From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-132.freemail.mail.aliyun.com (out30-132.freemail.mail.aliyun.com [115.124.30.132]) (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 2917623D7D4; Mon, 9 Mar 2026 03:03:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.132 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773025436; cv=none; b=OWK5FLQ2BCokpn7uUs7/34IOU+wPCmpZihjRjTRxAtU7HiE1aEbrfE2NmteZBh9Z2aC02hcOBOJ5hOmVP1jSFPM6EvNqcrRe5uV0CTMd8B+7HRcskMUkJpYskP3Qf8H7FSYgUI51HPcJ4AMfDF0/DzwOhojbaeXwUYlPBASq1Ok= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773025436; c=relaxed/simple; bh=AL4Gafn6UmGjBWuNtjw40LkSc/3hSc3lyJ0eldxActo=; h=Message-ID:Date:MIME-Version:From:Subject:To:Cc:References: In-Reply-To:Content-Type; b=lnZ2UaDGPtmDHKPKDs4qdpUAYYFCzdj48ExBuWTlvsFAMLA/zPxYk0T/hbNDiuluJoHZAavQgb1uMeKyM8ju9UD3uQ3ZZOE9t3B/7siAdkEeVziiHWF2tjYDzpdrTXtDCFFy8/9UiZ2RcTJY4o8yIpWxKLUJFOPo7/6txvGvruA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=VamfZ/M6; arc=none smtp.client-ip=115.124.30.132 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="VamfZ/M6" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1773025425; h=Message-ID:Date:MIME-Version:From:Subject:To:Content-Type; bh=wXruS7sYNNs5AqEinrpNUsbJNbVP+SAbifLRwxw2WSM=; b=VamfZ/M6/RsjdsfogEwuD4Un596WMDrWLF9/Q/QHVdYPOjvSWEfMUqf3jOukrdlm+csmK/Cae0KHG9v6KwOlkrock5v4R5GRsghUnW+iXxG8ayHF4DpVGvmQdGAAFYxoXXXggDNe8NGjEGgUC2Gb7fpmKMewHCqY7NFgh5D1/0o= Received: from 30.170.14.2(mailfrom:hsiangkao@linux.alibaba.com fp:SMTPD_---0X-TT8RS_1773025423 cluster:ay36) by smtp.aliyun-inc.com; Mon, 09 Mar 2026 11:03:44 +0800 Message-ID: <02925ac8-64a6-4cd6-bbd4-c37d838f862a@linux.alibaba.com> Date: Mon, 9 Mar 2026 11:03:43 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Gao Xiang Subject: Re: [PATCH] erofs: introduce nolargefolio mount option To: Chao Yu , xiang@kernel.org Cc: linux-erofs@lists.ozlabs.org, linux-kernel@vger.kernel.org, Yue Hu , Jeffle Xu , Sandeep Dhavale , Chunhai Guo , Hongbo Li , linux-erofs mailing list , Matthew Wilcox , Jan Kara , "linux-fsdevel@vger.kernel.org" References: <20260309023053.1685839-1-chao@kernel.org> In-Reply-To: <20260309023053.1685839-1-chao@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Chao, (+cc -fsdevel, willy, Jan kara) On 2026/3/9 10:30, Chao Yu wrote: > This patch introduces a new mount option 'nolargefolio' for EROFS. > When this option is specified, large folio will be disabled by > default for all inodes, this option can be used for environments > where large folio resources are limited, it's necessary to only > let specified user to allocate large folios on demand. For this kind of options, I think more real backgrounds about avoiding high-order allocations are needed in the commit message (at least for later reference) also like what I observed in: https://android-review.googlesource.com/c/kernel/common/+/3877981 because the entire community tends to enable large folios unconditionally if possible. Without enough clarification, even I merge this, there will be endless questions again and again about this. And Jan once raised up if it should be a user interface or auto-tuning one: https://lore.kernel.org/r/z2ule3ilnnpoevo5mvt3intvjtuyud7vg3pbfauon47fhr4owa@giaehpbie4a5 My question is that if the needs are real, I wonder if it should be a vfs generic decision instead (because it's not due to the filesystem restriction but due to real system memory pressure or heavy workload for example). However, if the answer is that others don't really care about this, I'm fine to leave it as an erofs-specific option as long as the actual case is clear in the commit message. Thanks, Gao Xiang > > Signed-off-by: Chao Yu > --- > Documentation/filesystems/erofs.rst | 1 + > fs/erofs/inode.c | 3 ++- > fs/erofs/internal.h | 1 + > fs/erofs/super.c | 8 +++++++- > 4 files changed, 11 insertions(+), 2 deletions(-) > > diff --git a/Documentation/filesystems/erofs.rst b/Documentation/filesystems/erofs.rst > index fe06308e546c..d692a1d9f32c 100644 > --- a/Documentation/filesystems/erofs.rst > +++ b/Documentation/filesystems/erofs.rst > @@ -137,6 +137,7 @@ fsoffset=%llu Specify block-aligned filesystem offset for the primary d > inode_share Enable inode page sharing for this filesystem. Inodes with > identical content within the same domain ID can share the > page cache. > +nolargefolio Disable large folio support for all files. > =================== ========================================================= > > Sysfs Entries > diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c > index 4b3d21402e10..26361e86a354 100644 > --- a/fs/erofs/inode.c > +++ b/fs/erofs/inode.c > @@ -254,7 +254,8 @@ static int erofs_fill_inode(struct inode *inode) > return 0; > } > > - mapping_set_large_folios(inode->i_mapping); > + if (!test_opt(&EROFS_SB(inode->i_sb)->opt, NO_LARGE_FOLIO)) > + mapping_set_large_folios(inode->i_mapping); > aops = erofs_get_aops(inode, false); > if (IS_ERR(aops)) > return PTR_ERR(aops); > diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h > index a4f0a42cf8c3..b5d98410c699 100644 > --- a/fs/erofs/internal.h > +++ b/fs/erofs/internal.h > @@ -177,6 +177,7 @@ struct erofs_sb_info { > #define EROFS_MOUNT_DAX_NEVER 0x00000080 > #define EROFS_MOUNT_DIRECT_IO 0x00000100 > #define EROFS_MOUNT_INODE_SHARE 0x00000200 > +#define EROFS_MOUNT_NO_LARGE_FOLIO 0x00000400 > > #define clear_opt(opt, option) ((opt)->mount_opt &= ~EROFS_MOUNT_##option) > #define set_opt(opt, option) ((opt)->mount_opt |= EROFS_MOUNT_##option) > diff --git a/fs/erofs/super.c b/fs/erofs/super.c > index 972a0c82198d..a353369d4db8 100644 > --- a/fs/erofs/super.c > +++ b/fs/erofs/super.c > @@ -390,7 +390,7 @@ static void erofs_default_options(struct erofs_sb_info *sbi) > enum { > Opt_user_xattr, Opt_acl, Opt_cache_strategy, Opt_dax, Opt_dax_enum, > Opt_device, Opt_fsid, Opt_domain_id, Opt_directio, Opt_fsoffset, > - Opt_inode_share, > + Opt_inode_share, Opt_nolargefolio, > }; > > static const struct constant_table erofs_param_cache_strategy[] = { > @@ -419,6 +419,7 @@ static const struct fs_parameter_spec erofs_fs_parameters[] = { > fsparam_flag_no("directio", Opt_directio), > fsparam_u64("fsoffset", Opt_fsoffset), > fsparam_flag("inode_share", Opt_inode_share), > + fsparam_flag("nolargefolio", Opt_nolargefolio), > {} > }; > > @@ -541,6 +542,9 @@ static int erofs_fc_parse_param(struct fs_context *fc, > else > set_opt(&sbi->opt, INODE_SHARE); > break; > + case Opt_nolargefolio: > + set_opt(&sbi->opt, NO_LARGE_FOLIO); > + break; > } > return 0; > } > @@ -1105,6 +1109,8 @@ static int erofs_show_options(struct seq_file *seq, struct dentry *root) > seq_printf(seq, ",fsoffset=%llu", sbi->dif0.fsoff); > if (test_opt(opt, INODE_SHARE)) > seq_puts(seq, ",inode_share"); > + if (test_opt(opt, NO_LARGE_FOLIO)) > + seq_puts(seq, ",nolargefolio"); > return 0; > } >