Add profiling_libunwind feature

jemalloc-ctl/Cargo.toml

@@ -37,6 +37,7 @@ tikv-jemallocator = { path = "../jemallocator", version = "0.6.1" }
 default = []
 stats = ["tikv-jemalloc-sys/stats"]
 profiling = ["tikv-jemalloc-sys/profiling"]
+profiling_libunwind = ["tikv-jemalloc-sys/profiling_libunwind", "profiling"]
 use_std = [ "libc/use_std" ]
 disable_initial_exec_tls = ["tikv-jemalloc-sys/disable_initial_exec_tls"]
 

jemalloc-sys/Cargo.toml

@@ -41,6 +41,7 @@ cc = "^1.0.13"
 [features]
 default = ["background_threads_runtime_support"]
 profiling = []
+profiling_libunwind = ["profiling"]
 debug = []
 background_threads_runtime_support = []
 background_threads = [ "background_threads_runtime_support" ]

jemalloc-sys/README.md

@@ -45,6 +45,15 @@ This crate provides following cargo feature flags:
   * `libgcc` (unless --disable-prof-libgcc)
   * `gcc intrinsics` (unless --disable-prof-gcc)
 
+* `profiling_libunwind` (configure `jemalloc` with `--enable-prof-libunwind`):
+  Force jemalloc to use `libunwind` for backtracing during heap profiling
+  instead of the default gcc-based unwinding, which has a
+  [known livelock bug](https://github.com/jemalloc/jemalloc/issues/2282) in
+  multi-threaded programs using `_Unwind_Backtrace`. Enables `profiling`
+  automatically. On Linux, this requires `libunwind-dev` (or `libunwind-devel`)
+  to be installed. On macOS/iOS, unwind symbols are provided by the system and
+  no extra library is needed.
+
 * `stats` (configure `jemalloc` with `--enable-stats`): Enable statistics
   gathering functionality. See the `jemalloc`'s "`opt.stats_print`" option
   documentation for usage details.

jemalloc-sys/build.rs

@@ -284,6 +284,17 @@ fn main() {
         cmd.arg("--enable-prof");
     }
 
+    if env::var("CARGO_FEATURE_PROFILING_LIBUNWIND").is_ok() {
+        info!("CARGO_FEATURE_PROFILING_LIBUNWIND set");
+        cmd.arg("--enable-prof-libunwind");
+        // On Apple platforms unwind symbols live in libSystem, and on
+        // Windows libunwind is not available. Everywhere else (Linux,
+        // FreeBSD, etc.) we need to link it explicitly.
+        if !target.contains("apple") && !target.contains("windows") {
+            println!("cargo:rustc-link-lib=unwind");
+        }
+    }
+
     if env::var("CARGO_FEATURE_STATS").is_ok() {
         info!("CARGO_FEATURE_STATS set");
         cmd.arg("--enable-stats");

jemallocator/Cargo.toml

@@ -48,6 +48,7 @@ tikv-jemalloc-ctl = { path = "../jemalloc-ctl", version = "0.6.1" }
 default = ["background_threads_runtime_support"]
 alloc_trait = []
 profiling = ["tikv-jemalloc-sys/profiling"]
+profiling_libunwind = ["tikv-jemalloc-sys/profiling_libunwind", "profiling"]
 debug = ["tikv-jemalloc-sys/debug"]
 stats = ["tikv-jemalloc-sys/stats"]
 background_threads_runtime_support = ["tikv-jemalloc-sys/background_threads_runtime_support"]