On 8 August 2012 14:18, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > Il 08/08/2012 15:09, Stefan Hajnoczi ha scritto: >> No need to roll our own or copy the implementation from the kernel. > > To some extent we need to because: > > 1. GCC atomics look ugly, :) do not provide rmb/wmb, and in some > versions of GCC mb is known to be (wrongly) a no-op. > > 2. glib atomics do not provide mb/rmb/wmb either, and > g_atomic_int_get/g_atomic_int_set are inefficient: they add barriers > everywhere, while it is clearer if you put barriers manually, and you > often do not need barriers in the get side. glib atomics also do not > provide xchg. These are arguments in favour of "don't try to use atomic ops" -- if serious large projects like GCC and glib can't produce working efficient implementations for all target architectures, what chance do we have? -- PMM -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
