Re: [PATCH] mm/slab.c : prefetchw the start of new allocated objects

[Ingo Molnar]

* Eric Dumazet <dada1@xxxxxxxxxxxxx> wrote:

>  	local_irq_restore(save_flags);
>  	objp = cache_alloc_debugcheck_after(cachep, flags, objp, __builtin_return_address(0));
> +	prefetchw(objp);
>  	return objp;

the idea is good, but i'd suggest to do the prefetchw a bit earlier, 
right where we calculate objp. Furthermore, it might make sense to only 
trigger the prefetchw in the alloc-miss (non-per-CPU cache) case. There 
it's almost surely a win, in the per-CPU cache case it's not always.

	Ingo
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