Re: [PATCH v4 19/43] hpsa: add ioaccel sg chaining for the ioaccel2 path

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On 04/22/2015 09:12 PM, brace wrote:
> The last I read about mempools was from:
> Linux Device Drivers
>  By Jonathan Corbet, Alessandro Rubini, Greg Kroah-Hartman
> 
> https://lwn.net/images/pdf/LDD3/ch08.pdf
> 
> 
> If  you  are  considering  using  a  mempool  in  your  driver,  please  keep  one  thing  in
> mind: mempools allocate a chunk of memory that sits in a list, idle and unavailable
> for any real use. It is easy to consume a great deal of memory with mempools. In
> almost every case, the preferred alternative is to do without the mempool and simply
> deal with the possibility of allocation failures instead. If there is any way for your
> driver to respond to an allocation failure in a way that does not endanger the integ-
> rity of the system, do things that way. Use of mempools in driver code should be
> rare
> 
> But this book is now quite old in Linux terms.
> 
> So, I can investigate using mempools. However, I would prefer to continue using the existing methods in this current patchset.
> 
> I hope that is ok with you...
> 
Yes, that's okay with me.

Personally I would be using mempools when you need lots of small,
frequently changed allocations (like sg elements), and kzalloc() for
large or infrequently changed bits of memory.

Reviewed-by: Hannes Reinecke <hare@xxxxxxx>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		               zSeries & Storage
hare@xxxxxxx			               +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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