runtime: add sysNoHugePage

Change-Id: Icccafb896de838256a2ec7c3f385e6cbb2b415fa
Reviewed-on: https://go-review.googlesource.com/c/go/+/447360
Auto-Submit: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

7 files changed, 26 insertions, 0 deletions

diff --git a/src/runtime/mem.go b/src/runtime/mem.go
index 0ca933b25b..7b01905224 100644
--- a/src/runtime/mem.go
+++ b/src/runtime/mem.go
@@ -84,6 +84,13 @@ func sysHugePage(v unsafe.Pointer, n uintptr) {
 	sysHugePageOS(v, n)
 }
 
+// sysNoHugePage does not transition memory regions, but instead provides a
+// hint to the OS that it would be less efficient to back this memory region
+// with pages of a larger size transparently.
+func sysNoHugePage(v unsafe.Pointer, n uintptr) {
+	sysNoHugePageOS(v, n)
+}
+
 // sysFree transitions a memory region from any state to None. Therefore, it
 // returns memory unconditionally. It is used if an out-of-memory error has been
 // detected midway through an allocation or to carve out an aligned section of
diff --git a/src/runtime/mem_aix.go b/src/runtime/mem_aix.go
index 21726b56ae..deae61635c 100644
--- a/src/runtime/mem_aix.go
+++ b/src/runtime/mem_aix.go
@@ -38,6 +38,9 @@ func sysUsedOS(v unsafe.Pointer, n uintptr) {
 func sysHugePageOS(v unsafe.Pointer, n uintptr) {
 }
 
+func sysNoHugePageOS(v unsafe.Pointer, n uintptr) {
+}
+
 // Don't split the stack as this function may be invoked without a valid G,
 // which prevents us from allocating more stack.
 //
diff --git a/src/runtime/mem_bsd.go b/src/runtime/mem_bsd.go
index 6c5edb17c2..a9025ad015 100644
--- a/src/runtime/mem_bsd.go
+++ b/src/runtime/mem_bsd.go
@@ -36,6 +36,9 @@ func sysUsedOS(v unsafe.Pointer, n uintptr) {
 func sysHugePageOS(v unsafe.Pointer, n uintptr) {
 }
 
+func sysNoHugePageOS(v unsafe.Pointer, n uintptr) {
+}
+
 // Don't split the stack as this function may be invoked without a valid G,
 // which prevents us from allocating more stack.
 //
diff --git a/src/runtime/mem_darwin.go b/src/runtime/mem_darwin.go
index 25862cf161..1e3e53d45b 100644
--- a/src/runtime/mem_darwin.go
+++ b/src/runtime/mem_darwin.go
@@ -36,6 +36,9 @@ func sysUsedOS(v unsafe.Pointer, n uintptr) {
 func sysHugePageOS(v unsafe.Pointer, n uintptr) {
 }
 
+func sysNoHugePageOS(v unsafe.Pointer, n uintptr) {
+}
+
 // Don't split the stack as this function may be invoked without a valid G,
 // which prevents us from allocating more stack.
 //
diff --git a/src/runtime/mem_linux.go b/src/runtime/mem_linux.go
index 1630664cff..96e890eedb 100644
--- a/src/runtime/mem_linux.go
+++ b/src/runtime/mem_linux.go
@@ -161,6 +161,10 @@ func sysHugePageOS(v unsafe.Pointer, n uintptr) {
 	}
 }
 
+func sysNoHugePageOS(v unsafe.Pointer, n uintptr) {
+	madvise(v, n, _MADV_NOHUGEPAGE)
+}
+
 // Don't split the stack as this function may be invoked without a valid G,
 // which prevents us from allocating more stack.
 //
diff --git a/src/runtime/mem_sbrk.go b/src/runtime/mem_sbrk.go
index 4d5d3d7ce3..c8f50e7bd5 100644
--- a/src/runtime/mem_sbrk.go
+++ b/src/runtime/mem_sbrk.go
@@ -160,6 +160,9 @@ func sysUsedOS(v unsafe.Pointer, n uintptr) {
 func sysHugePageOS(v unsafe.Pointer, n uintptr) {
 }
 
+func sysNoHugePageOS(v unsafe.Pointer, n uintptr) {
+}
+
 func sysMapOS(v unsafe.Pointer, n uintptr) {
 }
 
diff --git a/src/runtime/mem_windows.go b/src/runtime/mem_windows.go
index b1292fc725..c11abc17ad 100644
--- a/src/runtime/mem_windows.go
+++ b/src/runtime/mem_windows.go
@@ -94,6 +94,9 @@ func sysUsedOS(v unsafe.Pointer, n uintptr) {
 func sysHugePageOS(v unsafe.Pointer, n uintptr) {
 }
 
+func sysNoHugePageOS(v unsafe.Pointer, n uintptr) {
+}
+
 // Don't split the stack as this function may be invoked without a valid G,
 // which prevents us from allocating more stack.
 //