On Wed, 9 Sep 2015, Jesper Dangaard Brouer wrote:

quoted

Hmmm... Guess we need to come up with distinct version of kmalloc() for
irq and non irq contexts to take advantage of that . Most at non irq
context anyways.

I agree, it would be an easy win.  Do notice this will have the most
impact for the slAb allocator.

I estimate alloc + free cost would save:
 * slAb would save approx 60 cycles
 * slUb would save approx  4 cycles

We might consider keeping the slUb approach as it would be more
friendly for RT with less IRQ disabling.

IRQ disabling it a mixed bag. Older cpus have higher latencies there and
also virtualized contexts may require the hypervisor tracks the interrupt
state.

For recent intel cpus this is certainly a workable approach.