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From: brookxu <brookxu.cn@gmail.com>
To: "Theodore Y. Ts'o" <tytso@mit.edu>
Cc: adilger.kernel@dilger.ca, linux-ext4@vger.kernel.org
Subject: Re: [PATCH RESEND 4/8] ext4: add the gdt block of meta_bg to system_zone
Date: Fri, 4 Dec 2020 09:29:35 +0800	[thread overview]
Message-ID: <6d061665-f66e-9af4-5f91-fe0e4902bce8@gmail.com> (raw)
In-Reply-To: <20201203150841.GM441757@mit.edu>



Theodore Y. Ts'o wrote on 2020/12/3 23:08:
> On Sat, Nov 07, 2020 at 11:58:14PM +0800, Chunguang Xu wrote:
>> From: Chunguang Xu <brookxu@tencent.com>
>>
>> In order to avoid poor search efficiency of system_zone, the
>> system only adds metadata of some sparse group to system_zone.
>> In the meta_bg scenario, the non-sparse group may contain gdt
>> blocks. Perhaps we should add these blocks to system_zone to
>> improve fault tolerance without significantly reducing system
>> performance.
> 
>> @@ -226,13 +227,16 @@ int ext4_setup_system_zone(struct super_block *sb)
>>  
>>  	for (i=0; i < ngroups; i++) {
>>  		cond_resched();
>> -		if (ext4_bg_has_super(sb, i) &&
>> -		    ((i < 5) || ((i % flex_size) == 0))) {
>> -			ret = add_system_zone(system_blks,
>> -					ext4_group_first_block_no(sb, i),
>> -					ext4_bg_num_gdb(sb, i) + 1, 0);
>> -			if (ret)
>> -				goto err;
>> +		if ((i < 5) || ((i % flex_size) == 0)) {
> 
> If we're going to do this, why not just drop the above conditional,
> and just always do this logic for all block groups?

Thanks, in the large disk scenario, if we deal with all groups, the
system_zone will be very large, which may reduce performance. I think
the previous method is good, but it needs to be changed slightly, so
that the fault tolerance in the meta_bg scenario can be improved
without the risk of performance degradation.

>> +			gd_blks = ext4_bg_has_super(sb, i) +
>> +				ext4_bg_num_gdb(sb, i);
>> +			if (gd_blks) {
>> +				ret = add_system_zone(system_blks,
>> +						ext4_group_first_block_no(sb, i),
>> +						gd_blks, 0);
>> +				if (ret)
>> +					goto err;
>> +			}
> 
> 						- Ted
> 

  parent reply	other threads:[~2020-12-04  1:30 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-07 15:58 [PATCH RESEND 1/8] ext4: use ext4_assert() to replace J_ASSERT() Chunguang Xu
2020-11-07 15:58 ` [PATCH RESEND 2/8] ext4: remove redundant mb_regenerate_buddy() Chunguang Xu
2020-12-03 14:42   ` Theodore Y. Ts'o
2020-11-07 15:58 ` [PATCH RESEND 3/8] ext4: simplify the code of mb_find_order_for_block Chunguang Xu
2020-12-03 14:43   ` Theodore Y. Ts'o
2020-11-07 15:58 ` [PATCH RESEND 4/8] ext4: add the gdt block of meta_bg to system_zone Chunguang Xu
2020-12-03 15:08   ` Theodore Y. Ts'o
2020-12-04  1:26     ` brookxu
2020-12-09  4:34       ` Theodore Y. Ts'o
2020-12-09 11:48         ` brookxu
2020-12-09 19:39           ` Theodore Y. Ts'o
2020-12-10 11:00             ` brookxu
2020-12-15  1:14             ` brookxu
2020-12-15 20:13               ` Theodore Y. Ts'o
2020-12-17 16:01                 ` Andreas Dilger
2020-12-04  1:29     ` brookxu [this message]
2020-11-07 15:58 ` [PATCH RESEND 5/8] ext4: update ext4_data_block_valid related comments Chunguang Xu
2020-12-09 19:11   ` Theodore Y. Ts'o
2020-11-07 15:58 ` [PATCH 6/8] ext4: add a helper function to validate metadata block Chunguang Xu
2020-12-09  4:55   ` Theodore Y. Ts'o
2020-12-09 12:12     ` brookxu
2020-11-07 15:58 ` [PATCH RESEND 7/8] ext4: delete invalid code inside ext4_xattr_block_set() Chunguang Xu
2020-12-09 19:24   ` Theodore Y. Ts'o
2020-11-07 15:58 ` [PATCH RESEND 8/8] ext4: fix a memory leak of ext4_free_data Chunguang Xu
2020-12-09 19:29   ` Theodore Y. Ts'o
2020-12-03 14:38 ` [PATCH RESEND 1/8] ext4: use ext4_assert() to replace J_ASSERT() Theodore Y. Ts'o

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