From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) (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 43D0B14AA9; Sat, 8 Mar 2025 02:25:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.189 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741400761; cv=none; b=Sl5FvC2Ynt3JFNDBgyfQFH95jyg6z9du8qPecjxOtlt1F+0Ntl6FflLJL5aG3vKt+71M9IKho3FoaTPUPlE3nJ+mJEVnIGKfYfmh9w+Euh49ZRLjyXiLhTp0bziknqp3PjcCZ3XgJ2+TZEVuIzWFy9GcCK4Lbrxt394QUYrL37A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741400761; c=relaxed/simple; bh=BbyM1FMugdVrT11eiLsPsPBr3Y8rT+rtxvAokEU7dNU=; h=Message-ID:Date:MIME-Version:Subject:To:CC:References:From: In-Reply-To:Content-Type; b=GWv25dyjYtYQM6XbP0MZysyxNXr+YIgvtgdDS2ym2sSm928RDLGg3g6EqlY/y+la9yj/+J8TFH0Rz8GMKxGhpk3JL84bLJc3WIA6piVtTc30ycY4r4EWJCYEwGMpX+YPyhZevgJgBRE7s7jh6PBI8Bqfy7ZFp6+SSltOHgCVZ2I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.189 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.88.194]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4Z8n4Q1LsWz9wP9; Sat, 8 Mar 2025 10:22:46 +0800 (CST) Received: from kwepemg500008.china.huawei.com (unknown [7.202.181.45]) by mail.maildlp.com (Postfix) with ESMTPS id 50E00140380; Sat, 8 Mar 2025 10:25:55 +0800 (CST) Received: from [127.0.0.1] (10.174.177.71) by kwepemg500008.china.huawei.com (7.202.181.45) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Sat, 8 Mar 2025 10:25:54 +0800 Message-ID: <6ab6dba8-c15e-49e8-966f-63a6e2df0590@huawei.com> Date: Sat, 8 Mar 2025 10:25:53 +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 Subject: Re: [PATCH v2 3/3] ext4: Make sb update interval tunable To: Ojaswin Mujoo CC: , Theodore Ts'o , Jan Kara , , "Ritesh Harjani (IBM)" , Yang Erkun References: <4c89be10ad8c8937048148bce1fc9ca882d060c6.1741270780.git.ojaswin@linux.ibm.com> Content-Language: en-US From: Baokun Li In-Reply-To: <4c89be10ad8c8937048148bce1fc9ca882d060c6.1741270780.git.ojaswin@linux.ibm.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemg500008.china.huawei.com (7.202.181.45) On 2025/3/6 22:28, Ojaswin Mujoo wrote: > Currently, outside error paths, we auto commit the super block after 1 > hour has passed and 16MB worth of updates have been written since last > commit. This is a policy decision so make this tunable while keeping the > defaults same. This is useful if user wants to tweak the superblock > behavior or for debugging the codepath by allowing to trigger it more > frequently. > > We can now tweak the super block update using sb_update_sec and > sb_update_kb files in /sys/fs/ext4// > > Reviewed-by: Jan Kara > Reviewed-by: Ritesh Harjani (IBM) > Signed-off-by: Ojaswin Mujoo Looks good. Reviewed-by: Baokun Li > --- > fs/ext4/ext4.h | 9 +++++++++ > fs/ext4/super.c | 15 ++++++++------- > fs/ext4/sysfs.c | 4 ++++ > 3 files changed, 21 insertions(+), 7 deletions(-) > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > index d48e93bd5690..82c902ed86f3 100644 > --- a/fs/ext4/ext4.h > +++ b/fs/ext4/ext4.h > @@ -1608,6 +1608,8 @@ struct ext4_sb_info { > unsigned int s_mb_prefetch; > unsigned int s_mb_prefetch_limit; > unsigned int s_mb_best_avail_max_trim_order; > + unsigned int s_sb_update_sec; > + unsigned int s_sb_update_kb; > > /* stats for buddy allocator */ > atomic_t s_bal_reqs; /* number of reqs with len > 1 */ > @@ -2281,6 +2283,13 @@ static inline int ext4_forced_shutdown(struct super_block *sb) > #define EXT4_DEF_MIN_BATCH_TIME 0 > #define EXT4_DEF_MAX_BATCH_TIME 15000 /* 15ms */ > > +/* > + * Default values for superblock update > + */ > +#define EXT4_DEF_SB_UPDATE_INTERVAL_SEC (3600) /* seconds (1 hour) */ > +#define EXT4_DEF_SB_UPDATE_INTERVAL_KB (16384) /* kilobytes (16MB) */ > + > + > /* > * Minimum number of groups in a flexgroup before we separate out > * directories into the first block group of a flexgroup > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index 31552cf0519a..1b47b111c583 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -447,9 +447,6 @@ static time64_t __ext4_get_tstamp(__le32 *lo, __u8 *hi) > #define ext4_get_tstamp(es, tstamp) \ > __ext4_get_tstamp(&(es)->tstamp, &(es)->tstamp ## _hi) > > -#define EXT4_SB_REFRESH_INTERVAL_SEC (3600) /* seconds (1 hour) */ > -#define EXT4_SB_REFRESH_INTERVAL_KB (16384) /* kilobytes (16MB) */ > - > /* > * The ext4_maybe_update_superblock() function checks and updates the > * superblock if needed. > @@ -457,8 +454,10 @@ static time64_t __ext4_get_tstamp(__le32 *lo, __u8 *hi) > * This function is designed to update the on-disk superblock only under > * certain conditions to prevent excessive disk writes and unnecessary > * waking of the disk from sleep. The superblock will be updated if: > - * 1. More than an hour has passed since the last superblock update, and > - * 2. More than 16MB have been written since the last superblock update. > + * 1. More than sbi->s_sb_update_sec (def: 1 hour) has passed since the last > + * superblock update > + * 2. More than sbi->s_sb_update_kb (def: 16MB) kbs have been written since the > + * last superblock update. > * > * @sb: The superblock > */ > @@ -479,7 +478,7 @@ static void ext4_maybe_update_superblock(struct super_block *sb) > now = ktime_get_real_seconds(); > last_update = ext4_get_tstamp(es, s_wtime); > > - if (likely(now - last_update < EXT4_SB_REFRESH_INTERVAL_SEC)) > + if (likely(now - last_update < sbi->s_sb_update_sec)) > return; > > lifetime_write_kbytes = sbi->s_kbytes_written + > @@ -494,7 +493,7 @@ static void ext4_maybe_update_superblock(struct super_block *sb) > */ > diff_size = lifetime_write_kbytes - le64_to_cpu(es->s_kbytes_written); > > - if (diff_size > EXT4_SB_REFRESH_INTERVAL_KB) > + if (diff_size > sbi->s_sb_update_kb) > schedule_work(&EXT4_SB(sb)->s_sb_upd_work); > } > > @@ -5246,6 +5245,8 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) > sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ; > sbi->s_min_batch_time = EXT4_DEF_MIN_BATCH_TIME; > sbi->s_max_batch_time = EXT4_DEF_MAX_BATCH_TIME; > + sbi->s_sb_update_kb = EXT4_DEF_SB_UPDATE_INTERVAL_KB; > + sbi->s_sb_update_sec = EXT4_DEF_SB_UPDATE_INTERVAL_SEC; > > /* > * set default s_li_wait_mult for lazyinit, for the case there is > diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c > index ddb54608ca2e..987bd00f916a 100644 > --- a/fs/ext4/sysfs.c > +++ b/fs/ext4/sysfs.c > @@ -254,6 +254,8 @@ EXT4_ATTR(journal_task, 0444, journal_task); > EXT4_RW_ATTR_SBI_UI(mb_prefetch, s_mb_prefetch); > EXT4_RW_ATTR_SBI_UI(mb_prefetch_limit, s_mb_prefetch_limit); > EXT4_RW_ATTR_SBI_UL(last_trim_minblks, s_last_trim_minblks); > +EXT4_RW_ATTR_SBI_UI(sb_update_sec, s_sb_update_sec); > +EXT4_RW_ATTR_SBI_UI(sb_update_kb, s_sb_update_kb); > > static unsigned int old_bump_val = 128; > EXT4_ATTR_PTR(max_writeback_mb_bump, 0444, pointer_ui, &old_bump_val); > @@ -305,6 +307,8 @@ static struct attribute *ext4_attrs[] = { > ATTR_LIST(mb_prefetch), > ATTR_LIST(mb_prefetch_limit), > ATTR_LIST(last_trim_minblks), > + ATTR_LIST(sb_update_sec), > + ATTR_LIST(sb_update_kb), > NULL, > }; > ATTRIBUTE_GROUPS(ext4);