diff --git a/rust-version b/rust-version
index a48a44e5d1..25a5238f53 100644
--- a/rust-version
+++ b/rust-version
@@ -1 +1 @@
-9e71b3bc704eea68d39bd0f6a46703c7d22f5d3b
+390279b302ca98ae270f434100ae3730531d1246
diff --git a/src/building/optimized-build.md b/src/building/optimized-build.md
index 0a6b82eba4..a9c19fa585 100644
--- a/src/building/optimized-build.md
+++ b/src/building/optimized-build.md
@@ -31,11 +31,11 @@ Enabling LTO on Linux has [produced] speed-ups by up to 10%.
 ## Memory allocator
 
 Using a different memory allocator for `rustc` can provide significant performance benefits.
-If you want to enable the `jemalloc` allocator, you can set the `rust.jemalloc` option to `true`
+If you want to enable the `jemalloc` allocator, you can set the `rust.override-allocator` option to `jemalloc`
 in `bootstrap.toml`:
 
 ```toml
-rust.jemalloc = true
+rust.override-allocator = "jemalloc"
 ```
 
 > Note that this option is currently only supported for Linux and macOS targets.
diff --git a/src/profiling/with-perf.md b/src/profiling/with-perf.md
index 50281b6b60..3285a486eb 100644
--- a/src/profiling/with-perf.md
+++ b/src/profiling/with-perf.md
@@ -7,7 +7,7 @@ This is a guide for how to profile rustc with [perf](https://perf.wiki.kernel.or
 - Get a clean checkout of rust-lang/rust
 - Set the following settings in your `bootstrap.toml`:
   - `rust.debuginfo-level = 1` - enables line debuginfo
-  - `rust.jemalloc = false` - lets you do memory use profiling with valgrind
+  - leave `rust.override-allocator` unset - lets you do memory use profiling with valgrind
   - leave everything else the defaults
 - Run `./x build` to get a full build
 - Make a rustup toolchain pointing to that result