UMTX_OP_WAIT expects that the address points to a uintptr, but
the code in lock_futex.c uses a uint32. UMTX_OP_WAIT_UINT is
just like UMTX_OP_WAIT, but the address points to a uint32.
This almost certainly makes no difference on a little-endian
system, but since the kernel supports it we should do the
right thing. And, who knows, maybe it matters.
R=golang-dev, bradfitz, r, ality
CC=golang-dev
https://golang.org/cl/8699043
madvise was missing so implement it in assembler. This change
needs to be extended to the other BSD variantes (Net and Open)
Without this change the scavenger will attempt to pass memory back
to the operating system when it has become idle, but the memory is
not returned and for long running Go processes the total memory used
can grow until OOM occurs.
I have only been able to test the code on FreeBSD AMD64. The ARM
platforms needs testing.
R=golang-dev, mikioh.mikioh, dave, jgc, minux.ma
CC=golang-dev
https://golang.org/cl/6850081
Ian Lance Taylor
Mikio Hara
John Graham-Cumming
Shenghou Ma