Re: What does atomic_read actually do?

From: Brian Gerst
Date: Sat Dec 18 2004 - 16:05:26 EST

Joseph Seigh wrote:
On Sat, 18 Dec 2004 20:54:40 +0100, Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:

On Sat, 2004-12-18 at 14:20 -0500, Joseph Seigh wrote:

I mean atomic in the either old or new sense. I'm wondering what
the atomicity. Not the C standard. I can see the gcc compiler uses a MOV
instruction to load the atomic_t from memory which is guaranteed atomic by
the architecture if aligned properly. But gcc does that for any old int
as far as I can see, so why use atomic_read?

it does so on *x86

Is this documented for gcc anywhere? Just because it does so doesn't
mean it's guaranteed.

Joe Seigh

Chapter 7, section 1

Brian Gerst
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