As you mentioned later, "single .c file with all the other files (headers
or other .c files) that it pulls in via #include" is actually "translation
unit", both in the C standard as well as gcc docs. "Compilation unit"
doesn't seem to be nearly as standard a term, though in most places it
is indeed meant to be same as "translation unit", but with the new gcc
inter-module-analysis stuff that you referred to above, I suspect one may
reasonably want to call a "compilation unit" as all that the compiler sees
at a given instant.
BTW I did some auditing (only inside include/asm-{i386,x86_64}/ and
arch/{i386,x86_64}/) and found a couple more callsites that don't use
cpu_relax():
arch/i386/kernel/crash.c:101
arch/x86_64/kernel/crash.c:97
that are:
while ((atomic_read(&waiting_for_crash_ipi) > 0) && msecs) {
mdelay(1);
msecs--;
}
where mdelay() becomes __const_udelay() which happens to be in another
translation unit (arch/i386/lib/delay.c) and hence saves this callsite
from being a bug :-)
Curiously, __const_udelay() is still marked as "inline" where it is
implemented in lib/delay.c which is weird, considering it won't ever
be inlined, would it? With the kernel presently being compiled one
translation unit at a time, I don't see how the implementation would
be visible to any callsite out there to be able to inline it.
Satyam
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