From 9085261a85e1020a2003a283a4f45fbd804d4dab Mon Sep 17 00:00:00 2001
From: Stephan Vedder <stephan.vedder@gmail.com>
Date: Mon, 21 Sep 2026 06:55:24 +0200
Subject: [PATCH] feat(mimalloc): add mimalloc as global allocator

This is necessary to reduce memory-fragmentation and overalll ram usage in long running deployments
---
 CHANGELOG.md  |  2 ++
 Cargo.lock    | 19 +++++++++++++++++++
 Cargo.toml    |  3 +++
 Dockerfile    |  4 ++--
 Dockerfile-s3 |  2 +-
 src/main.rs   |  4 ++++
 6 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 84e52ef..b9365d0 100644
--- a/CHANGELOG.md
+++ b/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
diff --git a/Cargo.lock b/Cargo.lock
index af6d549..a0db6fc 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1720,6 +1720,7 @@ dependencies = [
  "futures",
  "http-body-util",
  "image",
+ "mimalloc",
  "mime",
  "multer",
  "pin-project",
@@ -3379,6 +3380,15 @@ dependencies = [
  "cc",
 ]
 
+[[package]]
+name = "libmimalloc-sys"
+version = "0.1.49"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a45a52f43e1c16f667ccfe4dd8c85b7f7c204fd5e3bf46c5b0db9a5c3c0b8e9"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "linux-raw-sys"
 version = "0.11.0"
@@ -3500,6 +3510,15 @@ version = "2.8.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf8baf1c55e62ffcace7a9f06f4bd9cd3f0c4beb022d3b367256b91b87513d98"
 
+[[package]]
+name = "mimalloc"
+version = "0.1.52"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2d4139bb28d14ad1facf21d5eb8825051b326e172d216b39f6d31df53cc97862"
+dependencies = [
+ "libmimalloc-sys",
+]
+
 [[package]]
 name = "mime"
 version = "0.3.17"
diff --git a/Cargo.toml b/Cargo.toml
index 814dc4b..635c746 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -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 }
diff --git a/Dockerfile b/Dockerfile
index b3f015c..63f7ac4 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -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 /
diff --git a/Dockerfile-s3 b/Dockerfile-s3
index a793b32..bb1f4f5 100644
--- a/Dockerfile-s3
+++ b/Dockerfile-s3
@@ -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 /
diff --git a/src/main.rs b/src/main.rs
index 6c23b68..5d9b0cc 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -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";