linux-ext4 - Re: [PATCH] Set the initial TRIM information as TRIMMED

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAH9JG2XectT=vFBF04EaLtb-8xsuze1gAVs5jH6jb9qbHG7B4g@mail.gmail.com>
Date:	Thu, 1 Dec 2011 17:39:07 +0900
From:	Kyungmin Park <kmpark@...radead.org>
To:	Tao Ma <tm@....ma>
Cc:	tytso@....edu, linux-ext4@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Set the initial TRIM information as TRIMMED

On 12/1/11, Tao Ma <tm@....ma> wrote:
> On 12/01/2011 04:19 PM, Kyungmin Park wrote:
>> On 12/1/11, Tao Ma <tm@....ma> wrote:
>>> Hi Kyungmin,
>>> On 12/01/2011 03:00 PM, Kyungmin Park wrote:
>>>> From: Kyungmin Park <kyungmin.park@...sung.com>
>>>>
>>>> Now trim information doesn't stored at disk so every boot time. it's
>>>> cleared.
>>>> and do the trim all disk groups.
>>>> But assume that it's already trimmed at previous time so don't need to
>>>> trim it again. So set the intial state as trimmed.
>>> sorry, I don't get your meaning here.
>>> Why can we assume that the group is already trimmed since it isn't
>>> stored in the disk?
>> To avoid the first time trim operation.
>> Every boot time. run the fitrim then it trims all block groups again.
>> but it's already done at previous time. so don't need to trim it
>> again.
>> Doesn't make sense? I think it's not designed behavior.
> You make the assumption that we run the fitrim every time at boot time.
> But what if the user don't run it at all? I guess "run fitrim during
> boot" is your firmware's behaviour and it isn't an assumption for all
> the other users.
>
> Having said that, this flag will be cleared whenever some
> blocks/clusters are freed. So maybe it doesn't matter for setting this
> flag during the group initialization.
Right,

I hope trim the real updated blocks only.

Thank you,
Kyungmin Park
>
> Thanks
> Tao
>>
>> In your patch at http://patchwork.ozlabs.org/patch/102918/
>>
>> with the patch:
>> [root@...u-tm linux-2.6]# time ./ftrim /mnt/ext4/a
>> real	0m5.625s
>> user	0m0.000s
>> sys	0m1.269s
>> [root@...u-tm linux-2.6]# time ./ftrim /mnt/ext4/a
>> real	0m0.002s
>> user	0m0.000s
>> sys	0m0.001s
>> [root@...u-tm linux-2.6]# time ./ftrim /mnt/ext4/a
>> real	0m0.002s
>> user	0m0.000s
>> sys	0m0.001s
>>
>> After reboot. it maybe become below
>>
>> [root@...u-tm linux-2.6]# time ./ftrim /mnt/ext4/a
>> real	0m0.002s
>> user	0m0.000s
>> sys	0m0.001s
>> [root@...u-tm linux-2.6]# time ./ftrim /mnt/ext4/a
>> real	0m0.002s
>> user	0m0.000s
>> sys	0m0.001s
>> [root@...u-tm linux-2.6]# time ./ftrim /mnt/ext4/a
>> real	0m0.002s
>> user	0m0.000s
>> sys	0m0.001s
>>
>> Thank you,
>> Kyungmin Park
>>>
>>> Thanks
>>> Tao
>>>>
>>>> Signed-off-by: Kyungmin Park <kyungmin.park@...sung.com>
>>>> ---
>>>> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
>>>> index e2d8be8..97ef342 100644
>>>> --- a/fs/ext4/mballoc.c
>>>> +++ b/fs/ext4/mballoc.c
>>>> @@ -1098,6 +1098,12 @@ int ext4_mb_init_group(struct super_block *sb,
>>>> ext4_group_t group)
>>>>  		goto err;
>>>>  	}
>>>>  	mark_page_accessed(page);
>>>> +
>>>> +	/*
>>>> +	 * TRIM information is not stored at disk so set the initial
>>>> +	 * state as trimmed. Since previous time it's already trimmed all
>>>> +	 */
>>>> +	EXT4_MB_GRP_SET_TRIMMED(this_grp);
>>>>  err:
>>>>  	ext4_mb_put_buddy_page_lock(&e4b);
>>>>  	return ret;
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
>>> the body of a message to majordomo@...r.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@...r.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at  http://www.tux.org/lkml/
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
> the body of a message to majordomo@...r.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html