On Thu, Sep 12, 2024 at 09:54:01AM +0000, Alice Ryhl wrote: > Rust Binder holds incoming transactions in a read-only mmap'd region > where it manually manages the pages. These pages are only in use until > the incoming transaction is consumed by userspace, but the kernel will > keep the pages around for future transactions. Rust Binder registers a > shrinker with the kernel so that it can give back these pages if the > system comes under memory pressure. > > Separate types are provided for registered and unregistered shrinkers. > The unregistered shrinker type can be used to configure the shrinker > before registering it. Separating it into two types also enables the > user to construct the private data between the calls to `shrinker_alloc` > and `shrinker_register` and avoid constructing the private data if > allocating the shrinker fails. > > The user specifies the callbacks in use by implementing the Shrinker > trait for the type used for the private data. This requires specifying > three things: implementations for count_objects and scan_objects, and > the pointer type that the private data will be wrapped in. > > The return values of count_objects and scan_objects are provided using > new types called CountObjects and ScanObjects respectively. These types > prevent the user from e.g. returning SHRINK_STOP from count_objects or > returning SHRINK_EMPTY from scan_objects. > > Signed-off-by: Alice Ryhl <aliceryhl@xxxxxxxxxx> > --- [...] > --- a/rust/kernel/lib.rs > +++ b/rust/kernel/lib.rs > @@ -45,6 +45,7 @@ > pub mod prelude; > pub mod print; > pub mod rbtree; > +pub mod shrinker; Meta comment: I think we should create a mm mod (memory management) and put shrinker there, otherwise there would be a very long list of "pub mod" in rust/kernel/lib.rs ;-) Thoughts? Regards, Boqun > mod static_assert; > #[doc(hidden)] > pub mod std_vendor; > diff --git a/rust/kernel/shrinker.rs b/rust/kernel/shrinker.rs > new file mode 100644 > index 000000000000..9af726bfe0b1 [...]
