[Ocfs2-tools-devel] [PATCH 2/2] looped chain - Break loop in fsck

[tristan ye]

Goldwyn Rodrigues wrote:
> Hi Tristan,
>
> On Fri, Mar 5, 2010 at 9:56 AM, Goldwyn Rodrigues <rgoldwyn at gmail.com> wrote:
>   
>> Hi Tristan,
>>
>>
>> On Fri, Mar 5, 2010 at 8:44 AM, tristan ye <tristan.ye at oracle.com> wrote:
>>
>>     
> <snip>
>
>   
>>> Let me know if you have some other suggestions on it.
>>>       
>
> On second thoughts, in an un-cached environment, your algorithm would
> have more number of disk reads as compared to my algorithm. So, a
> cached environment might be better, but will consume more memory. I am
> not sure how you would want to handle this efficiently.
>   

Yes, your time complexity of disk reads is O(N), while mine is O(2N), it 
we disgard the cache.

So the problem is 'Your extra collection/comparions' VS 'My extra disk 
reads', the best way I guess is to compare their efficiency  in a real 
world after we drop all buffer and caches. by doing:

1. echo 3>/proc/sys/vm/drop_caches

2. time fsck...


The winner will be consuming less time.

Joel, sunil,

How do you think about that issue?


> Even, in my algorithm, it can be improvised by collecting the block
> numbers in the check_chain loop itself, but lets face it... how often
> do you get a loop in the chain to do this? We don't want to have
> multiple collections/comparisons for all chains checked.
>
> Always a yin and yang :)
>
> Regards,
>
>