runtime: make "write barriers are not allowed" comments more precise
Currently, various functions are marked with the comment
// May run without a P, so write barriers are not allowed.
However, "running without a P" is ambiguous. We intended these to mean
that m.p may be nil (which is the condition checked by the write
barrier). The comment could also be taken to mean that a
stop-the-world may happen, which is not the case for these functions
because they run in situations where there is in fact a function on
the stack holding a P locally, it just isn't in m.p.
Change these comments to state precisely what we mean, that m.p may be
nil.
Change-Id: I4a4a1d26aebd455e5067540e13b9f96a7482146c
Reviewed-on: https://go-review.googlesource.com/8209
Reviewed-by: Minux Ma <minux@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>
diff --git a/src/runtime/os1_darwin.go b/src/runtime/os1_darwin.go
index f6eb557..6c79bbb 100644
--- a/src/runtime/os1_darwin.go
+++ b/src/runtime/os1_darwin.go
@@ -71,7 +71,7 @@
}
}
-// May run without a P, so write barriers are not allowed.
+// May run with m.p==nil, so write barriers are not allowed.
//go:nowritebarrier
func newosproc(mp *m, stk unsafe.Pointer) {
mp.tls[0] = uintptr(mp.id) // so 386 asm can find it
