25 Aug
2008
25 Aug
'08
8:45 a.m.
At Mon, 25 Aug 2008 00:37:52 +0200, Rene Herman wrote:
On 24-08-08 21:48, Krzysztof Helt wrote:
From the Documentation/memory-barriers.txt " (*) inX(), outX(): ... They are guaranteed to be fully ordered with respect to each other.
They are not guaranteed to be fully ordered with respect to other types of memory and I/O operation.... "
No barriers are needed in this case.
On x86 certainly not and I would expect these barriers are there for cases/architectures where inb() and outb() are redefined to memory mapped I/O or there would just be no point at all.
These barriers are mostly for Alpha. Not sure whether they are really needed, though.
Takashi