code review 12418043: net: add special netFD mutex

src/pkg/runtime/mgc0.c

 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 // Garbage collector.
 
 #include "runtime.h"
 #include "arch_GOARCH.h"
 #include "malloc.h"
 #include "stack.h"
@@ skipping 2001 matching lines @@
 
         if(gcpercent == GcpercentUnknown) {     // first time through
                 runtime·lock(&runtime·mheap);
                 if(gcpercent == GcpercentUnknown)
                         gcpercent = readgogc();
                 runtime·unlock(&runtime·mheap);
         }
         if(gcpercent < 0)
                 return;
 
-        runtime·semacquire(&runtime·worldsema);
+        runtime·semacquire(&runtime·worldsema, false);
         if(!force && mstats.heap_alloc < mstats.next_gc) {
                 // typically threads which lost the race to grab
                 // worldsema exit here when gc is done.
                 runtime·semrelease(&runtime·worldsema);
                 return;
         }
 
         // Ok, we're doing it!  Stop everybody else
         a.start_time = runtime·nanotime();
         m->gcing = 1;
@@ skipping 178 matching lines @@
         runtime·MProf_GC();
 }
 
 void
 runtime·ReadMemStats(MStats *stats)
 {
         // Have to acquire worldsema to stop the world,
         // because stoptheworld can only be used by
         // one goroutine at a time, and there might be
         // a pending garbage collection already calling it.
-        runtime·semacquire(&runtime·worldsema);
+        runtime·semacquire(&runtime·worldsema, false);
         m->gcing = 1;
         runtime·stoptheworld();
         updatememstats(nil);
         *stats = mstats;
         m->gcing = 0;
         m->locks++;
         runtime·semrelease(&runtime·worldsema);
         runtime·starttheworld();
         m->locks--;
 }
@@ skipping 306 matching lines @@
         uintptr n;
 
         n = (h->arena_used - h->arena_start) / wordsPerBitmapWord;
         n = ROUND(n, bitmapChunk);
         if(h->bitmap_mapped >= n)
                 return;
 
         runtime·SysMap(h->arena_start - n, n - h->bitmap_mapped);
         h->bitmap_mapped = n;
 }