From: Michael Anthony Knyszek <mknyszek@google.com>
Date: Mon, 12 Apr 2021 22:40:36 +0000 (+0000)
Subject: runtime: track scannable globals space
X-Git-Tag: go1.18beta1~674
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=9da64156a62e4661fb5b0e64a2f196f253ce0dc5;p=gostls13.git

runtime: track scannable globals space

For #44167.

Change-Id: I2cd13229d88f630451fabd113b0e5a04841e9e79
Reviewed-on: https://go-review.googlesource.com/c/go/+/309590
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>
---

diff --git a/src/runtime/mgcpacer.go b/src/runtime/mgcpacer.go
index 9cc7cf99db..ad7c4bb840 100644
--- a/src/runtime/mgcpacer.go
+++ b/src/runtime/mgcpacer.go
@@ -182,6 +182,12 @@ type gcControllerState struct {
 	// Read and updated atomically.
 	scannableStackSize uint64
 
+	// globalsScan is the total amount of global variable space
+	// that is scannable.
+	//
+	// Read and updated atomically.
+	globalsScan uint64
+
 	// heapMarked is the number of bytes marked by the previous
 	// GC. After mark termination, heapLive == heapMarked, but
 	// unlike heapLive, heapMarked does not change until the
@@ -715,6 +721,10 @@ func (c *gcControllerState) addScannableStack(pp *p, amount int64) {
 	}
 }
 
+func (c *gcControllerState) addGlobals(amount int64) {
+	atomic.Xadd64(&c.globalsScan, amount)
+}
+
 // commit sets the trigger ratio and updates everything
 // derived from it: the absolute trigger, the heap goal, mark pacing,
 // and sweep pacing.
diff --git a/src/runtime/symtab.go b/src/runtime/symtab.go
index 41161d6f90..3237a6b708 100644
--- a/src/runtime/symtab.go
+++ b/src/runtime/symtab.go
@@ -529,8 +529,11 @@ func modulesinit() {
 		}
 		*modules = append(*modules, md)
 		if md.gcdatamask == (bitvector{}) {
-			md.gcdatamask = progToPointerMask((*byte)(unsafe.Pointer(md.gcdata)), md.edata-md.data)
-			md.gcbssmask = progToPointerMask((*byte)(unsafe.Pointer(md.gcbss)), md.ebss-md.bss)
+			scanDataSize := md.edata - md.data
+			md.gcdatamask = progToPointerMask((*byte)(unsafe.Pointer(md.gcdata)), scanDataSize)
+			scanBSSSize := md.ebss - md.bss
+			md.gcbssmask = progToPointerMask((*byte)(unsafe.Pointer(md.gcbss)), scanBSSSize)
+			gcController.addGlobals(int64(scanDataSize + scanBSSSize))
 		}
 	}