Auto merge of #148925 - madsmtm:jemalloc-perf, r=<try>

rust-bors[bot] · web-flow · commit f30bc23f4189 · 2025-11-13T22:05:14.000Z
Fix performance regression with jemalloc
diff --git a/Cargo.lock b/Cargo.lock
@@ -600,7 +600,6 @@ dependencies = [
  "serde_json",
  "tempfile",
  "termize",
- "tikv-jemalloc-sys",
  "toml 0.9.7",
  "ui_test",
  "walkdir",
@@ -4807,7 +4806,6 @@ dependencies = [
  "stringdex",
  "tempfile",
  "threadpool",
- "tikv-jemalloc-sys",
  "tracing",
  "tracing-subscriber",
  "tracing-tree",
diff --git a/src/librustdoc/Cargo.toml b/src/librustdoc/Cargo.toml
@@ -24,7 +24,6 @@ smallvec = "1.8.1"
 stringdex = "=0.0.3"
 tempfile = "3"
 threadpool = "1.8.1"
-tikv-jemalloc-sys = { version = "0.6.1", optional = true, features = ['override_allocator_on_supported_platforms'] }
 tracing = "0.1"
 tracing-tree = "0.3.0"
 unicode-segmentation = "1.9"
@@ -43,7 +42,7 @@ minifier = { version = "0.3.2", default-features = false }
 expect-test = "1.4.0"
 
 [features]
-jemalloc = ["dep:tikv-jemalloc-sys"]
+jemalloc = []
 
 [package.metadata.rust-analyzer]
 rustc_private = true
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
@@ -61,6 +61,14 @@ extern crate rustc_target;
 extern crate rustc_trait_selection;
 extern crate test;
 
+/// See docs in https://github.com/rust-lang/rust/blob/HEAD/compiler/rustc/src/main.rs
+/// and https://github.com/rust-lang/rust/pull/146627 for why we need this.
+///
+/// NOTE: This is loaded from the sysroot that was built with the other `rustc` crates above, for
+/// some unknown reason this is more performant than building this with Cargo.
+#[cfg(feature = "jemalloc")]
+extern crate tikv_jemalloc_sys as _;
+
 use std::env::{self, VarError};
 use std::io::{self, IsTerminal};
 use std::path::Path;
@@ -72,10 +80,6 @@ use rustc_interface::interface;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::config::{ErrorOutputType, RustcOptGroup, make_crate_type_option};
 use rustc_session::{EarlyDiagCtxt, getopts};
-/// See docs in https://github.com/rust-lang/rust/blob/HEAD/compiler/rustc/src/main.rs
-/// and https://github.com/rust-lang/rust/pull/146627 for why we need this `use` statement.
-#[cfg(feature = "jemalloc")]
-use tikv_jemalloc_sys as _;
 use tracing::info;
 
 use crate::clean::utils::DOC_RUST_LANG_ORG_VERSION;
diff --git a/src/tools/clippy/Cargo.toml b/src/tools/clippy/Cargo.toml
@@ -31,7 +31,6 @@ tempfile = { version = "3.20", optional = true }
 termize = "0.2"
 color-print = "0.3.4"
 anstream = "0.6.18"
-tikv-jemalloc-sys = { version = "0.6.1", optional = true, features = ['override_allocator_on_supported_platforms'] }
 
 [dev-dependencies]
 cargo_metadata = "0.18.1"
@@ -57,7 +56,7 @@ rustc_tools_util = { path = "rustc_tools_util", version = "0.4.2" }
 [features]
 integration = ["dep:tempfile"]
 internal = ["dep:clippy_lints_internal", "dep:tempfile"]
-jemalloc = ["dep:tikv-jemalloc-sys"]
+jemalloc = []
 
 [package.metadata.rust-analyzer]
 # This package uses #[feature(rustc_private)]
diff --git a/src/tools/clippy/src/driver.rs b/src/tools/clippy/src/driver.rs
@@ -14,9 +14,12 @@ extern crate rustc_session;
 extern crate rustc_span;
 
 /// See docs in https://github.com/rust-lang/rust/blob/HEAD/compiler/rustc/src/main.rs
-/// and https://github.com/rust-lang/rust/pull/146627 for why we need this `use` statement.
+/// and https://github.com/rust-lang/rust/pull/146627 for why we need this.
+///
+/// NOTE: This is loaded from the sysroot that was built with the other `rustc` crates above, for
+/// some unknown reason this is more performant than building this with Cargo.
 #[cfg(feature = "jemalloc")]
-use tikv_jemalloc_sys as _;
+extern crate tikv_jemalloc_sys as _;
 
 use clippy_utils::sym;
 use declare_clippy_lint::LintListBuilder;
