diff --git a/druntime/src/core/thread/osthread.d b/druntime/src/core/thread/osthread.d
index 5074ccdb7417..827b19b61df9 100644
--- a/druntime/src/core/thread/osthread.d
+++ b/druntime/src/core/thread/osthread.d
@@ -14,7 +14,7 @@ module core.thread.osthread;
 
 import core.atomic;
 import core.internal.traits : externDFunc;
-import core.memory : GC, pageSize;
+import core.memory : GC;
 import core.thread.context;
 import core.thread.threadbase;
 import core.thread.types;
@@ -2220,26 +2220,3 @@ nothrow @nogc unittest
 
     assert(task.n == tids.length);
 }
-
-version (Posix)
-package size_t adjustStackSize(size_t sz) nothrow @nogc
-{
-    if (sz == 0)
-        return 0;
-
-    // stack size must be at least PTHREAD_STACK_MIN for most platforms.
-    if (PTHREAD_STACK_MIN > sz)
-        sz = PTHREAD_STACK_MIN;
-
-    version (CRuntime_Glibc)
-    {
-        // On glibc, TLS uses the top of the stack, so add its size to the requested size
-        sz += externDFunc!("rt.sections_elf_shared.sizeOfTLS",
-                           size_t function() @nogc nothrow)();
-    }
-
-    // stack size must be a multiple of pageSize
-    sz = ((sz + pageSize - 1) & ~(pageSize - 1));
-
-    return sz;
-}
diff --git a/druntime/src/core/thread/posix_impl.d b/druntime/src/core/thread/posix_impl.d
index d1fb6e6b46ad..821ac51e35ba 100644
--- a/druntime/src/core/thread/posix_impl.d
+++ b/druntime/src/core/thread/posix_impl.d
@@ -872,6 +872,31 @@ package bool launchLLThread(LLThreadProperties* tprop, ref LLThreadContext conte
     return true;
 }
 
+private size_t adjustStackSize(size_t sz) nothrow @nogc
+{
+    import core.memory: pageSize;
+    import core.thread.types: PTHREAD_STACK_MIN;
+
+    if (sz == 0)
+        return 0;
+
+    // stack size must be at least PTHREAD_STACK_MIN for most platforms.
+    if (PTHREAD_STACK_MIN > sz)
+        sz = PTHREAD_STACK_MIN;
+
+    version (CRuntime_Glibc)
+    {
+        // On glibc, TLS uses the top of the stack, so add its size to the requested size
+        sz += externDFunc!("rt.sections_elf_shared.sizeOfTLS",
+                           size_t function() @nogc nothrow)();
+    }
+
+    // stack size must be a multiple of pageSize
+    sz = ((sz + pageSize - 1) & ~(pageSize - 1));
+
+    return sz;
+}
+
 version (CoreDdoc) {} else
 void joinLowLevelThread(ThreadID tid) nothrow @nogc
 {