Re: [PATCH RT 00/02] SLOB optimizations

Eric Dumazet
2005-12-21T07:20:16Z

Ingo Molnar a écrit :
> * Steven Rostedt <rostedt@goodmis.org> wrote:
>
>
>>[...] Today's slab system is starting to become like the IDE where
>>nobody, but a select few sado-masochis, dare to venture in. (I've CC'd
>>them ;) [...]
>
>
> while it could possibly be cleaned up a bit, it's one of the
> best-optimized subsystems Linux has. Most of the "unnecessary
> complexity" in SLAB is related to a performance or a debugging feature.
> Many times i have looked at the SLAB code in a disassembler, right next
> to profile output from some hot workload, and have concluded: 'I couldnt
> do this any better even with hand-coded assembly'.

Well, I miss a version of kmem_cache_alloc()/kmem_cache_free() that wont play
with IRQ masking.

The local_irq_save()/local_irq_restore() pair is quite expensive and could be
avoided for several caches that are exclusively used in process context.

(Not speaking of general caches of course, but caches like dentry_cache, filp,
...)

Eric