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SubjectRe: 2.6 /proc/interrupts fails on systems with many CPUs

On Tue, 11 Nov 2003, Erik Jacobson wrote:
>
> I'm looking for suggestions on how to fix this. I came up with one fix
> that seems to work OK for ia64. I have attached it to this message.
> I'm looking for advice on what should be proposed for the real fix.

This is not the real fix.

Allowing people to use up vmalloc() space by opening the /proc files would
be a major DoS attack. Not worth it.

Instead, just make /proc/interrupts use the proper _sequence_ things, so
that instead of trying to print out everything in one go, you have the
"s_next()" thing to print them out one at a time. The seqfile interfaces
will then do the rigth thing with blocking/caching, and you only need a
single page.

Al - do we have some good documentation of how to use the seq-file
interface?

In the meantime, without documentation, the best place to look is just at
other examples. One such example would be the kernel/kallsyms.c case: see
how it does s_start/s_show/s_next/s_stop (or /proc/slabinfo, or vmstat, or
any number of them).

Linus

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