New upstream version 1.23.0+dfsg1

[rustc.git] / src / doc / unstable-book / src / library-features / alloc-jemalloc.md

diff --git a/src/doc/unstable-book/src/library-features/alloc-jemalloc.md b/src/doc/unstable-book/src/library-features/alloc-jemalloc.md
index 18ff838dd32b961743f14b03a95d13d0d14790f9..425d4cb79b2df7e359fbd0c05edd3c8155d3156c 100644 (file)
--- a/src/doc/unstable-book/src/library-features/alloc-jemalloc.md
+++ b/src/doc/unstable-book/src/library-features/alloc-jemalloc.md
@@ -8,55 +8,6 @@ See also [`alloc_system`](library-features/alloc-system.html).
 
 ------------------------
 
-The compiler currently ships two default allocators: `alloc_system` and
-`alloc_jemalloc` (some targets don't have jemalloc, however). These allocators
-are normal Rust crates and contain an implementation of the routines to
-allocate and deallocate memory. The standard library is not compiled assuming
-either one, and the compiler will decide which allocator is in use at
-compile-time depending on the type of output artifact being produced.
-
-Binaries generated by the compiler will use `alloc_jemalloc` by default (where
-available). In this situation the compiler "controls the world" in the sense of
-it has power over the final link. Primarily this means that the allocator
-decision can be left up the compiler.
-
-Dynamic and static libraries, however, will use `alloc_system` by default. Here
-Rust is typically a 'guest' in another application or another world where it
-cannot authoritatively decide what allocator is in use. As a result it resorts
-back to the standard APIs (e.g. `malloc` and `free`) for acquiring and releasing
-memory.
-
-# Switching Allocators
-
-Although the compiler's default choices may work most of the time, it's often
-necessary to tweak certain aspects. Overriding the compiler's decision about
-which allocator is in use is done simply by linking to the desired allocator:
-
-```rust,no_run
-#![feature(alloc_system)]
-
-extern crate alloc_system;
-
-fn main() {
-    let a = Box::new(4); // Allocates from the system allocator.
-    println!("{}", a);
-}
-```
-
-In this example the binary generated will not link to jemalloc by default but
-instead use the system allocator. Conversely to generate a dynamic library which
-uses jemalloc by default one would write:
-
-```rust,ignore
-#![feature(alloc_jemalloc)]
-#![crate_type = "dylib"]
-
-extern crate alloc_jemalloc;
-
-pub fn foo() {
-    let a = Box::new(4); // Allocates from jemalloc.
-    println!("{}", a);
-}
-# fn main() {}
-```
+This feature has been replaced by [the `jemallocator` crate on crates.io.][jemallocator].
 
+[jemallocator]: https://crates.io/crates/jemallocator