pageserver: switch to jemalloc (#8307)

## Problem

- Resident memory on long running pageserver processes tends to climb:
memory fragmentation is suspected.
- Total resident memory may be a limiting factor for running on smaller
nodes.

## Summary of changes

- As a low-energy experiment, switch the pageserver to use jemalloc (not
a net-new dependency, proxy already use it)
- Decide at end of week whether to revert before next release.

Cargo.lock

@@ -3667,6 +3667,7 @@ dependencies = [
  "sysinfo",
  "tenant_size_model",
  "thiserror",
+ "tikv-jemallocator",
  "tokio",
  "tokio-epoll-uring",
  "tokio-io-timeout",
@@ -7468,6 +7469,7 @@ dependencies = [
  "syn 1.0.109",
  "syn 2.0.52",
  "sync_wrapper",
+ "tikv-jemalloc-sys",
  "time",
  "time-macros",
  "tokio",

pageserver/Cargo.toml

@@ -62,6 +62,7 @@ sync_wrapper.workspace = true
 sysinfo.workspace = true
 tokio-tar.workspace = true
 thiserror.workspace = true
+tikv-jemallocator.workspace = true
 tokio = { workspace = true, features = ["process", "sync", "fs", "rt", "io-util", "time"] }
 tokio-epoll-uring.workspace = true
 tokio-io-timeout.workspace = true

pageserver/src/bin/pageserver.rs

@@ -47,6 +47,9 @@ use utils::{
 project_git_version!(GIT_VERSION);
 project_build_tag!(BUILD_TAG);
 
+#[global_allocator]
+static GLOBAL: tikv_jemallocator::Jemalloc = tikv_jemallocator::Jemalloc;
+
 const PID_FILE_NAME: &str = "pageserver.pid";
 
 const FEATURES: &[&str] = &[

workspace_hack/Cargo.toml

@@ -69,6 +69,7 @@ sha2 = { version = "0.10", features = ["asm"] }
 smallvec = { version = "1", default-features = false, features = ["const_new", "write"] }
 subtle = { version = "2" }
 sync_wrapper = { version = "0.1", default-features = false, features = ["futures"] }
+tikv-jemalloc-sys = { version = "0.5" }
 time = { version = "0.3", features = ["macros", "serde-well-known"] }
 tokio = { version = "1", features = ["fs", "io-std", "io-util", "macros", "net", "process", "rt-multi-thread", "signal", "test-util"] }
 tokio-rustls = { version = "0.24" }