diff --git a/init/README.md b/init/README.md
index 4be521902..6f2c01f05 100644
--- a/init/README.md
+++ b/init/README.md
@@ -623,8 +623,11 @@ provides the `aidl_lazy_test_1` interface.
 `stop <service>`
 > Stop a service from running if it is currently running.
 
-`swapon_all <fstab>`
+`swapon_all [ <fstab> ]`
 > Calls fs\_mgr\_swapon\_all on the given fstab file.
+  If the fstab parameter is not specified, fstab.${ro.boot.fstab_suffix},
+  fstab.${ro.hardware} or fstab.${ro.hardware.platform} will be scanned for
+  under /odm/etc, /vendor/etc, or / at runtime, in that order.
 
 `symlink <target> <path>`
 > Create a symbolic link at _path_ with the value _target_
diff --git a/init/builtins.cpp b/init/builtins.cpp
index e918e12ae..0ac66f272 100644
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -708,10 +708,20 @@ static Result<void> do_umount_all(const BuiltinArguments& args) {
     return {};
 }
 
+/* swapon_all [ <fstab> ] */
 static Result<void> do_swapon_all(const BuiltinArguments& args) {
+    auto swapon_all = ParseSwaponAll(args.args);
+    if (!swapon_all.ok()) return swapon_all.error();
+
     Fstab fstab;
-    if (!ReadFstabFromFile(args[1], &fstab)) {
-        return Error() << "Could not read fstab '" << args[1] << "'";
+    if (swapon_all->empty()) {
+        if (!ReadDefaultFstab(&fstab)) {
+            return Error() << "Could not read default fstab";
+        }
+    } else {
+        if (!ReadFstabFromFile(*swapon_all, &fstab)) {
+            return Error() << "Could not read fstab '" << *swapon_all << "'";
+        }
     }
 
     if (!fs_mgr_swapon_all(fstab)) {
@@ -1371,7 +1381,7 @@ const BuiltinFunctionMap& GetBuiltinFunctionMap() {
         {"setrlimit",               {3,     3,    {false,  do_setrlimit}}},
         {"start",                   {1,     1,    {false,  do_start}}},
         {"stop",                    {1,     1,    {false,  do_stop}}},
-        {"swapon_all",              {1,     1,    {false,  do_swapon_all}}},
+        {"swapon_all",              {0,     1,    {false,  do_swapon_all}}},
         {"enter_default_mount_ns",  {0,     0,    {false,  do_enter_default_mount_ns}}},
         {"symlink",                 {2,     2,    {true,   do_symlink}}},
         {"sysclktz",                {1,     1,    {false,  do_sysclktz}}},
diff --git a/init/check_builtins.cpp b/init/check_builtins.cpp
index 450c079a8..481fa31e5 100644
--- a/init/check_builtins.cpp
+++ b/init/check_builtins.cpp
@@ -202,6 +202,14 @@ Result<void> check_setrlimit(const BuiltinArguments& args) {
     return {};
 }
 
+Result<void> check_swapon_all(const BuiltinArguments& args) {
+    auto options = ParseSwaponAll(args.args);
+    if (!options.ok()) {
+        return options.error();
+    }
+    return {};
+}
+
 Result<void> check_sysclktz(const BuiltinArguments& args) {
     ReturnIfAnyArgsEmpty();
 
diff --git a/init/check_builtins.h b/init/check_builtins.h
index 725a6fd65..dc1b752e7 100644
--- a/init/check_builtins.h
+++ b/init/check_builtins.h
@@ -37,6 +37,7 @@ Result<void> check_restorecon(const BuiltinArguments& args);
 Result<void> check_restorecon_recursive(const BuiltinArguments& args);
 Result<void> check_setprop(const BuiltinArguments& args);
 Result<void> check_setrlimit(const BuiltinArguments& args);
+Result<void> check_swapon_all(const BuiltinArguments& args);
 Result<void> check_sysclktz(const BuiltinArguments& args);
 Result<void> check_umount_all(const BuiltinArguments& args);
 Result<void> check_wait(const BuiltinArguments& args);
diff --git a/init/util.cpp b/init/util.cpp
index 90ac50cd1..255434a1b 100644
--- a/init/util.cpp
+++ b/init/util.cpp
@@ -652,11 +652,22 @@ Result<std::pair<int, std::vector<std::string>>> ParseRestorecon(
     return std::pair(flag, paths);
 }
 
+Result<std::string> ParseSwaponAll(const std::vector<std::string>& args) {
+    if (args.size() <= 1) {
+        if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) {
+            return Error() << "swapon_all requires at least 1 argument";
+        }
+        return {};
+    }
+    return args[1];
+}
+
 Result<std::string> ParseUmountAll(const std::vector<std::string>& args) {
-    if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) {
-        if (args.size() <= 1) {
+    if (args.size() <= 1) {
+        if (SelinuxGetVendorAndroidVersion() <= __ANDROID_API_Q__) {
             return Error() << "umount_all requires at least 1 argument";
         }
+        return {};
     }
     return args[1];
 }
diff --git a/init/util.h b/init/util.h
index a7f813b53..3cdc9f408 100644
--- a/init/util.h
+++ b/init/util.h
@@ -92,6 +92,8 @@ Result<MountAllOptions> ParseMountAll(const std::vector<std::string>& args);
 Result<std::pair<int, std::vector<std::string>>> ParseRestorecon(
         const std::vector<std::string>& args);
 
+Result<std::string> ParseSwaponAll(const std::vector<std::string>& args);
+
 Result<std::string> ParseUmountAll(const std::vector<std::string>& args);
 
 void SetStdioToDevNull(char** argv);