Messages in this thread | | | From | (Eric W. Biederman) | Subject | Re: [PATCH] x86_64: Make NR_IRQS configurable in Kconfig | Date | Mon, 07 Aug 2006 11:46:25 -0600 |
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"H. Peter Anvin" <hpa@zytor.com> writes:
> Eric W. Biederman wrote: >> a) Because I would like to flush out bugs. >> b) Because I want a default that works for everyone. >> c) Because with MSI we have a potential for large irq counts on most systems. >> d) Because anyone who disagrees with me can send a patch and fix >> the default. >> e) Because with the default number of cpus we can very close to needing >> this many irqs in the worst case. >> f) This is much better than previous to my patch and setting NR_CPUS=255 >> and getting 8K IRQS. >> g) Because I probably should have been more inventive than copying the >> NR_IRQS text, but when I did the wording sounded ok to me. >> > > Why not simply reserve 224*NR_CPUS IRQs? If you have 256 CPUs allocating 64K > IRQs should hardly matter :)
Well there is this little matter of 224*NR_CPUS*NR_CPUS counters at that point that I think would be prohibitive for most sane people. Taking 224K of per cpu memory in 256 different per cpu areas.
Still what is 56MB when you have a terrabyte of RAM. :)
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