reviewed-by: Zi Yan OK, here's the diff: diff --git a/mm/shmem.c b/mm/shmem.c index c00bc1829fc9..d12995d41846 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -690,10 +690,6 @@ static int shmem_parse_huge(const char *str) else return -EINVAL; - if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && - huge != SHMEM_HUGE_NEVER && huge != SHMEM_HUGE_DENY) - return -EINVAL; - /* Do not override huge allocation policy with non-PMD sized mTHP */ if (huge == SHMEM_HUGE_FORCE && huge_shmem_orders_inherit != BIT(HPAGE_PMD_ORDER))