Re: Memory allocator semantics

From: Christoph Lameter
Date: Tue Feb 11 2014 - 13:44:54 EST


On Tue, 11 Feb 2014, Pekka Enberg wrote:

> So again, there's nothing in (A) that the memory allocator is
> concerned about. kmalloc() makes no guarantees whatsoever about the
> visibility of "r1" across CPUs. If you're saying that there's an
> implicit barrier between kmalloc() and kfree(), that's an unintended
> side-effect, not a design decision AFAICT.

I am not sure that this side effect necessarily happens. The SLUB fastpath
does not disable interrupts and only uses a cmpxchg without lock
semantics.

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