From: Liu Bo <bo.li.liu@oracle.com>
To: miaox@cn.fujitsu.com
Cc: Linux Btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: [PATCH 0/3] flush delalloc by multi-task
Date: Fri, 26 Oct 2012 15:01:54 +0800 [thread overview]
Message-ID: <508A3562.9040006@oracle.com> (raw)
In-Reply-To: <508A02BF.10502@cn.fujitsu.com>
On 10/26/2012 11:25 AM, Miao Xie wrote:
> On Fri, 26 Oct 2012 10:05:55 +0800, Liu Bo wrote:
>> On 10/26/2012 09:56 AM, Miao Xie wrote:
>>>> I can see the potential improvements brought by flushing inodes this way.
>>>>>
>>>>> But I don't think it makes much sense by making waiting process multi-task,
>>>>> since even we spread wait order extents into different cpus, they just occpied
>>>>> the cpu and went on waiting and scheduled then, I mean, the bottleneck is on
>>>>> what we're waiting for.
>>> Thanks for your comment, I think only btrfs_run_ordered_operations(root, 0) needn't
>>> wait for the works, the others must wait.
>>>
>>> The first reason is to avoid changing the semantic of those tree function. The second
>>> reason is we have to wait for the completion of all works, if not, the file data in
>>> snapshots may be different with the source suvolumes because the flush may not end
>>> before the snapshot creation.
>>>
>>
>> Yes, it's right that they must wait for all workers to finish.
>>
>> But I don't mean that(sorry for my confusing words).
>>
>> IMO we don't need to let *btrfs_wait_ordered_extents()* run as multi-task.
>
> It also need to be done by multi-task because btrfs_wait_ordered_extents() doesn't imply
> that all the dirty pages in the ordered extent have been written into the disk, that is
> it also need do lots of things before waiting for the event - BTRFS_ORDERED_COMPLETE, so
> the multi-task process is useful, I think.
>
Well, I missed the flushing part.
> Anyway, we need test to validate it.
>
> Thanks
> Miao
>
>>
>> thanks,
>> liubo
>>
>>
>>
>>
>
>
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next prev parent reply other threads:[~2012-10-26 7:02 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-25 9:20 [PATCH 0/3] flush delalloc by multi-task Miao Xie
2012-10-25 9:28 ` [PATCH 1/3] Btrfs: make delalloc inodes be flushed " Miao Xie
2012-10-25 9:31 ` [PATCH 2/3] Btrfs: make ordered operations be handled " Miao Xie
2012-10-25 9:41 ` [PATCH 3/3] Btrfs: make ordered extent be flushed " Miao Xie
2012-10-25 11:53 ` [PATCH 0/3] flush delalloc " Liu Bo
2012-10-26 1:56 ` Miao Xie
2012-10-26 2:05 ` Liu Bo
2012-10-26 3:25 ` Miao Xie
2012-10-26 7:01 ` Liu Bo [this message]
2012-11-01 7:43 ` Miao Xie
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