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Update Heap Allocation post for #763

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Philipp Oppermann
2020-03-06 11:50:23 +01:00
parent bdf161aa7d
commit bf4c928214
1 changed files with 5 additions and 5 deletions
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blog/content/second-edition/posts/10-heap-allocation/index.md
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@@ -515,7 +515,7 @@ To use the crate, we first need to add a dependency on it in our `Cargo.toml`:
# in Cargo.toml # in Cargo.toml
[dependencies] [dependencies]
linked_list_allocator = "0.6.4" linked_list_allocator = "0.8.0"
``` ```
Then we can replace our dummy allocator with the allocator provided by the crate: Then we can replace our dummy allocator with the allocator provided by the crate:
@@ -535,7 +535,7 @@ The struct is named `LockedHeap` because it uses a [`spin::Mutex`] for synchroni
Setting the `LockedHeap` as global allocator is not enough. The reason is that we use the [`empty`] constructor function, which creates an allocator without any backing memory. Like our dummy allocator, it always returns an error on `alloc`. To fix this, we need to initialize the allocator after creating the heap: Setting the `LockedHeap` as global allocator is not enough. The reason is that we use the [`empty`] constructor function, which creates an allocator without any backing memory. Like our dummy allocator, it always returns an error on `alloc`. To fix this, we need to initialize the allocator after creating the heap:
[`empty`]: https://docs.rs/linked_list_allocator/0.6.4/linked_list_allocator/struct.LockedHeap.html#method.empty [`empty`]: https://docs.rs/linked_list_allocator/0.8.0/linked_list_allocator/struct.LockedHeap.html#method.empty
```rust ```rust
// in src/allocator.rs // in src/allocator.rs
@@ -557,9 +557,9 @@ pub fn init_heap(
We use the [`LockedHeap::lock`] method to get an exclusive reference to the wrapped [`Heap`] instance, on which we then call the [`init`] method with the heap bounds as arguments. It is important that we initialize the heap _after_ mapping the heap pages, since the [`init`] function already tries to write to the heap memory. We use the [`LockedHeap::lock`] method to get an exclusive reference to the wrapped [`Heap`] instance, on which we then call the [`init`] method with the heap bounds as arguments. It is important that we initialize the heap _after_ mapping the heap pages, since the [`init`] function already tries to write to the heap memory.
[`LockedHeap::lock`]: https://docs.rs/linked_list_allocator/0.6.4/linked_list_allocator/struct.LockedHeap.html#method.lock [`LockedHeap::lock`]: https://docs.rs/linked_list_allocator/0.8.0/linked_list_allocator/struct.LockedHeap.html#method.lock
[`Heap`]: https://docs.rs/linked_list_allocator/0.6.4/linked_list_allocator/struct.Heap.html [`Heap`]: https://docs.rs/linked_list_allocator/0.8.0/linked_list_allocator/struct.Heap.html
[`init`]: https://docs.rs/linked_list_allocator/0.6.4/linked_list_allocator/struct.Heap.html#method.init [`init`]: https://docs.rs/linked_list_allocator/0.8.0/linked_list_allocator/struct.Heap.html#method.init
After initializing the heap, we can now use all allocation and collection types of the built-in [`alloc`] crate without error: After initializing the heap, we can now use all allocation and collection types of the built-in [`alloc`] crate without error: