diff options
| author | Rick Hudson <rlh@golang.org> | 2015-03-24 11:18:46 -0400 |
|---|---|---|
| committer | Rick Hudson <rlh@golang.org> | 2015-03-24 16:42:39 +0000 |
| commit | 546a54bb2e96f9561e71acf5e70df466056aefaf (patch) | |
| tree | 2c017f7fdae290d1c3f470e51b39692de7df075a /src/runtime | |
| parent | 9b69196958a1ba3eba7a1621894ea9aafaa91648 (diff) | |
| download | go-546a54bb2e96f9561e71acf5e70df466056aefaf.tar.xz | |
runtime: Remove write barrier on g
There are calls to stdcall when the GC thinks the world is stopped
and stdcall write a *g for the CPU profiler. This produces a write
barrier but the GC is not prepared to deal with write barriers when
it thinks the world is stopped. Since the g is on allg it does not
need a write barrier to keep it alive so eliminate the write barrier.
Change-Id: I937633409a66553d7d292d87d7d58caba1fad0b6
Reviewed-on: https://go-review.googlesource.com/7979
Reviewed-by: Austin Clements <austin@google.com>
Run-TryBot: Rick Hudson <rlh@golang.org>
Diffstat (limited to 'src/runtime')
| -rw-r--r-- | src/runtime/os1_windows.go | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/src/runtime/os1_windows.go b/src/runtime/os1_windows.go index 561d3ce457..4ae1a8411b 100644 --- a/src/runtime/os1_windows.go +++ b/src/runtime/os1_windows.go @@ -359,6 +359,8 @@ func nanotime() int64 { } // Calling stdcall on os stack. +// May run during STW, so write barriers are not allowed. +//go:nowritebarrier //go:nosplit func stdcall(fn stdFunction) uintptr { gp := getg() @@ -367,7 +369,8 @@ func stdcall(fn stdFunction) uintptr { if mp.profilehz != 0 { // leave pc/sp for cpu profiler - mp.libcallg = gp + // gp is on allg, so this WB can be eliminated. + setGNoWriteBarrier(&mp.libcallg, gp) mp.libcallpc = getcallerpc(unsafe.Pointer(&fn)) // sp must be the last, because once async cpu profiler finds // all three values to be non-zero, it will use them |