Re: [RFC 00/13] smp: reduce stack requirements for genapicsend_IPI_mask functions

From: Ingo Molnar
Date: Sun Sep 07 2008 - 03:37:30 EST



* Mike Travis <travis@xxxxxxx> wrote:

> [Note: all these changes require some more testing but I wanted to
> solicit comments before then, hence the "RFC" in the subject line.
> -thanks! Mike]

these changes are certainly looking very nice.

They do interact with a ton of high-flux topics in -tip, so i'd prefer
to start integrating/testing this straight away (today-ish), before the
target moves yet again. Are there any showstoppers that speak against
that?

The plan would be to not keep this in a single topic but to spread them
into their closest topic (tip/x86/x2apic, tip/irq/sparseirq etc.) - are
there any cross-topic dependencies to be careful about? Most of the
commits seem to be standalone. The debug patch would go into
tip/cpus4096.

And more generally: how far away are we from being able to introduce
struct cpumask and hide its implementation from most .c files? That
would be rather efficient in preventing it from being put on the stack
spuriously in one of the 30+ thousand Linux kernel source code files.
Just like we hide the true structure of things like 'struct kmem_cache'
and force them to always be used as pointers.

Ingo
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