Re: Proposal: make RAID6 code optional

From: H. Peter Anvin
Date: Wed Apr 22 2009 - 14:40:27 EST


Andre Noll wrote:
On 10:23, H. Peter Anvin wrote:

We could use vmalloc() and generate the tables at initialization time.
However, having a separate module which exports the raid6 declaration
and uses the raid5 module as a subroutine library seems easier.

Really? Easier than keeping only two 256-byte arrays for exp() and
log() and use these at runtime to populate the (dynamically allocated)
64K GF multiplication table? That seems to be really simple and would
still shave off 64K of kernel memory for raid5-only users.


Yes, I believe it would be easier than having dynamically allocated arrays. Dynamically generated arrays using static memory allocations (bss) is one thing, but that would only reduce size of the module on disk, which I don't think anyone considers a problem.

-hpa

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