diff options
Diffstat (limited to 'src/runtime/mgcwork.go')
| -rw-r--r-- | src/runtime/mgcwork.go | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/src/runtime/mgcwork.go b/src/runtime/mgcwork.go index 1df40d2afe..a9559230de 100644 --- a/src/runtime/mgcwork.go +++ b/src/runtime/mgcwork.go @@ -12,8 +12,22 @@ import ( const ( _WorkbufSize = 2048 // in bytes; larger values result in less contention + + // workbufAlloc is the number of bytes to allocate at a time + // for new workbufs. This must be a multiple of pageSize and + // should be a multiple of _WorkbufSize. + // + // Larger values reduce workbuf allocation overhead. Smaller + // values reduce heap fragmentation. + workbufAlloc = 32 << 10 ) +func init() { + if workbufAlloc%pageSize != 0 || workbufAlloc%_WorkbufSize != 0 { + throw("bad workbufAlloc") + } +} + // Garbage collector work pool abstraction. // // This implements a producer/consumer model for pointers to grey @@ -318,7 +332,29 @@ func getempty() *workbuf { } } if b == nil { - b = (*workbuf)(persistentalloc(unsafe.Sizeof(*b), sys.CacheLineSize, &memstats.gc_sys)) + // Allocate more workbufs. + var s *mspan + systemstack(func() { + s = mheap_.allocManual(workbufAlloc/pageSize, &memstats.gc_sys) + }) + if s == nil { + throw("out of memory") + } + // Record the new span in the busy list. + lock(&work.wbufSpans.lock) + work.wbufSpans.busy.insert(s) + unlock(&work.wbufSpans.lock) + // Slice up the span into new workbufs. Return one and + // put the rest on the empty list. + for i := uintptr(0); i+_WorkbufSize <= workbufAlloc; i += _WorkbufSize { + newb := (*workbuf)(unsafe.Pointer(s.base() + i)) + newb.nobj = 0 + if i == 0 { + b = newb + } else { + putempty(newb) + } + } } return b } |