Lee,
--- On Mon, 4/19/10, Lee Schermerhorn <Lee.Schermerhorn@xxxxxx> wrote:
> You should never change the system default once the system
> is up and
> running.
>
Not sure what I was thinking.Agreed, we should leave the default-policy alone.
> Still not clear on what your requirements are
Thanks for pointing me to the other post. I might have a similar problem.I've a nehalem box.
1) Drivers supports MSI-X.
1.1) Drivers at load time allocate a chunk of DMA'able memory.
2) Sometime later, after the OS boots, I need to load my apps.
3) Now, the apps and the drivers communicate via a mmap'd region.
I need a deterministic way of allocating memory depending on my needs(interleave or localalloc).So I can't be at the mercy of either 'current' or 'global-policy' or anyone else.Also, why reference 'current' to begin with? And everytime I reference 'current' from within my driver, current points to 'work_for_cpu' kthread. So that clearly doesn't help.
> A device-centric interface--e.g.,
> 'get_free_pages_dev()'--could get the
> device/bus node affinity via dev_to_node() and then do the
> allocation/conversion. I think this is
> close to what you're suggesting
> above. See dma_generic_alloc_coherent() [in
> arch/x86/kernel/pci-dma.c]
> for an example of a wrapper that does the device affinity
> lookup and
> allocation in one function.
>
> Of course, you could just do this in your driver, as well.
>
Very helpful thanks.I will mimic 'dma_generic_alloc_coherent' in my driver when I need local-node memory.
> > Also, is there a way to configure irqbalance and ask
> it to leave these
> > guys alone? Like a config file that says - leave
> these
> > irqs/pci-devices alone.For now I've shut down
> irqbalance.
>
> You can set the environment variable
> IRQBALANCE_BANNED_INTERRUPTS--when
> starting irqbalance--to list of interrupts that irqbalance
> should ignore
> if you're using a version that supports that. Check
> the init script
> that starts irqbalance on your distro of choice.
>
aaaah...mine is old and I could see IRQBALANCE_BANNED_CPUS and not _INTERRUPTS.I will upgrade it.
> Regards,
> Lee
Thanks
Chetan Loke
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