runtime: move internal GC statistics from memstats to gcController

This change moves certain important but internal-only GC statistics from
memstats into gcController. These statistics are mainly used in pacing
the GC, so it makes sense to keep them in the pacer's state.

This CL was mostly generated via

rf '
    ex . {
	memstats.gc_trigger -> gcController.trigger
	memstats.triggerRatio -> gcController.triggerRatio
	memstats.heap_marked -> gcController.heapMarked
	memstats.heap_live -> gcController.heapLive
	memstats.heap_scan -> gcController.heapScan
    }
'

except for a few special cases, like updating names in comments and when
these fields are used within gcControllerState methods (at which point
they're accessed through the reciever).

For #44167.

Change-Id: I6bd1602585aeeb80818ded24c07d8e6fec992b93
Reviewed-on: https://go-review.googlesource.com/c/go/+/306598
Trust: Michael Knyszek <mknyszek@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Michael Pratt <mpratt@google.com>

1 files changed, 17 insertions, 17 deletions

diff --git a/src/runtime/mgc.go b/src/runtime/mgc.go
index 8831e27554..ff0618a053 100644
--- a/src/runtime/mgc.go
+++ b/src/runtime/mgc.go
@@ -158,12 +158,12 @@ func gcinit() {
 	mheap_.sweepDrained = 1
 
 	// Set a reasonable initial GC trigger.
-	memstats.triggerRatio = 7 / 8.0
+	gcController.triggerRatio = 7 / 8.0
 
-	// Fake a heap_marked value so it looks like a trigger at
-	// heapMinimum is the appropriate growth from heap_marked.
+	// Fake a heapMarked value so it looks like a trigger at
+	// heapMinimum is the appropriate growth from heapMarked.
 	// This will go into computing the initial GC goal.
-	memstats.heap_marked = uint64(float64(heapMinimum) / (1 + memstats.triggerRatio))
+	gcController.heapMarked = uint64(float64(heapMinimum) / (1 + gcController.triggerRatio))
 
 	// Set gcPercent from the environment. This will also compute
 	// and set the GC trigger and goal.
@@ -370,7 +370,7 @@ var work struct {
 	// program started if debug.gctrace > 0.
 	totaltime int64
 
-	// initialHeapLive is the value of memstats.heap_live at the
+	// initialHeapLive is the value of gcController.heapLive at the
 	// beginning of this GC cycle.
 	initialHeapLive uint64
 
@@ -551,11 +551,11 @@ func (t gcTrigger) test() bool {
 	}
 	switch t.kind {
 	case gcTriggerHeap:
-		// Non-atomic access to heap_live for performance. If
+		// Non-atomic access to gcController.heapLive for performance. If
 		// we are going to trigger on this, this thread just
-		// atomically wrote heap_live anyway and we'll see our
+		// atomically wrote gcController.heapLive anyway and we'll see our
 		// own write.
-		return memstats.heap_live >= memstats.gc_trigger
+		return gcController.heapLive >= gcController.trigger
 	case gcTriggerTime:
 		if gcPercent < 0 {
 			return false
@@ -651,7 +651,7 @@ func gcStart(trigger gcTrigger) {
 		// so it can't be more than ncpu, even if GOMAXPROCS is.
 		work.stwprocs = ncpu
 	}
-	work.heap0 = atomic.Load64(&memstats.heap_live)
+	work.heap0 = atomic.Load64(&gcController.heapLive)
 	work.pauseNS = 0
 	work.mode = mode
 
@@ -915,7 +915,7 @@ func gcMarkTermination(nextTriggerRatio float64) {
 	// Start marktermination (write barrier remains enabled for now).
 	setGCPhase(_GCmarktermination)
 
-	work.heap1 = memstats.heap_live
+	work.heap1 = gcController.heapLive
 	startTime := nanotime()
 
 	mp := acquirem()
@@ -1432,25 +1432,25 @@ func gcMark(start_time int64) {
 	}
 
 	// Update the marked heap stat.
-	memstats.heap_marked = work.bytesMarked
+	gcController.heapMarked = work.bytesMarked
 
 	// Flush scanAlloc from each mcache since we're about to modify
-	// heap_scan directly. If we were to flush this later, then scanAlloc
+	// heapScan directly. If we were to flush this later, then scanAlloc
 	// might have incorrect information.
 	for _, p := range allp {
 		c := p.mcache
 		if c == nil {
 			continue
 		}
-		memstats.heap_scan += uint64(c.scanAlloc)
+		gcController.heapScan += uint64(c.scanAlloc)
 		c.scanAlloc = 0
 	}
 
 	// Update other GC heap size stats. This must happen after
 	// cachestats (which flushes local statistics to these) and
-	// flushallmcaches (which modifies heap_live).
-	memstats.heap_live = work.bytesMarked
-	memstats.heap_scan = uint64(gcController.scanWork)
+	// flushallmcaches (which modifies gcController.heapLive).
+	gcController.heapLive = work.bytesMarked
+	gcController.heapScan = uint64(gcController.scanWork)
 
 	if trace.enabled {
 		traceHeapAlloc()
@@ -1543,7 +1543,7 @@ func gcResetMarkState() {
 	}
 
 	work.bytesMarked = 0
-	work.initialHeapLive = atomic.Load64(&memstats.heap_live)
+	work.initialHeapLive = atomic.Load64(&gcController.heapLive)
 }
 
 // Hooks for other packages