feat(mimalloc): add mimalloc as global allocator

This is necessary to reduce memory-fragmentation and overalll ram usage in long running deployments

Author: feliwir

CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- Optional `mimalloc` feature that uses mimalloc as the global allocator. Enabled by default in the Docker images to reduce memory growth in long-running deployments (#68)
+
 ### Fixed
 
 ### Changed

Cargo.lock

@@ -17,6 +17,8 @@ readme = "README.md"
 [features]
 default = []
 s3 = ["dep:aws-config", "dep:aws-sdk-s3", "dep:aws-credential-types"]
+# Use mimalloc as the global allocator (reduces memory fragmentation in long-running deployments)
+mimalloc = ["dep:mimalloc"]
 
 [dependencies]
 # DICOM processing
@@ -53,6 +55,7 @@ multer = "3.1.0"
 pin-project = "1.1.10"
 image = { version = "0.25.8", features = ["png", "jpeg", "gif"] }
 http-body-util = "0.1.3"
+mimalloc = { version = "0.1", optional = true }
 
 # S3 backend
 aws-config = { version = "1.8.14", features = ["behavior-version-latest"], optional = true }

Cargo.toml

@@ -8,10 +8,10 @@ RUN cargo chef prepare --recipe-path recipe.json
 FROM chef AS builder
 COPY --from=planner /app/recipe.json recipe.json
 
-RUN cargo chef cook --release --recipe-path recipe.json
+RUN cargo chef cook --release --features mimalloc --recipe-path recipe.json
 
 COPY . .
-RUN cargo build --release --bin dicom-rst
+RUN cargo build --release --features mimalloc --bin dicom-rst
 
 FROM gcr.io/distroless/cc-debian12 AS runtime
 COPY --from=builder /app/target/release/dicom-rst /

Dockerfile

@@ -5,7 +5,7 @@ WORKDIR /app
 
 COPY . .
 
-RUN cargo build --release --locked --features s3 --bin dicom-rst
+RUN cargo build --release --locked --features s3,mimalloc --bin dicom-rst
 
 FROM gcr.io/distroless/cc-debian12 AS runtime
 COPY --from=builder /app/target/release/dicom-rst /

Dockerfile-s3

@@ -31,6 +31,10 @@ use tracing_subscriber::layer::SubscriberExt;
 use tracing_subscriber::util::SubscriberInitExt;
 use tracing_subscriber::EnvFilter;
 
+#[cfg(feature = "mimalloc")]
+#[global_allocator]
+static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;
+
 /// The implementation class UID for DICOM-RST.
 /// The UID is a randomly generated UUID represented as a single integer value under the 2.25 root.
 pub const IMPLEMENTATION_CLASS_UID: &str = "2.25.94508551356620097453554517680708411706";