From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.4]) (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 E8F753C0633; Fri, 8 May 2026 09:35:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.4 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778232936; cv=none; b=e+iGiekJ68Rd5hHSmeqkMd8RmbROiSbsyJ3ODQqhVHzciR186Odlh40DPfhM5jBO3yq/9o22iOO0H302zCkh/vcZ/wu4w9fxzt4Lk4wWOdLnmT8reK07uKJE25VS4cbClO/prejKMQIAhJiwrMO1xEmOT7SlvB5435zQDI4vwn8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778232936; c=relaxed/simple; bh=iLEMVuIUAYNxQld7HNPZ4x6eyg9UYHHvPCzN+/WuXjo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Gjbp7IwQ+ZERsr9SZqyBw9vA5RQAJigeiXTIAsIMsVHc2G5EJ2l956b7Wd/8XV8EI3rriyA42o0nrCq3e5gVNZvZI3inAZAnGE3lwWJ6JDvw8wsbbX0iWEogN/megIDCfBBZ0WYcbRMxODq0w5aYAw7Uv4x96VBAdiof30qSjss= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=Ef0SfN4O; arc=none smtp.client-ip=220.197.31.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="Ef0SfN4O" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-ID:MIME-Version; bh=Ho x6VtJtqn/K6Bdh5hfLYu35wGS6LKEAxmhmuB+uoe4=; b=Ef0SfN4OpTU0tKeQ56 8+1ipUPsd6CmNBgVdtL4bv5FZlljgs2yrJYDGk5OV0ImkZzk+BCxS2XUKZExjp1U gl0VcFR5tpWj1cYdoE5ZCXGFPr8va9Gqqig+0fSZ+SDZFWq1cry6Xdy8Z5CJ3X/0 FlFizDrIpUc1YRDjXekWpuT8g= Received: from liubaolin-VMware-Virtual-Platform.localdomain (unknown []) by gzsmtp2 (Coremail) with SMTP id PSgvCgDXeCEprv1pUW9wDg--.60442S4; Fri, 08 May 2026 17:34:56 +0800 (CST) From: Baolin Liu To: tytso@mit.edu, adilger.kernel@dilger.ca, libaokun@linux.alibaba.com Cc: ojaswin@linux.ibm.com, ritesh.list@gmail.com, yi.zhang@huawei.com, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, wangguanyu@vivo.com, adilger@dilger.ca, liubaolin12138@163.com, Baolin Liu Subject: [PATCH v4 v4 2/3] ext4: use atomic operations for s_mb_stats accesses Date: Fri, 8 May 2026 17:34:27 +0800 Message-ID: <20260508093428.5814-3-liubaolin12138@163.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260508093428.5814-1-liubaolin12138@163.com> References: <20260508093428.5814-1-liubaolin12138@163.com> Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:PSgvCgDXeCEprv1pUW9wDg--.60442S4 X-Coremail-Antispam: 1Uf129KBjvJXoW3ArWkAw4rtry5Ww48tr4UCFg_yoWxAFWxpr srZFyUAr48Zw18uF4DWa98W3Z5K3y0k347Jr4S934fuFyavFyFyasaqFyUAFyDArWDAFn5 Z3yqyrWDGrWIka7anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0zNiifUUUUUU= X-CM-SenderInfo: xolxutxrol0iasrtmqqrwthudrp/xtbC6QCVYGn9rkB+7gAA32 From: Baolin Liu s_mb_stats can be read from mballoc paths while being updated through sysfs, which can race. Convert it to atomic_t and use atomic_read()/atomic_set() for all accesses. Signed-off-by: Baolin Liu --- fs/ext4/ext4.h | 2 +- fs/ext4/mballoc.c | 24 ++++++++++++------------ fs/ext4/sysfs.c | 9 ++++++++- 3 files changed, 21 insertions(+), 14 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 293f698b7042..04bccfcb018e 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1624,7 +1624,7 @@ struct ext4_sb_info { unsigned int s_mb_stream_request; unsigned int s_mb_max_to_scan; unsigned int s_mb_min_to_scan; - unsigned int s_mb_stats; + atomic_t s_mb_stats; unsigned int s_mb_order2_reqs; unsigned int s_mb_group_prealloc; unsigned int s_max_dir_size_kb; diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 1e13ef62cb9d..95103fbc1583 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -924,7 +924,7 @@ static int ext4_mb_scan_groups_xa_range(struct ext4_allocation_context *ac, xa_for_each_range(xa, group, grp, start, end - 1) { int err; - if (sbi->s_mb_stats) + if (atomic_read(&sbi->s_mb_stats)) atomic64_inc(&sbi->s_bal_cX_groups_considered[cr]); err = ext4_mb_scan_group(ac, grp->bb_group); @@ -980,7 +980,7 @@ static int ext4_mb_scan_groups_p2_aligned(struct ext4_allocation_context *ac, goto wrap_around; } - if (sbi->s_mb_stats) + if (atomic_read(&sbi->s_mb_stats)) atomic64_inc(&sbi->s_bal_cX_failed[ac->ac_criteria]); /* Increment cr and search again if no group is found */ @@ -1031,7 +1031,7 @@ static int ext4_mb_scan_groups_goal_fast(struct ext4_allocation_context *ac, goto wrap_around; } - if (sbi->s_mb_stats) + if (atomic_read(&sbi->s_mb_stats)) atomic64_inc(&sbi->s_bal_cX_failed[ac->ac_criteria]); /* * CR_BEST_AVAIL_LEN works based on the concept that we have @@ -1135,7 +1135,7 @@ static int ext4_mb_scan_groups_best_avail(struct ext4_allocation_context *ac, /* Reset goal length to original goal length before falling into CR_GOAL_LEN_SLOW */ ac->ac_g_ex.fe_len = ac->ac_orig_goal_len; - if (sbi->s_mb_stats) + if (atomic_read(&sbi->s_mb_stats)) atomic64_inc(&sbi->s_bal_cX_failed[ac->ac_criteria]); ac->ac_criteria = CR_GOAL_LEN_SLOW; @@ -1184,7 +1184,7 @@ static int ext4_mb_scan_groups_linear(struct ext4_allocation_context *ac, ac->ac_criteria++; /* Processed all groups and haven't found blocks */ - if (sbi->s_mb_stats && i == ngroups) + if (atomic_read(&sbi->s_mb_stats) && i == ngroups) atomic64_inc(&sbi->s_bal_cX_failed[cr]); return 0; @@ -2535,7 +2535,7 @@ void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac, BUG_ON(ac->ac_f_ex.fe_len != ac->ac_g_ex.fe_len); - if (EXT4_SB(sb)->s_mb_stats) + if (atomic_read(&EXT4_SB(sb)->s_mb_stats)) atomic_inc(&EXT4_SB(sb)->s_bal_2orders); break; @@ -2780,7 +2780,7 @@ static int ext4_mb_good_group_nolock(struct ext4_allocation_context *ac, if (!grp) return -EFSCORRUPTED; - if (sbi->s_mb_stats) + if (atomic_read(&sbi->s_mb_stats)) atomic64_inc(&sbi->s_bal_cX_groups_considered[ac->ac_criteria]); if (should_lock) { ext4_lock_group(sb, group); @@ -3091,7 +3091,7 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac) } } - if (sbi->s_mb_stats && ac->ac_status == AC_STATUS_FOUND) { + if (atomic_read(&sbi->s_mb_stats) && ac->ac_status == AC_STATUS_FOUND) { atomic64_inc(&sbi->s_bal_cX_hits[ac->ac_criteria]); if (ac->ac_flags & EXT4_MB_STREAM_ALLOC && ac->ac_b_ex.fe_group == ac->ac_g_ex.fe_group) @@ -3204,7 +3204,7 @@ int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset) struct ext4_sb_info *sbi = EXT4_SB(sb); seq_puts(seq, "mballoc:\n"); - if (!sbi->s_mb_stats) { + if (!atomic_read(&sbi->s_mb_stats)) { seq_puts(seq, "\tmb stats collection turned off.\n"); seq_puts( seq, @@ -3783,7 +3783,7 @@ int ext4_mb_init(struct super_block *sb) sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN; sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN; - sbi->s_mb_stats = MB_DEFAULT_STATS; + atomic_set(&sbi->s_mb_stats, MB_DEFAULT_STATS); sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD; sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS; sbi->s_mb_best_avail_max_trim_order = MB_DEFAULT_BEST_AVAIL_TRIM_ORDER; @@ -3929,7 +3929,7 @@ void ext4_mb_release(struct super_block *sb) kfree(sbi->s_mb_offsets); kfree(sbi->s_mb_maxs); iput(sbi->s_buddy_cache); - if (sbi->s_mb_stats) { + if (atomic_read(&sbi->s_mb_stats)) { ext4_msg(sb, KERN_INFO, "mballoc: %u blocks %u reqs (%u success)", atomic_read(&sbi->s_bal_allocated), @@ -4694,7 +4694,7 @@ static void ext4_mb_collect_stats(struct ext4_allocation_context *ac) { struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb); - if (sbi->s_mb_stats && ac->ac_g_ex.fe_len >= 1) { + if (atomic_read(&sbi->s_mb_stats) && ac->ac_g_ex.fe_len >= 1) { atomic_inc(&sbi->s_bal_reqs); atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated); if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len) diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c index b87d7bdab06a..0f65ab372dee 100644 --- a/fs/ext4/sysfs.c +++ b/fs/ext4/sysfs.c @@ -250,7 +250,7 @@ EXT4_ATTR_OFFSET(mb_best_avail_max_trim_order, 0644, mb_order, ext4_sb_info, s_mb_best_avail_max_trim_order); EXT4_ATTR_OFFSET(err_report_sec, 0644, err_report_sec, ext4_sb_info, s_err_report_sec); EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal); -EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats); +EXT4_ATTR_OFFSET(mb_stats, 0644, pointer_atomic, ext4_sb_info, s_mb_stats); EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan); EXT4_RW_ATTR_SBI_UI(mb_min_to_scan, s_mb_min_to_scan); EXT4_RW_ATTR_SBI_UI(mb_order2_req, s_mb_order2_reqs); @@ -493,6 +493,7 @@ static ssize_t ext4_generic_attr_store(struct ext4_attr *a, const char *buf, size_t len) { int ret; + int i; unsigned int t; unsigned long lt; void *ptr = calc_ptr(a, sbi); @@ -540,6 +541,12 @@ static ssize_t ext4_generic_attr_store(struct ext4_attr *a, return ret; *((unsigned long *) ptr) = lt; return len; + case attr_pointer_atomic: + ret = kstrtoint(skip_spaces(buf), 0, &i); + if (ret) + return ret; + atomic_set((atomic_t *)ptr, i); + return len; } return 0; } -- 2.51.0