Merge pull request #1972 from radixdlt/feature/decrease-buffer-limit

Decrease max number of buffers

radix-common/src/constants/transaction_execution.rs

@@ -124,6 +124,3 @@ pub const USD_PRICE_IN_XRD: &str = "16.666666666666666666";
 
 /// The maximum that a package or component owner is allowed to set their method royalty to. 10 USD
 pub const MAX_PER_FUNCTION_ROYALTY_IN_XRD: &str = "166.666666666666666666";
-
-/// The maximum number of "live" buffers maintained by Scrypto runtime.
-pub const MAX_NUMBER_OF_BUFFERS: usize = 32;

radix-engine-tests/assets/blueprints/Cargo.toml

@@ -80,6 +80,7 @@ members = [
     "oracles/oracle_v3",
     "steal",
     "locker-factory",
+    "wasm_limits",
 ]
 resolver = "2"
 

radix-engine-tests/assets/blueprints/wasm_limits/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "wasm_limits"
+version = "1.0.0"
+edition = "2021"
+
+[dependencies]
+scrypto = { path = "../../../../scrypto" }
+
+[lib]
+crate-type = ["cdylib", "lib"]

radix-engine-tests/assets/blueprints/wasm_limits/src/lib.rs

@@ -0,0 +1,14 @@
+use scrypto::prelude::*;
+
+#[blueprint]
+mod wasm_limits {
+    struct WasmLimits {}
+
+    impl WasmLimits {
+        pub fn create_buffers(n: usize) {
+            for _ in 0..n {
+                let _ = unsafe { wasm_api::actor::actor_get_blueprint_name() };
+            }
+        }
+    }
+}

radix-engine-tests/tests/vm/mod.rs

@@ -14,6 +14,7 @@ mod scrypto_validation;
 mod scrypto_validator;
 mod stack_size;
 mod system_wasm_buffers;
+mod wasm_limits;
 mod wasm_memory;
 mod wasm_metering;
 mod wasm_non_mvp;

radix-engine-tests/tests/vm/wasm_limits.rs

@@ -0,0 +1,43 @@
+use radix_engine_tests::common::PackageLoader;
+use scrypto_test::prelude::*;
+
+#[test]
+fn test_create_buffers_within_limits() {
+    // Arrange
+    let mut ledger = LedgerSimulatorBuilder::new().build();
+    let package = ledger.publish_package_simple(PackageLoader::get("wasm_limits"));
+
+    let manifest = ManifestBuilder::new()
+        .lock_fee_from_faucet()
+        .call_function(package, "WasmLimits", "create_buffers", (4usize,))
+        .build();
+
+    // Act
+    let receipt = ledger.execute_manifest(manifest, vec![]);
+
+    // Assert
+    receipt.expect_commit_success();
+}
+
+#[test]
+fn test_crate_buffers_beyond_limits() {
+    // Arrange
+    let mut ledger = LedgerSimulatorBuilder::new().build();
+    let package = ledger.publish_package_simple(PackageLoader::get("wasm_limits"));
+
+    let manifest = ManifestBuilder::new()
+        .lock_fee_from_faucet()
+        .call_function(package, "WasmLimits", "create_buffers", (5usize,))
+        .build();
+
+    // Act
+    let receipt = ledger.execute_manifest(manifest, vec![]);
+
+    // Assert
+    receipt.expect_specific_failure(|runtime_error| {
+        matches!(
+            runtime_error,
+            RuntimeError::VmError(VmError::Wasm(WasmRuntimeError::TooManyBuffers))
+        )
+    })
+}

radix-engine/src/vm/wasm_runtime/scrypto_runtime.rs

@@ -20,7 +20,6 @@ pub struct ScryptoRuntime<'y, Y: SystemApi<RuntimeError>> {
     package_address: PackageAddress,
     export_name: String,
     wasm_execution_units_buffer: u32,
-    max_number_of_buffers: usize,
     scrypto_vm_version: ScryptoVmVersion,
 }
 
@@ -38,7 +37,6 @@ impl<'y, Y: SystemApi<RuntimeError>> ScryptoRuntime<'y, Y> {
             package_address,
             export_name,
             wasm_execution_units_buffer: 0,
-            max_number_of_buffers: MAX_NUMBER_OF_BUFFERS,
             scrypto_vm_version,
         }
     }
@@ -83,7 +81,14 @@ impl<'y, Y: SystemApi<RuntimeError>> WasmRuntime for ScryptoRuntime<'y, Y> {
     ) -> Result<Buffer, InvokeError<WasmRuntimeError>> {
         assert!(buffer.len() <= 0xffffffff);
 
-        if self.buffers.len() >= self.max_number_of_buffers {
+        let max_number_of_buffers = match self.scrypto_vm_version {
+            ScryptoVmVersion::V1_0 | ScryptoVmVersion::V1_1 => 32,
+            // Practically speaking, there is little gain of keeping multiple buffers open before
+            // [multi-value](https://github.com/WebAssembly/multi-value/blob/master/proposals/multi-value/Overview.md) is supported and used.
+            // We reduce it to `4` so that the amount of memory that a transaction can consume is reduced, which is beneficial for parallel execution.
+            ScryptoVmVersion::V1_2 => 4,
+        };
+        if self.buffers.len() >= max_number_of_buffers {
             return Err(InvokeError::SelfError(WasmRuntimeError::TooManyBuffers));
         }