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 12DF110BA431 for ; Fri, 27 Mar 2026 07:29:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 536426B0005; Fri, 27 Mar 2026 03:29:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 50E4B6B0099; Fri, 27 Mar 2026 03:29:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 44A7E6B009B; Fri, 27 Mar 2026 03:29:30 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 339546B0099 for ; Fri, 27 Mar 2026 03:29:30 -0400 (EDT) Received: from smtpin09.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id DE48F160FDD for ; Fri, 27 Mar 2026 07:29:29 +0000 (UTC) X-FDA: 84591017658.09.E71CC55 Received: from out-179.mta1.migadu.com (out-179.mta1.migadu.com [95.215.58.179]) by imf29.hostedemail.com (Postfix) with ESMTP id 1C52112000C for ; Fri, 27 Mar 2026 07:29:27 +0000 (UTC) Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=ox3nCwo8; spf=pass (imf29.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.179 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Authentication-Results: i=1; imf29.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=ox3nCwo8; spf=pass (imf29.hostedemail.com: domain of lance.yang@linux.dev designates 95.215.58.179 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1774596568; a=rsa-sha256; cv=none; b=IdTWkNjwOvZ01SaSSqcjHFXxkdFasI24zyS7pDj3mz2k2RLcZ7DwCSBD/SVl2A1DaGxkE+ PoZlGFgWUfKfM0wfQKe93UYdQBR4BcVpsDTk8mLp5lcEDsXSrFBx94Q6z2x8cxzWOC85xp mX+zBc6Y3I+6Dzz/+1K0a7EObUCIVBU= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1774596568; 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=8PVUMllx9roLVYGuErAn8ZTvJWl2ucu/IWwrTH7LZxM=; b=4JVuT38iuM+t+Oco42v3PZXaZAaTF6S0KXvfY64Fm46PXFlwK851rHgknuO7+r5k7aw8Iq rs6amUMvbkGdWA02rmKQOex/VOcktwCTlRj6Fr4s2vxt+w8EBS6glTpHJDkhxvlFfiwBjR jSOSu5s32MVtwKTo0o9o6+HTGcpLDMM= 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=1774596565; 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=8PVUMllx9roLVYGuErAn8ZTvJWl2ucu/IWwrTH7LZxM=; b=ox3nCwo83xjPmHsH25jtZvfi47UYkpcpsgdfU0K+K5oldz/OcHPPSHjnn5pFX42Wls5vXc rNFIQR8MoOh0foEg6JFagB5C7tnJiClvkiS15v7LnC6EeNv12LdziqkhNU90QcKELv89uZ YGP/nfRe6E9BvTuukXmXKEdDLOc/mbQ= From: Lance Yang To: ziy@nvidia.com Cc: willy@infradead.org, songliubraving@fb.com, clm@fb.com, dsterba@suse.com, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, shuah@kernel.org, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH v1 02/10] mm/khugepaged: remove READ_ONLY_THP_FOR_FS check Date: Fri, 27 Mar 2026 15:29:17 +0800 Message-Id: <20260327072917.68630-1-lance.yang@linux.dev> In-Reply-To: <20260327014255.2058916-3-ziy@nvidia.com> References: <20260327014255.2058916-3-ziy@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 1C52112000C X-Stat-Signature: pxizwfu6zj3178x86yrwfxky1erb88jd X-Rspam-User: X-HE-Tag: 1774596567-621698 X-HE-Meta: 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Mar 26, 2026 at 09:42:47PM -0400, Zi Yan wrote: >collapse_file() requires FSes supporting large folio with at least >PMD_ORDER, so replace the READ_ONLY_THP_FOR_FS check with that. shmem with >huge option turned on also sets large folio order on mapping, so the check >also applies to shmem. > >While at it, replace VM_BUG_ON with returning failure values. > >Signed-off-by: Zi Yan >--- > mm/khugepaged.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > >diff --git a/mm/khugepaged.c b/mm/khugepaged.c >index d06d84219e1b..45b12ffb1550 100644 >--- a/mm/khugepaged.c >+++ b/mm/khugepaged.c >@@ -1899,8 +1899,11 @@ static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr, > int nr_none = 0; > bool is_shmem = shmem_file(file); > >- VM_BUG_ON(!IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && !is_shmem); >- VM_BUG_ON(start & (HPAGE_PMD_NR - 1)); >+ /* "huge" shmem sets mapping folio order and passes the check below */ >+ if (mapping_max_folio_order(mapping) < PMD_ORDER) >+ return SCAN_FAIL; Yep, for shmem inodes, if the mount has huge= enabled, inode creation marks the mapping are large-folio capable: /* Don't consider 'deny' for emergencies and 'force' for testing */ if (sbinfo->huge) mapping_set_large_folios(inode->i_mapping); LGTM! Reviewed-by: Lance Yang