Re: HugePages for MD's caches -- can this be done in modern kernel?

["NeilBrown" <neilb@suse.de>]

On Sat, February 7, 2009 6:27 am, Igor Podlesny wrote:
> 2009/2/7 NeilBrown <neilb@suse.de>:
>> On Sat, February 7, 2009 5:08 am, Igor Podlesny wrote:
>>>    Hi!
>>>
>>>    $(Subj). :-)
>>>
>>>    P. S. Also, I deem there lots of structures in kernel that could
>>> benefit
>>> from using HugePages. But this probably a q-n for another kernel list.
>>
>> I have only a vague idea what HugePages are and it is not at all clear
>> to
>> me why you would want to use them for the MD cache.   I assume you are
>>
> 	HugePages requires less TBL entries so they better fit for large
> buffers, as far as I understand.
>
> 	http://unixfoo.blogspot.com/2007/10/hugepages.html
> 	http://linux-mm.org/HugePagesArticles
>
>> talking about MD/RAID456 as that is the only place we use a cache.
>>
> 	Yeah, "stripe_cache_size" setting.
>>
>> Maybe if you could explain what you are thinking....
>>
> 	Yeah, hope this would suffice.

Not really, no.
md does not use "large buffers",  Just lots of little buffers.

NeilBrown