Re: [PATCH 03/10] jump label v11: base patch

Andi Kleen
2010-09-21T19:49:05Z

> I agree with Steven, Peter and Jason: due to the large amount of
> tracepoints we can end up patching, we should keep the hash tables. This

I suspect when it's cache cold the hash tables will be actually slower.
As a general rule memory bloat = slow.

> code is very similar to what I have in the tracepoints already and in
> the immediate values. So this code is solid and has been tested over a
> large user base for quite some time already.

FWIW "We always did it this way" is not a good argument
in engineering discussions.

> One change I would recommend is to use a separate memory pool to
> allocate the struct jump_label_entry, to favor better locality. I did
> not do it in tracepoints and markers because each entry have a variable
> length, but given that struct jump_label_entry seems to be fixed-size,
> then we should definitely go for a kmem_cache_alloc().

Yes even more complexity, great idea.

-Andi
--
ak@linux.intel.com -- Speaking for myself only.