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| author | Dmitriy Vyukov <dvyukov@google.com> | 2014-08-25 20:26:32 +0400 |
|---|---|---|
| committer | Dmitriy Vyukov <dvyukov@google.com> | 2014-08-25 20:26:32 +0400 |
| commit | 4064d5e9a3dce1b88866f1364a94a02f13db6162 (patch) | |
| tree | 33339f5249e5f8c874c6276f8196c03227fefff7 /src/pkg | |
| parent | 9601abaf8b3d454f6bf84ba9f5e07c11de16ef14 (diff) | |
| download | go-4064d5e9a3dce1b88866f1364a94a02f13db6162.tar.xz | |
runtime: add comment
Explain why it's safe to allocate chans with flagNoScan.
LGTM=rsc
R=golang-codereviews
CC=golang-codereviews, khr, rsc
https://golang.org/cl/125510045
Diffstat (limited to 'src/pkg')
| -rw-r--r-- | src/pkg/runtime/chan.go | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/src/pkg/runtime/chan.go b/src/pkg/runtime/chan.go index bbf5e7aa83..d3fcc6d13f 100644 --- a/src/pkg/runtime/chan.go +++ b/src/pkg/runtime/chan.go @@ -33,7 +33,11 @@ func makechan(t *chantype, size int64) *hchan { var c *hchan if elem.kind&kindNoPointers != 0 || size == 0 { - // allocate memory in one call + // Allocate memory in one call. + // Hchan does not contain pointers interesting for GC in this case: + // buf points into the same allocation, elemtype is persistent + // and SudoG's are referenced from G so can't be collected. + // TODO(dvyukov,rlh): Rethink when collector can move allocated objects. c = (*hchan)(gomallocgc(hchanSize+uintptr(size)*uintptr(elem.size), nil, flagNoScan)) if size > 0 && elem.size != 0 { c.buf = (*uint8)(add(unsafe.Pointer(c), hchanSize)) |