Add heap usage stats with defmt (#2619)

* feat(esp-alloc): Add heap usage stats and provide `esp_alloc::get_info!()` macro

* refactor(esp-alloc): Feature gate internal memory usage that requires extra computation.

- Introduce the `internal-heap-stats` feature for `esp-alloc`.
- Add `esp_alloc::get_info!()` to `psram_quad` example to show usage and
ensure coverage of the feature in tests.

* refactor(esp-alloc): Remove `get_info!()` macro in favour of documenting `HEAP.stats()`

* Implement defmt::Format for HeapStats and RegionStats

* rustfmt

* show usage percent + move bar drawing logic to separate functions

* update doc comments

* Fixed a typo in qa-test/src/bin/psram_quad.rs

Co-authored-by: Scott Mabin <[email protected]>

* minor improvements to write bar functions

* Aligned the indentation in Cargo.toml

Co-authored-by: Kirill Mikhailov <[email protected]>

* Fixed a typo in docs

Co-authored-by: Kirill Mikhailov <[email protected]>

* Nitpicking x2

Co-authored-by: Kirill Mikhailov <[email protected]>

* Surround a function call with backticks

Co-authored-by: Kirill Mikhailov <[email protected]>

* rustfmt

---------

Co-authored-by: Anthony Grondin <[email protected]>
Co-authored-by: Scott Mabin <[email protected]>
Co-authored-by: Kirill Mikhailov <[email protected]>

Author: 4 people

esp-alloc/CHANGELOG.md

@@ -9,6 +9,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- `esp_alloc::HEAP.stats()` can now be used to get heap usage informations (#2137)
+
 ### Changed
 
 ### Fixed

esp-alloc/Cargo.toml

@@ -23,10 +23,24 @@ default-target = "riscv32imc-unknown-none-elf"
 features       = ["nightly"]
 
 [dependencies]
+defmt                 = { version = "0.3.8", optional = true }
+cfg-if                = "1.0.0"
 critical-section      = "1.1.3"
 enumset               = "1.1.5"
 linked_list_allocator = { version = "0.10.5", default-features = false, features = ["const_mut_refs"] }
+document-features     = "0.2.10"
 
 [features]
 default = []
 nightly = []
+
+## Implement `defmt::Format` on certain types.
+defmt = ["dep:defmt"]
+
+## Enable this feature if you want to keep stats about the internal heap usage such as:
+## - Max memory usage since initialization of the heap
+## - Total allocated memory since initialization of the heap
+## - Total freed memory since initialization of the heap
+##
+## ⚠️ Note: Enabling this feature will require extra computation every time alloc/dealloc is called.
+internal-heap-stats = []