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 8BB23FB3CE7 for ; Mon, 30 Mar 2026 09:15:59 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B75C96B0092; Mon, 30 Mar 2026 05:15:58 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B4D386B0095; Mon, 30 Mar 2026 05:15:58 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A89D76B0096; Mon, 30 Mar 2026 05:15:58 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id 999CB6B0092 for ; Mon, 30 Mar 2026 05:15:58 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 294308C430 for ; Mon, 30 Mar 2026 09:15:58 +0000 (UTC) X-FDA: 84602172396.06.7411A85 Received: from out-174.mta0.migadu.com (out-174.mta0.migadu.com [91.218.175.174]) by imf12.hostedemail.com (Postfix) with ESMTP id 05D2D40005 for ; Mon, 30 Mar 2026 09:15:55 +0000 (UTC) Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=JlEVi6V9; spf=pass (imf12.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.174 as permitted sender) smtp.mailfrom=lance.yang@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1774862156; 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=LSCJ0gl8vSa6PI9GtiEGiz02O1vonLLeMqbuDT2/pT0=; b=77WBL4IFbdjcgxZ1tb51KqrixOIdfghomjrYyZEM5V4dtj9OKWxyQjfnyte0AuOQtsOSWQ SBwkmMjp8iarijv+84ymkRFHoaUFLzvuIj+icTlSRfmvfPg1XJx1riAWCisQBL94A0leyo XcGAvvJjoUkrShJUwaWxH8l/FGFbFrU= ARC-Authentication-Results: i=1; imf12.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=JlEVi6V9; spf=pass (imf12.hostedemail.com: domain of lance.yang@linux.dev designates 91.218.175.174 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=1774862156; a=rsa-sha256; cv=none; b=edC8MOSk91j8sRHRC8GTv/iDMcDCl/yM0yUspWH5K4u6rW0gIukC9V1BupEl/sb2ZiGUr1 /yeg4tegGJjlpatN6QGRchcvF53DXaMqaMXUkXMVv5KlrVMi1O0yVf78JDqwvmjHut31t0 IrnKzRDOQa4R6Zibwnei9xzQAJ/lbj0= 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=1774862153; 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=LSCJ0gl8vSa6PI9GtiEGiz02O1vonLLeMqbuDT2/pT0=; b=JlEVi6V9Dvb4mKdK823yLSF2UnR/iHJ0WcmyNTy0zY2Vi0Iw/QhfgPYo49r/guOUtqs07o 2wEfzceNfeC0ZghYSXatqvUiQtxgYTkFjR+fQdkCMeaKASv6tP9fKcmehrrBDbe60u65DD rd2PAY99ZUhzsT3Xo99AG1Jk0KJicfE= 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 06/10] mm/huge_memory: remove folio split check for READ_ONLY_THP_FOR_FS Date: Mon, 30 Mar 2026 17:15:36 +0800 Message-Id: <20260330091536.20015-1-lance.yang@linux.dev> In-Reply-To: <20260327014255.2058916-7-ziy@nvidia.com> References: <20260327014255.2058916-7-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-Queue-Id: 05D2D40005 X-Stat-Signature: 8jbiyyci37ph85q5s58xtk6d6b9z85oz X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1774862155-456862 X-HE-Meta: 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 Kg5vBWNZ BkpGaBmico2Po2+5+9skvz/dfrMWztJYXdSNFulWvQ+Rdct3ZLha9nViF91/COz9jonYTXzN1x+00HfcMGq2s1ysbrdPHEt8kVpACPGkY8yhLzw+1096T6eQ2cmbFr1UIYWZzkoPL3wQKe0J25e9odMWFJJlochSTyugTkBEArq2EQJgzq1LEWk6wpEFXi85QCMRivHqPUd2Dkd+cVzmyXqi9vV3vEmfxiC+uIEysQvdqEBWuacHkmWTVQfTFo20a7sMQZaWtq/QjilBc5o5q8ZR1+A== 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 09:42:51PM -0400, Zi Yan wrote: >Without READ_ONLY_THP_FOR_FS, large file-backed folios cannot be created by >a FS without large folio support. The check is no longer needed. > >Signed-off-by: Zi Yan >--- > mm/huge_memory.c | 22 ---------------------- > 1 file changed, 22 deletions(-) > >diff --git a/mm/huge_memory.c b/mm/huge_memory.c >index 1da1467328a3..30eddcbf86f1 100644 >--- a/mm/huge_memory.c >+++ b/mm/huge_memory.c >@@ -3732,28 +3732,6 @@ int folio_check_splittable(struct folio *folio, unsigned int new_order, > /* order-1 is not supported for anonymous THP. */ > if (new_order == 1) > return -EINVAL; While you're at it, could we also collapse this block above into a single condition: /* order-1 is not supported for anonymous THP. */ if (folio_test_anon(folio) && new_order == 1) return -EINVAL; Just saying. LGTM. Reviewed-by: Lance Yang >- } else if (split_type == SPLIT_TYPE_NON_UNIFORM || new_order) { >- if (IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && >- !mapping_large_folio_support(folio->mapping)) { >- /* >- * We can always split a folio down to a single page >- * (new_order == 0) uniformly. >- * >- * For any other scenario >- * a) uniform split targeting a large folio >- * (new_order > 0) >- * b) any non-uniform split >- * we must confirm that the file system supports large >- * folios. >- * >- * Note that we might still have THPs in such >- * mappings, which is created from khugepaged when >- * CONFIG_READ_ONLY_THP_FOR_FS is enabled. But in that >- * case, the mapping does not actually support large >- * folios properly. >- */ >- return -EINVAL; >- } > } > > /*