[Ocfs2-devel] Re: [PATCH] Dynamic lockres hash table

[Sunil Mushran]

Look it at as a short term fix considering sles is shipping next
month and we won't have the time to do the dynamic resizing.

As far as dynamic resizing goes, if we provide info indicating that
the lookups are slow and that they can speeded up by increasing
the hash... we can not only let the user do it manually but at some
point resize it automatically too.

Mark Fasheh wrote:
> On Tue, Mar 04, 2008 at 06:33:03PM -0800, Sunil Mushran wrote:
>   
>> My main problem with a mount option is that it is not dynamic.
>>
>> I was thinking along lines of having a sysfs param that will
>> allow users to dynamically resize the number of pages alloted
>> to the hash. This will definitely require us running tests to see
>> how long it takes to rehash with 500K lockres under the
>> dlm_spinlock.
>>     
>
> I like the idea of being able to change it on the fly, but I'm wondering
> about how useful that ability will be for customers versus just being able
> to set it at mount time.
>
>
>   
>> I guess as a first step, we should add a avg lookup time stat.
>>
>> But all this will take time.
>>
>> How about we increase the defaults in 1.4 from 4 pages to 16 or
>> even 32 pages. This will be for Enterprise Kernels only and we
>> should be able to assume that they will have 128K per mount to
>> spare.
>>     
>
> Please, can we solve this everywhere instead of having some ocfs2 1.4
> specific hack.
> 	--Mark
>
> --
> Mark Fasheh
> Principal Software Developer, Oracle
> mark.fasheh at oracle.com
>