Use memmap2 in deserialize_from_file

wasmerio · Dec 14, 2020 · e5a52f1 · e5a52f1
1 parent ae7ec9d
commit e5a52f1
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Showing 4 changed files with 16 additions and 2 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -12,6 +12,7 @@
 * [#1867](https://github.com/wasmerio/wasmer/pull/1867) Added `Metering::get_remaining_points` and `Metering::set_remaining_points` 
 * [#1881](https://github.com/wasmerio/wasmer/pull/1881) Added `UnsupportedTarget` error to `CompileError`
 * [#1908](https://github.com/wasmerio/wasmer/pull/1908) Implemented `TryFrom<Value<T>>` for `i32`/`u32`/`i64`/`u64`/`f32`/`f64`
+* [#1927](https://github.com/wasmerio/wasmer/pull/1927) Added mmap support in `Engine::deserialize_from_file` to speed up artifact loading
 
 ### Changed
 

diff --git a/Cargo.lock b/Cargo.lock
diff --git a/lib/engine/Cargo.toml b/lib/engine/Cargo.toml
@@ -18,6 +18,7 @@ target-lexicon = { version = "0.11", default-features = false }
 # flexbuffers = { path = "../../../flatbuffers/rust/flexbuffers", version = "0.1.0" }
 backtrace = "0.3"
 rustc-demangle = "0.1"
+memmap2 = "0.1.0"
 more-asserts = "0.2"
 thiserror = "1.0"
 serde = { version = "1.0", features = ["derive", "rc"] }

diff --git a/lib/engine/src/engine.rs b/lib/engine/src/engine.rs
@@ -2,6 +2,7 @@
 
 use crate::tunables::Tunables;
 use crate::{Artifact, DeserializeError};
+use memmap2::Mmap;
 use std::path::Path;
 use std::sync::atomic::{AtomicUsize, Ordering::SeqCst};
 use std::sync::Arc;
@@ -51,8 +52,9 @@ pub trait Engine {
         &self,
         file_ref: &Path,
     ) -> Result<Arc<dyn Artifact>, DeserializeError> {
-        let bytes = std::fs::read(file_ref)?;
-        self.deserialize(&bytes)
+        let file = std::fs::File::open(file_ref)?;
+        let mmap = Mmap::map(&file)?;
+        self.deserialize(&mmap)
     }
 
     /// A unique identifier for this object.