Changes in malloc.rs

b8f882d1 - Add support for fine-grained operator costs (#11572) (#12541)

Thu, 19 Feb 2026 19:37:54 +0000

Add support for fine-grained operator costs (#11572) (#12541)Introduce `OperatorCostStrategy` and `OperatorCost` to allow configuringper-operator fuel costs via `Config::operator_cost`. Previously, operatorcosts were hardcoded inline in both Cranelift and Winch code generation.Now the cost logic is centralized in `wasmtime-environ` and referencedfrom both backends via `tunables.operator_cost.cost(op)`.`OperatorCostStrategy` is an enum with two variants:- `Default`: reproduces the original hardcoded behavior (nop/drop/control flow cost 0, everything else costs 1).- `Table(Box)`: a per-operator cost table generated via `wasmparser::for_each_operator!`.Because `OperatorCostStrategy::Table` contains a `Box`, the type has adestructor. This makes `Tunables` non-trivially droppable, which preventsusing the `..Tunables::default_miri()` functional update syntax in constfunctions (E0493). To work around this, `default_miri`, `default_u32`,and `default_u64` are changed to non-const fns. None ofthese are called in const contexts, except in tests. List of files: /wasmtime-44.0.1/crates/wasmtime/src/runtime/vm/memory/malloc.rs

c656ed3b - Add context to malloc-based-memory error messages (#12468)

Thu, 29 Jan 2026 19:09:48 +0000

Add context to malloc-based-memory error messages (#12468)Add in byte counts with more rationale on where the numbers are comingfrom.Closes #12445 List of files: /wasmtime-44.0.1/crates/wasmtime/src/runtime/vm/memory/malloc.rs

046a51ca - Avoid cloning and dropping `Arc`s in `LocalMemory::vmmemory` (#11148)

Fri, 27 Jun 2025 18:51:03 +0000

Avoid cloning and dropping `Arc`s in `LocalMemory::vmmemory` (#11148)* Avoid cloning and dropping `Arc`s in `LocalMemory::vmmemory`Getting the base pointer from the underlying `dyn RuntimeLinearMemory` involvedgetting a `MemoryBase` which is potentially an `MmapOffset` which itselfcontains an `Arc`, and we would then call `base.as_non_null()` to turnthis into a raw pointer, and then we would drop the `MemoryBase` whichultimately drops the `Arc`. So that's an `Arc` clone and drop just to geta `VMMemoryDefinition`, which is just a pointer and a length, essentially aslice of the linear memory. And, among other places, we call`LocalMemory::vmmemory` to get the GC heap's memory base and bound every time weaccess a GC object from Rust (for example, during collections).Altogether, this removes another 30% of runtime from the testcase inhttps://github.com/bytecodealliance/wasmtime/issues/11141* Construct `VMMemoryDefinition`s in the `RuntimeLinearMemory` implementationInstead of in `LocalMemory` via calling various `RuntimeLinearMemory` methods,as `LocalMemory` has a `dyn RuntimeLinearMemory` object so those calls are allindirect. List of files: /wasmtime-44.0.1/crates/wasmtime/src/runtime/vm/memory/malloc.rs

90ac295e - Update Wasmtime to the 2024 Rust Edition (#10806)

Mon, 19 May 2025 16:40:55 +0000

Update Wasmtime to the 2024 Rust Edition (#10806)* Update Wasmtime to the 2024 Rust EditionNow that our MSRV supports the 2024 edition it's possible to make thisswitch. This commit moves Wasmtime to the 2024 Edition to keepup-to-date with Rust idioms and access many of the edition featuresexclusive to the 2024 edition.prtest:full* Reformat with the 2024 edition List of files: /wasmtime-44.0.1/crates/wasmtime/src/runtime/vm/memory/malloc.rs

d5ee2a04 - Move MemoryImageSource::map_at to mmap module (#9687)

Fri, 06 Dec 2024 23:51:06 +0000

Move MemoryImageSource::map_at to mmap module (#9687)* Simplify mmap interface slightlyReturn a single `SendSyncPtr` -- the platform-independent context converts tothe various raw pointer types as desired. This simplifies upcoming work where Iwanted to return a `SendSyncPtr`.* Move MemoryImageSource::map_at to mmap moduleThis is part of the work to centralize memory management into the `mmap`module. This commit introduces a few structures which aid in that process, andstarts converting one of the functions (`MemoryImageSource::map_at`) into thismodule.The structures introduced are:* `MemoryBase`: `RuntimeLinearMemory::base_ptr` is now `RuntimeLinearMemory::base`, which returns a `MemoryBase`. This is either a raw pointer or an `MmapOffset` as described below.* `MmapOffset`: A combination of a reference to an mmap and an offset into it. Logically represents a pointer into a mapped section of memory.In future work, we'll move more image-mapping code over to `Mmap` instances. List of files: /wasmtime-44.0.1/crates/wasmtime/src/runtime/vm/memory/malloc.rs

9034e101 - Rely on `core::error::Error` (#9702)

Tue, 03 Dec 2024 18:27:28 +0000

Rely on `core::error::Error` (#9702)* Rely on `core::error::Error`With Wasmtime's new MSRV at 1.81 this means that `core::error::Error` isavailable which means that in `no_std` mode the `Error` trait can beused. This has been integrated into `anyhow::Error` already upstream andmeans that we can remove our own local hacks such as the `Err2Anyhow` trait.This commit removes the `Err2Anyhow` trait and all usage, going back toidiomatic Rust error propagation and conversion even in the `no_std`world. This should make code more portable by default and remove someweird idioms we had for supporting this.prtest:full* Add some trusted vets* Audit object crate update* Disable backtraces on CI List of files: /wasmtime-44.0.1/crates/wasmtime/src/runtime/vm/memory/malloc.rs

27ce0bab - Improve `MallocMemory` implementation (#9634)

Wed, 20 Nov 2024 19:13:02 +0000

Improve `MallocMemory` implementation (#9634)* Optimize memory growth in debug mode which was showing up locally in profiles as being particularly slow.* Fix a bug where the `memory_reservation_for_growth` was accidentally initialized instead of leaving it uninitialized as intended. List of files: /wasmtime-44.0.1/crates/wasmtime/src/runtime/vm/memory/malloc.rs

34504fed - Move `memory_init_cow` option to `Tunables` (#9632)

Wed, 20 Nov 2024 17:56:51 +0000

Move `memory_init_cow` option to `Tunables` (#9632)This commit moves the configuration option from `Config` to `Tunables`to ensure that the memory allocation backend has access to it and thenit's used to specifically avoid choosing a malloc-based memory becauseCoW isn't compatible with malloc. List of files: /wasmtime-44.0.1/crates/wasmtime/src/runtime/vm/memory/malloc.rs

d3132c9d - Add a `signals-based-traps` Cargo compile-time feature (#9614)

Tue, 19 Nov 2024 19:21:36 +0000

Add a `signals-based-traps` Cargo compile-time feature (#9614)* Gate signal handlers behind a new Cargo featureThis commit adds a new on-by-default Cargo feature to the `wasmtime`crate named `signals-based-traps`. This is modeled after the`Config::signals_based_traps` configuration at runtime and can be usedto statically disable the use of signal handlers in Wasmtime. Thisnotably reduces the number of platform dependencies that Wasmtime hasand provides a mode of avoiding relying on signals altogether.This introduces a new `MallocMemory` which is a linear memory backed bythe system allocator. This new type of memory is enabled when virtualmemory guards are disabled and signals-based-traps are disabled. Thismeans that this new type of memory will be candidate for fuzzing forexample.prtest:full* Fix rebase conflict* Refactor `MmapVec` documentation and representation* Remove no-longer-needed `Arc`* Document it may be backed by `Vec` List of files: /wasmtime-44.0.1/crates/wasmtime/src/runtime/vm/memory/malloc.rs