diff --git a/mmtk/Cargo.lock b/mmtk/Cargo.lock
index bd17b57c..eea41fc3 100644
--- a/mmtk/Cargo.lock
+++ b/mmtk/Cargo.lock
@@ -197,9 +197,9 @@ checksum = "a26ae43d7bcc3b814de94796a5e736d4029efb0ee900c12e2d54c993ad1a1e07"
 
 [[package]]
 name = "enum-map"
-version = "2.6.3"
+version = "2.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c188012f8542dee7b3996e44dd89461d64aa471b0a7c71a1ae2f595d259e96e5"
+checksum = "53337c2dbf26a3c31eccc73a37b10c1614e8d4ae99b6a50d553e8936423c1f16"
 dependencies = [
  "enum-map-derive",
 ]
@@ -406,7 +406,7 @@ dependencies = [
 [[package]]
 name = "mmtk"
 version = "0.20.0"
-source = "git+https://github.com/mmtk/mmtk-core.git?rev=06a2e5d9773c9f7a32a6afc1add9cef311432dbc#06a2e5d9773c9f7a32a6afc1add9cef311432dbc"
+source = "git+https://github.com/mmtk/mmtk-core.git?rev=57af17fbfd94ff0df2cd3b1e504abe299ce4f0ab#57af17fbfd94ff0df2cd3b1e504abe299ce4f0ab"
 dependencies = [
  "atomic",
  "atomic-traits",
@@ -440,7 +440,7 @@ dependencies = [
 [[package]]
 name = "mmtk-macros"
 version = "0.20.0"
-source = "git+https://github.com/mmtk/mmtk-core.git?rev=06a2e5d9773c9f7a32a6afc1add9cef311432dbc#06a2e5d9773c9f7a32a6afc1add9cef311432dbc"
+source = "git+https://github.com/mmtk/mmtk-core.git?rev=57af17fbfd94ff0df2cd3b1e504abe299ce4f0ab#57af17fbfd94ff0df2cd3b1e504abe299ce4f0ab"
 dependencies = [
  "proc-macro-error",
  "proc-macro2",
@@ -520,9 +520,9 @@ checksum = "26072860ba924cbfa98ea39c8c19b4dd6a4a25423dbdf219c1eca91aa0cf6964"
 
 [[package]]
 name = "portable-atomic"
-version = "1.4.3"
+version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "31114a898e107c51bb1609ffaf55a0e011cf6a4d7f1170d0015a165082c0338b"
+checksum = "b559898e0b4931ed2d3b959ab0c2da4d99cc644c4b0b1a35b4d344027f474023"
 
 [[package]]
 name = "probe"
@@ -632,9 +632,9 @@ dependencies = [
 
 [[package]]
 name = "rustix"
-version = "0.38.19"
+version = "0.38.20"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "745ecfa778e66b2b63c88a61cb36e0eea109e803b0b86bf9879fbc77c70e86ed"
+checksum = "67ce50cb2e16c2903e30d1cbccfd8387a74b9d4c938b6a4c5ec6cc7556f7a8a0"
 dependencies = [
  "bitflags 2.4.1",
  "errno",
@@ -784,18 +784,18 @@ dependencies = [
 
 [[package]]
 name = "thiserror"
-version = "1.0.49"
+version = "1.0.50"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1177e8c6d7ede7afde3585fd2513e611227efd6481bd78d2e82ba1ce16557ed4"
+checksum = "f9a7210f5c9a7156bb50aa36aed4c95afb51df0df00713949448cf9e97d382d2"
 dependencies = [
  "thiserror-impl",
 ]
 
 [[package]]
 name = "thiserror-impl"
-version = "1.0.49"
+version = "1.0.50"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "10712f02019e9288794769fba95cd6847df9874d49d871d062172f9dd41bc4cc"
+checksum = "266b2e40bc00e5a6c09c3584011e08b06f123c00362c92b975ba9843aaaa14b8"
 dependencies = [
  "proc-macro2",
  "quote",
diff --git a/mmtk/Cargo.toml b/mmtk/Cargo.toml
index 0558103f..f752ad00 100644
--- a/mmtk/Cargo.toml
+++ b/mmtk/Cargo.toml
@@ -32,7 +32,7 @@ memoffset = "0.9.0"
 # - change branch
 # - change repo name
 # But other changes including adding/removing whitespaces in commented lines may break the CI.
-mmtk = { git = "https://github.com/mmtk/mmtk-core.git", rev = "06a2e5d9773c9f7a32a6afc1add9cef311432dbc" }
+mmtk = { git = "https://github.com/mmtk/mmtk-core.git", rev = "57af17fbfd94ff0df2cd3b1e504abe299ce4f0ab" }
 # Uncomment the following to build locally
 # mmtk = { path = "../repos/mmtk-core" }
 
diff --git a/mmtk/src/active_plan.rs b/mmtk/src/active_plan.rs
index 3b3f3c69..72022ffc 100644
--- a/mmtk/src/active_plan.rs
+++ b/mmtk/src/active_plan.rs
@@ -4,7 +4,6 @@ use crate::UPCALLS;
 use mmtk::util::opaque_pointer::*;
 use mmtk::vm::ActivePlan;
 use mmtk::Mutator;
-use mmtk::Plan;
 use std::collections::VecDeque;
 use std::marker::PhantomData;
 
@@ -39,10 +38,6 @@ impl<'a, const COMPRESSED: bool> Iterator for OpenJDKMutatorIterator<'a, COMPRES
 pub struct VMActivePlan {}
 
 impl<const COMPRESSED: bool> ActivePlan<OpenJDK<COMPRESSED>> for VMActivePlan {
-    fn global() -> &'static dyn Plan<VM = OpenJDK<COMPRESSED>> {
-        crate::singleton::<COMPRESSED>().get_plan()
-    }
-
     fn is_mutator(tls: VMThread) -> bool {
         unsafe { ((*UPCALLS).is_mutator)(tls) }
     }
diff --git a/mmtk/src/api.rs b/mmtk/src/api.rs
index 295b4353..10359f5f 100644
--- a/mmtk/src/api.rs
+++ b/mmtk/src/api.rs
@@ -299,11 +299,6 @@ pub extern "C" fn is_mapped_address(addr: Address) -> bool {
     memory_manager::is_mapped_address(addr)
 }
 
-#[no_mangle]
-pub extern "C" fn modify_check(object: ObjectReference) {
-    with_singleton!(|singleton| memory_manager::modify_check(singleton, object))
-}
-
 #[no_mangle]
 pub extern "C" fn add_weak_candidate(reff: ObjectReference) {
     with_singleton!(|singleton| memory_manager::add_weak_candidate(singleton, reff))
diff --git a/openjdk/mmtk.h b/openjdk/mmtk.h
index f78452e2..1298ee51 100644
--- a/openjdk/mmtk.h
+++ b/openjdk/mmtk.h
@@ -68,7 +68,6 @@ extern void release_buffer(void** buffer, size_t len, size_t cap);
 
 extern bool is_in_mmtk_spaces(void* ref);
 extern bool is_mapped_address(void* addr);
-extern void modify_check(void* ref);
 
 // This type declaration needs to match AllocatorSelector in mmtk-core
 struct AllocatorSelector {
diff --git a/openjdk/mmtkMutator.hpp b/openjdk/mmtkMutator.hpp
index 3abb51f7..5498df9c 100644
--- a/openjdk/mmtkMutator.hpp
+++ b/openjdk/mmtkMutator.hpp
@@ -33,13 +33,13 @@ struct BumpAllocator {
   void* cursor;
   void* limit;
   RustDynPtr space;
-  RustDynPtr plan;
+  void* context;
 };
 
 struct LargeObjectAllocator {
   void* tls;
   void* space;
-  RustDynPtr plan;
+  void* context;
 };
 
 struct ImmixAllocator {
@@ -47,7 +47,7 @@ struct ImmixAllocator {
   void* cursor;
   void* limit;
   void* immix_space;
-  RustDynPtr plan;
+  void* context;
   uint8_t hot;
   uint8_t copy;
   void* large_cursor;
@@ -72,7 +72,7 @@ struct FLBlockList {
 struct FreeListAllocator {
   void* tls;
   void* space;
-  RustDynPtr plan;
+  void* context;
   FLBlockList* available_blocks;
   FLBlockList* available_blocks_stress;
   FLBlockList* unswept_blocks;
@@ -82,7 +82,7 @@ struct FreeListAllocator {
 struct MallocAllocator {
   void* tls;
   void* space;
-  RustDynPtr plan;
+  void* context;
 };
 
 struct MarkCompactAllocator {