add preferred jemalloc config

add muzzy/dirty configuration mallctl interface

add program argument for --gc-muzzy=false

Signed-off-by: Jason Volk <jason@zemos.net>

Cargo.lock

@@ -175,9 +175,9 @@ checksum = "ace50bade8e6234aa140d9a2f552bbee1db4d353f69b8217bc503490fc1a9f26"
 
 [[package]]
 name = "aws-lc-rs"
-version = "1.12.0"
+version = "1.12.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f409eb70b561706bf8abba8ca9c112729c481595893fd06a2dd9af8ed8441148"
+checksum = "1ea835662a0af02443aa1396d39be523bbf8f11ee6fad20329607c480bea48c3"
 dependencies = [
  "aws-lc-sys",
  "paste",
@@ -186,9 +186,9 @@ dependencies = [
 
 [[package]]
 name = "aws-lc-sys"
-version = "0.24.1"
+version = "0.25.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "923ded50f602b3007e5e63e3f094c479d9c8a9b42d7f4034e4afe456aa48bfd2"
+checksum = "71b2ddd3ada61a305e1d8bb6c005d1eaa7d14d903681edfc400406d523a9b491"
 dependencies = [
  "bindgen",
  "cc",
@@ -368,7 +368,7 @@ version = "0.69.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "271383c67ccabffb7381723dea0672a673f292304fcb45c01cc648c7a8d58088"
 dependencies = [
- "bitflags 2.7.0",
+ "bitflags 2.8.0",
  "cexpr",
  "clang-sys",
  "itertools 0.12.1",
@@ -393,9 +393,9 @@ checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
 [[package]]
 name = "bitflags"
-version = "2.7.0"
+version = "2.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1be3f42a67d6d345ecd59f675f3f012d6974981560836e938c22b424b85ce1be"
+checksum = "8f68f53c83ab957f72c32642f3868eec03eb974d1fb82e453128456482613d36"
 
 [[package]]
 name = "blake2"
@@ -495,9 +495,9 @@ dependencies = [
 
 [[package]]
 name = "cc"
-version = "1.2.9"
+version = "1.2.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c8293772165d9345bdaaa39b45b2109591e63fe5e6fbc23c6ff930a048aa310b"
+checksum = "13208fcbb66eaeffe09b99fffbe1af420f00a7b35aa99ad683dfc1aa76145229"
 dependencies = [
  "jobserver",
  "libc",
@@ -1047,7 +1047,7 @@ version = "0.28.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "829d955a0bb380ef178a640b91779e3987da38c9aea133b20614cfed8cdea9c6"
 dependencies = [
- "bitflags 2.7.0",
+ "bitflags 2.8.0",
  "crossterm_winapi",
  "futures-core",
  "mio",
@@ -1122,9 +1122,9 @@ checksum = "817fa642fb0ee7fe42e95783e00e0969927b96091bdd4b9b1af082acd943913b"
 
 [[package]]
 name = "data-encoding"
-version = "2.6.0"
+version = "2.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e8566979429cf69b49a5c740c60791108e86440e8be149bbea4fe54d2c32d6e2"
+checksum = "0e60eed09d8c01d3cee5b7d30acb059b76614c918fa0f992e0dd6eeb10daad6f"
 
 [[package]]
 name = "date_header"
@@ -2378,7 +2378,7 @@ version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "71e2746dc3a24dd78b3cfcb7be93368c6de9963d30f43a6a73998a9cf4b17b46"
 dependencies = [
- "bitflags 2.7.0",
+ "bitflags 2.8.0",
  "cfg-if",
  "cfg_aliases",
  "libc",
@@ -2911,7 +2911,7 @@ version = "0.12.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f86ba2052aebccc42cbbb3ed234b8b13ce76f75c3551a303cb2bcffcff12bb14"
 dependencies = [
- "bitflags 2.7.0",
+ "bitflags 2.8.0",
  "memchr",
  "pulldown-cmark-escape",
  "unicase",
@@ -3032,7 +3032,7 @@ version = "0.5.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "03a862b389f93e68874fbf580b9de08dd02facb9a788ebadaf4a3fd33cf58834"
 dependencies = [
- "bitflags 2.7.0",
+ "bitflags 2.8.0",
 ]
 
 [[package]]
@@ -3377,7 +3377,7 @@ dependencies = [
 [[package]]
 name = "rust-librocksdb-sys"
 version = "0.31.0+9.9.3"
-source = "git+https://github.com/girlbossceo/rust-rocksdb-zaidoon1?rev=123d6302fed23fc706344becb2f19623265a83f8#123d6302fed23fc706344becb2f19623265a83f8"
+source = "git+https://github.com/girlbossceo/rust-rocksdb-zaidoon1?rev=2d31cf323df7c6d95396ef0213e28936c2218bd6#2d31cf323df7c6d95396ef0213e28936c2218bd6"
 dependencies = [
  "bindgen",
  "bzip2-sys",
@@ -3394,7 +3394,7 @@ dependencies = [
 [[package]]
 name = "rust-rocksdb"
 version = "0.35.0"
-source = "git+https://github.com/girlbossceo/rust-rocksdb-zaidoon1?rev=123d6302fed23fc706344becb2f19623265a83f8#123d6302fed23fc706344becb2f19623265a83f8"
+source = "git+https://github.com/girlbossceo/rust-rocksdb-zaidoon1?rev=2d31cf323df7c6d95396ef0213e28936c2218bd6#2d31cf323df7c6d95396ef0213e28936c2218bd6"
 dependencies = [
  "libc",
  "rust-librocksdb-sys",
@@ -3441,7 +3441,7 @@ version = "0.38.43"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "a78891ee6bf2340288408954ac787aa063d8e8817e9f53abb37c695c6d834ef6"
 dependencies = [
- "bitflags 2.7.0",
+ "bitflags 2.8.0",
  "errno",
  "libc",
  "linux-raw-sys",
@@ -3559,9 +3559,12 @@ checksum = "94143f37725109f92c262ed2cf5e59bce7498c01bcc1502d7b9afe439a4e9f49"
 
 [[package]]
 name = "sd-notify"
-version = "0.4.3"
+version = "0.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1be20c5f7f393ee700f8b2f28ea35812e4e212f40774b550cd2a93ea91684451"
+checksum = "561e6b346a5e59e0b8a07894004897d7160567e3352d2ebd6c3741d4e086b6f5"
+dependencies = [
+ "libc",
+]
 
 [[package]]
 name = "security-framework"
@@ -3569,7 +3572,7 @@ version = "3.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "271720403f46ca04f7ba6f55d438f8bd878d6b8ca0a1046e8228c4145bcbb316"
 dependencies = [
- "bitflags 2.7.0",
+ "bitflags 2.8.0",
  "core-foundation",
  "core-foundation-sys",
  "libc",
@@ -4171,7 +4174,7 @@ dependencies = [
 [[package]]
 name = "tikv-jemalloc-ctl"
 version = "0.6.0"
-source = "git+https://github.com/girlbossceo/jemallocator?rev=d87938bfddc26377dd7fdf14bbcd345f3ab19442#d87938bfddc26377dd7fdf14bbcd345f3ab19442"
+source = "git+https://github.com/girlbossceo/jemallocator?rev=82af58d6a13ddd5dcdc7d4e91eae3b63292995b8#82af58d6a13ddd5dcdc7d4e91eae3b63292995b8"
 dependencies = [
  "libc",
  "paste",
@@ -4181,7 +4184,7 @@ dependencies = [
 [[package]]
 name = "tikv-jemalloc-sys"
 version = "0.6.0+5.3.0-1-ge13ca993e8ccb9ba9847cc330696e02839f328f7"
-source = "git+https://github.com/girlbossceo/jemallocator?rev=d87938bfddc26377dd7fdf14bbcd345f3ab19442#d87938bfddc26377dd7fdf14bbcd345f3ab19442"
+source = "git+https://github.com/girlbossceo/jemallocator?rev=82af58d6a13ddd5dcdc7d4e91eae3b63292995b8#82af58d6a13ddd5dcdc7d4e91eae3b63292995b8"
 dependencies = [
  "cc",
  "libc",
@@ -4190,7 +4193,7 @@ dependencies = [
 [[package]]
 name = "tikv-jemallocator"
 version = "0.6.0"
-source = "git+https://github.com/girlbossceo/jemallocator?rev=d87938bfddc26377dd7fdf14bbcd345f3ab19442#d87938bfddc26377dd7fdf14bbcd345f3ab19442"
+source = "git+https://github.com/girlbossceo/jemallocator?rev=82af58d6a13ddd5dcdc7d4e91eae3b63292995b8#82af58d6a13ddd5dcdc7d4e91eae3b63292995b8"
 dependencies = [
  "libc",
  "tikv-jemalloc-sys",
@@ -4445,7 +4448,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "403fa3b783d4b626a8ad51d766ab03cb6d2dbfc46b1c5d4448395e6628dc9697"
 dependencies = [
  "async-compression",
- "bitflags 2.7.0",
+ "bitflags 2.8.0",
  "bytes",
  "futures-core",
  "futures-util",
@@ -4709,9 +4712,9 @@ dependencies = [
 
 [[package]]
 name = "valuable"
-version = "0.1.0"
+version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "830b7e5d4d90034032940e4ace0d9a9a057e7a45cd94e6c007832e39edb82f6d"
+checksum = "ba73ea9cf16a25df0c8caa16c51acb937d5712a8429db78a3ee29d5dcacd3a65"
 
 [[package]]
 name = "vcpkg"

Cargo.toml

@@ -431,17 +431,23 @@ version = "0.35.0"
 # jemalloc usage
 [workspace.dependencies.tikv-jemalloc-sys]
 git = "https://github.com/girlbossceo/jemallocator"
-rev = "d87938bfddc26377dd7fdf14bbcd345f3ab19442"
+rev = "82af58d6a13ddd5dcdc7d4e91eae3b63292995b8"
 default-features = false
-features = ["unprefixed_malloc_on_supported_platforms"]
+features = [
+	"background_threads_runtime_support",
+	"unprefixed_malloc_on_supported_platforms",
+]
 [workspace.dependencies.tikv-jemallocator]
 git = "https://github.com/girlbossceo/jemallocator"
-rev = "d87938bfddc26377dd7fdf14bbcd345f3ab19442"
+rev = "82af58d6a13ddd5dcdc7d4e91eae3b63292995b8"
 default-features = false
-features = ["unprefixed_malloc_on_supported_platforms"]
+features = [
+	"background_threads_runtime_support",
+	"unprefixed_malloc_on_supported_platforms",
+]
 [workspace.dependencies.tikv-jemalloc-ctl]
 git = "https://github.com/girlbossceo/jemallocator"
-rev = "d87938bfddc26377dd7fdf14bbcd345f3ab19442"
+rev = "82af58d6a13ddd5dcdc7d4e91eae3b63292995b8"
 default-features = false
 features = ["use_std"]
 

deps/rust-rocksdb/Cargo.toml

@@ -27,7 +27,7 @@ malloc-usable-size = ["rust-rocksdb/malloc-usable-size"]
 
 [dependencies.rust-rocksdb]
 git = "https://github.com/girlbossceo/rust-rocksdb-zaidoon1"
-rev = "123d6302fed23fc706344becb2f19623265a83f8"
+rev = "2d31cf323df7c6d95396ef0213e28936c2218bd6"
 #branch = "master"
 default-features = false
 

src/admin/debug/commands.rs

@@ -967,7 +967,7 @@ pub(super) async fn database_stats(
 
 #[admin_command]
 pub(super) async fn trim_memory(&self) -> Result<RoomMessageEventContent> {
-	conduwuit::alloc::trim()?;
+	conduwuit::alloc::trim(None)?;
 
 	writeln!(self, "done").await?;
 

src/core/Cargo.toml

@@ -36,6 +36,7 @@ jemalloc_stats = [
     "tikv-jemalloc-ctl/stats",
     "tikv-jemallocator/stats",
 ]
+jemalloc_conf = []
 hardened_malloc = [
 	"dep:hardened_malloc-rs"
 ]

src/core/alloc/default.rs

@@ -1,7 +1,7 @@
 //! Default allocator with no special features
 
 /// Always returns Ok
-pub fn trim() -> crate::Result { Ok(()) }
+pub fn trim<I: Into<Option<usize>>>(_: I) -> crate::Result { Ok(()) }
 
 /// Always returns None
 #[must_use]

src/core/alloc/hardened.rs

@@ -3,7 +3,7 @@
 #[global_allocator]
 static HMALLOC: hardened_malloc_rs::HardenedMalloc = hardened_malloc_rs::HardenedMalloc;
 
-pub fn trim() -> crate::Result { Ok(()) }
+pub fn trim<I: Into<Option<usize>>>(_: I) -> crate::Result { Ok(()) }
 
 #[must_use]
 //TODO: get usage

src/core/alloc/je.rs

@@ -2,8 +2,9 @@
 
 use std::{
 	cell::OnceCell,
-	ffi::{c_char, c_void},
+	ffi::{c_char, c_void, CStr},
 	fmt::Debug,
+	sync::RwLock,
 };
 
 use arrayvec::ArrayVec;
@@ -11,10 +12,14 @@ use tikv_jemalloc_ctl as mallctl;
 use tikv_jemalloc_sys as ffi;
 use tikv_jemallocator as jemalloc;
 
-use crate::{err, is_equal_to, utils::math::Tried, Result};
+use crate::{
+	err, is_equal_to, is_nonzero,
+	utils::{math, math::Tried},
+	Result,
+};
 
 #[cfg(feature = "jemalloc_conf")]
-#[no_mangle]
+#[unsafe(no_mangle)]
 pub static malloc_conf: &[u8] = b"\
 metadata_thp:always\
 ,percpu_arena:percpu\
@@ -22,19 +27,26 @@ metadata_thp:always\
 ,max_background_threads:-1\
 ,lg_extent_max_active_fit:4\
 ,oversize_threshold:33554432\
-,tcache_max:2097152\
+,tcache_max:1048576\
 ,dirty_decay_ms:16000\
 ,muzzy_decay_ms:144000\
 \0";
 
 #[global_allocator]
 static JEMALLOC: jemalloc::Jemalloc = jemalloc::Jemalloc;
+static CONTROL: RwLock<()> = RwLock::new(());
 
-type Key = ArrayVec<usize, KEY_SEGS>;
 type Name = ArrayVec<u8, NAME_MAX>;
+type Key = ArrayVec<usize, KEY_SEGS>;
 
-const KEY_SEGS: usize = 8;
 const NAME_MAX: usize = 128;
+const KEY_SEGS: usize = 8;
+
+#[crate::ctor]
+fn _static_initialization() {
+	acq_epoch().expect("pre-initialization of jemalloc failed");
+	acq_epoch().expect("pre-initialization of jemalloc failed");
+}
 
 #[must_use]
 #[cfg(feature = "jemalloc_stats")]
@@ -49,6 +61,9 @@ pub fn memory_usage() -> Option<String> {
 		kibs / 1024.0
 	};
 
+	// Acquire the epoch; ensure latest stats are pulled in
+	acq_epoch().ok()?;
+
 	let allocated = mibs(stats::allocated::read());
 	let active = mibs(stats::active::read());
 	let mapped = mibs(stats::mapped::read());
@@ -76,6 +91,9 @@ pub fn memory_stats(opts: &str) -> Option<String> {
 		.into_raw()
 		.cast_const();
 
+	// Acquire the epoch; ensure latest stats are pulled in
+	acq_epoch().ok()?;
+
 	// SAFETY: calls malloc_stats_print() with our string instance which must remain
 	// in this frame. https://docs.rs/tikv-jemalloc-sys/latest/tikv_jemalloc_sys/fn.malloc_stats_print.html
 	unsafe { ffi::malloc_stats_print(Some(malloc_stats_cb), opaque, opts_p) };
@@ -95,7 +113,7 @@ unsafe extern "C" fn malloc_stats_cb(opaque: *mut c_void, msg: *const c_char) {
 	};
 
 	// SAFETY: we have to trust the string is null terminated.
-	let msg = unsafe { std::ffi::CStr::from_ptr(msg) };
+	let msg = unsafe { CStr::from_ptr(msg) };
 
 	let msg = String::from_utf8_lossy(msg.to_bytes());
 	res.push_str(msg.as_ref());
@@ -114,58 +132,168 @@ macro_rules! mallctl {
 	}};
 }
 
-pub fn trim() -> Result { set(&mallctl!("arena.4096.purge"), ()) }
-
-pub fn decay() -> Result { set(&mallctl!("arena.4096.purge"), ()) }
-
-pub fn set_by_name<T: Copy + Debug>(name: &str, val: T) -> Result { set(&key(name)?, val) }
-
-pub fn get_by_name<T: Copy + Debug>(name: &str) -> Result<T> { get(&key(name)?) }
-
 pub mod this_thread {
-	use super::{get, key, set, Key, OnceCell, Result};
+	use super::{is_nonzero, key, math, Debug, Key, OnceCell, Result};
 
-	pub fn trim() -> Result {
+	pub fn trim() -> Result { notify(mallctl!("arena.0.purge")) }
-		let mut key = mallctl!("arena.0.purge");
+
-		key[1] = arena_id()?.try_into()?;
+	pub fn decay() -> Result { notify(mallctl!("arena.0.decay")) }
-		set(&key, ())
+
+	pub fn flush() -> Result { super::notify(&mallctl!("thread.tcache.flush")) }
+
+	pub fn set_muzzy_decay(decay_ms: isize) -> Result<isize> {
+		set(mallctl!("arena.0.muzzy_decay_ms"), decay_ms)
 	}
 
-	pub fn decay() -> Result {
+	pub fn get_muzzy_decay() -> Result<isize> { get(mallctl!("arena.0.muzzy_decay_ms")) }
-		let mut key = mallctl!("arena.0.decay");
+
-		key[1] = arena_id()?.try_into()?;
+	pub fn set_dirty_decay(decay_ms: isize) -> Result<isize> {
-		set(&key, ())
+		set(mallctl!("arena.0.dirty_decay_ms"), decay_ms)
 	}
 
-	pub fn cache(enable: bool) -> Result {
+	pub fn get_dirty_decay() -> Result<isize> { get(mallctl!("arena.0.dirty_decay_ms")) }
-		set(&mallctl!("thread.tcache.enabled"), u8::from(enable))
+
+	pub fn enable_cache(enable: bool) -> Result<bool> {
+		super::set::<u8>(&mallctl!("thread.tcache.enabled"), enable.into()).map(is_nonzero!())
 	}
 
-	pub fn flush() -> Result { set(&mallctl!("thread.tcache.flush"), ()) }
+	pub fn is_cache_enabled() -> Result<bool> {
+		super::get::<u8>(&mallctl!("thread.tcache.enabled")).map(is_nonzero!())
+	}
 
-	pub fn allocated() -> Result<u64> { get::<u64>(&mallctl!("thread.allocated")) }
+	pub fn set_arena(id: usize) -> Result<usize> {
+		super::set::<u32>(&mallctl!("thread.arena"), id.try_into()?).and_then(math::try_into)
+	}
 
-	pub fn deallocated() -> Result<u64> { get::<u64>(&mallctl!("thread.deallocated")) }
+	pub fn arena_id() -> Result<usize> {
+		super::get::<u32>(&mallctl!("thread.arena")).and_then(math::try_into)
+	}
 
-	pub fn arena_id() -> Result<u32> { get::<u32>(&mallctl!("thread.arena")) }
+	pub fn allocated() -> Result<u64> { super::get(&mallctl!("thread.allocated")) }
+
+	pub fn deallocated() -> Result<u64> { super::get(&mallctl!("thread.deallocated")) }
+
+	fn notify(key: Key) -> Result { super::notify_by_arena(Some(arena_id()?), key) }
+
+	fn set<T>(key: Key, val: T) -> Result<T>
+	where
+		T: Copy + Debug,
+	{
+		super::set_by_arena(Some(arena_id()?), key, val)
+	}
+
+	fn get<T>(key: Key) -> Result<T>
+	where
+		T: Copy + Debug,
+	{
+		super::get_by_arena(Some(arena_id()?), key)
+	}
 }
 
-fn set<T>(key: &Key, val: T) -> Result
+pub fn trim<I: Into<Option<usize>>>(arena: I) -> Result {
+	notify_by_arena(arena.into(), mallctl!("arena.4096.purge"))
+}
+
+pub fn decay<I: Into<Option<usize>>>(arena: I) -> Result {
+	notify_by_arena(arena.into(), mallctl!("arena.4096.decay"))
+}
+
+pub fn set_muzzy_decay<I: Into<Option<usize>>>(arena: I, decay_ms: isize) -> Result<isize> {
+	if let Some(arena) = arena.into() {
+		set_by_arena(Some(arena), mallctl!("arena.4096.muzzy_decay_ms"), decay_ms)
+	} else {
+		set(&mallctl!("arenas.muzzy_decay_ms"), decay_ms)
+	}
+}
+
+pub fn set_dirty_decay<I: Into<Option<usize>>>(arena: I, decay_ms: isize) -> Result<isize> {
+	if let Some(arena) = arena.into() {
+		set_by_arena(Some(arena), mallctl!("arena.4096.dirty_decay_ms"), decay_ms)
+	} else {
+		set(&mallctl!("arenas.dirty_decay_ms"), decay_ms)
+	}
+}
+
+#[inline]
+#[must_use]
+pub fn is_affine_arena() -> bool { is_percpu_arena() || is_phycpu_arena() }
+
+#[inline]
+#[must_use]
+pub fn is_percpu_arena() -> bool { percpu_arenas().is_ok_and(is_equal_to!("percpu")) }
+
+#[inline]
+#[must_use]
+pub fn is_phycpu_arena() -> bool { percpu_arenas().is_ok_and(is_equal_to!("phycpu")) }
+
+pub fn percpu_arenas() -> Result<&'static str> {
+	let ptr = get::<*const c_char>(&mallctl!("opt.percpu_arena"))?;
+	//SAFETY: ptr points to a null-terminated string returned for opt.percpu_arena.
+	let cstr = unsafe { CStr::from_ptr(ptr) };
+	cstr.to_str().map_err(Into::into)
+}
+
+pub fn arenas() -> Result<usize> {
+	get::<u32>(&mallctl!("arenas.narenas")).and_then(math::try_into)
+}
+
+pub fn inc_epoch() -> Result<u64> { xchg(&mallctl!("epoch"), 1_u64) }
+
+pub fn acq_epoch() -> Result<u64> { xchg(&mallctl!("epoch"), 0_u64) }
+
+fn notify_by_arena(id: Option<usize>, mut key: Key) -> Result {
+	key[1] = id.unwrap_or(4096);
+	notify(&key)
+}
+
+fn set_by_arena<T>(id: Option<usize>, mut key: Key, val: T) -> Result<T>
 where
 	T: Copy + Debug,
 {
-	// SAFETY: T must be the exact expected type.
+	key[1] = id.unwrap_or(4096);
-	unsafe { mallctl::raw::write_mib(key.as_slice(), val) }.map_err(map_err)
+	set(&key, val)
+}
+
+fn get_by_arena<T>(id: Option<usize>, mut key: Key) -> Result<T>
+where
+	T: Copy + Debug,
+{
+	key[1] = id.unwrap_or(4096);
+	get(&key)
+}
+
+fn notify(key: &Key) -> Result { xchg(key, ()) }
+
+fn set<T>(key: &Key, val: T) -> Result<T>
+where
+	T: Copy + Debug,
+{
+	let _lock = CONTROL.write()?;
+	let res = xchg(key, val)?;
+	inc_epoch()?;
+
+	Ok(res)
 }
 
 fn get<T>(key: &Key) -> Result<T>
 where
 	T: Copy + Debug,
 {
+	acq_epoch()?;
+	acq_epoch()?;
+
 	// SAFETY: T must be perfectly valid to receive value.
 	unsafe { mallctl::raw::read_mib(key.as_slice()) }.map_err(map_err)
 }
 
+fn xchg<T>(key: &Key, val: T) -> Result<T>
+where
+	T: Copy + Debug,
+{
+	// SAFETY: T must be the exact expected type.
+	unsafe { mallctl::raw::update_mib(key.as_slice(), val) }.map_err(map_err)
+}
+
 fn key(name: &str) -> Result<Key> {
 	// tikv asserts the output buffer length is tight to the number of required mibs
 	// so we slice that down here.

src/database/pool.rs

@@ -13,7 +13,7 @@ use std::{
 use async_channel::{QueueStrategy, Receiver, RecvError, Sender};
 use conduwuit::{
 	debug, debug_warn, err, error, implement,
-	result::DebugInspect,
+	result::{DebugInspect, LogDebugErr},
 	trace,
 	utils::sys::compute::{get_affinity, nth_core_available, set_affinity},
 	Error, Result, Server,
@@ -289,6 +289,20 @@ fn worker_init(&self, id: usize) {
 
 	// affinity is empty (no-op) if there's only one queue
 	set_affinity(affinity.clone());
+
+	#[cfg(feature = "jemalloc")]
+	if affinity.clone().count() == 1 && conduwuit::alloc::je::is_affine_arena() {
+		use conduwuit::alloc::je::this_thread::{arena_id, set_arena};
+
+		let id = affinity.clone().next().expect("at least one id");
+
+		if let Ok(arena) = arena_id() {
+			if arena != id {
+				set_arena(id).log_debug_err().ok();
+			}
+		}
+	}
+
 	debug!(
 		?group,
 		affinity = ?affinity.collect::<Vec<_>>(),

src/main/Cargo.toml

@@ -41,6 +41,7 @@ default = [
 	"gzip_compression",
 	"io_uring",
 	"jemalloc",
+	"jemalloc_conf",
 	"media_thumbnail",
 	"release_max_log_level",
 	"systemd",
@@ -85,6 +86,9 @@ jemalloc_prof = [
 jemalloc_stats = [
 	"conduwuit-core/jemalloc_stats",
 ]
+jemalloc_conf = [
+	"conduwuit-core/jemalloc_conf",
+]
 media_thumbnail = [
 	"conduwuit-service/media_thumbnail",
 ]

src/main/clap.rs

@@ -92,6 +92,22 @@ pub(crate) struct Args {
 		require_equals(false),
 	)]
 	pub(crate) gc_on_park: Option<bool>,
+
+	/// Toggles muzzy decay for jemalloc arenas associated with a tokio
+	/// worker (when worker-affinity is enabled). Setting to false releases
+	/// memory to the operating system using MADV_FREE without MADV_DONTNEED.
+	/// Setting to false increases performance by reducing pagefaults, but
+	/// resident memory usage appears high until there is memory pressure. The
+	/// default is true unless the system has four or more cores.
+	#[arg(
+		long,
+		hide(true),
+		env = "CONDUWUIT_RUNTIME_GC_MUZZY",
+		action = ArgAction::Set,
+		num_args = 0..=1,
+		require_equals(false),
+	)]
+	pub(crate) gc_muzzy: Option<bool>,
 }
 
 /// Parse commandline arguments into structured data

src/main/runtime.rs

@@ -9,8 +9,12 @@ use std::{
 };
 
 use conduwuit::{
-	result::LogErr,
+	is_true,
-	utils::sys::compute::{nth_core_available, set_affinity},
+	result::LogDebugErr,
+	utils::{
+		available_parallelism,
+		sys::compute::{nth_core_available, set_affinity},
+	},
 	Result,
 };
 use tokio::runtime::Builder;
@@ -21,9 +25,11 @@ const WORKER_NAME: &str = "conduwuit:worker";
 const WORKER_MIN: usize = 2;
 const WORKER_KEEPALIVE: u64 = 36;
 const MAX_BLOCKING_THREADS: usize = 1024;
+const DISABLE_MUZZY_THRESHOLD: usize = 4;
 
 static WORKER_AFFINITY: OnceLock<bool> = OnceLock::new();
 static GC_ON_PARK: OnceLock<Option<bool>> = OnceLock::new();
+static GC_MUZZY: OnceLock<Option<bool>> = OnceLock::new();
 
 pub(super) fn new(args: &Args) -> Result<tokio::runtime::Runtime> {
 	WORKER_AFFINITY
@@ -34,6 +40,10 @@ pub(super) fn new(args: &Args) -> Result<tokio::runtime::Runtime> {
 		.set(args.gc_on_park)
 		.expect("set GC_ON_PARK from program argument");
 
+	GC_MUZZY
+		.set(args.gc_muzzy)
+		.expect("set GC_MUZZY from program argument");
+
 	let mut builder = Builder::new_multi_thread();
 	builder
 		.enable_io()
@@ -83,11 +93,13 @@ fn enable_histogram(builder: &mut Builder, args: &Args) {
 	),
 )]
 fn thread_start() {
-	if WORKER_AFFINITY
+	debug_assert_eq!(
-		.get()
+		Some(WORKER_NAME),
-		.copied()
+		thread::current().name(),
-		.expect("WORKER_AFFINITY initialized by runtime::new()")
+		"tokio worker name mismatch at thread start"
-	{
+	);
+
+	if WORKER_AFFINITY.get().is_some_and(is_true!()) {
 		set_worker_affinity();
 	}
 }
@@ -95,10 +107,6 @@ fn thread_start() {
 fn set_worker_affinity() {
 	static CORES_OCCUPIED: AtomicUsize = AtomicUsize::new(0);
 
-	if thread::current().name() != Some(WORKER_NAME) {
-		return;
-	}
-
 	let handle = tokio::runtime::Handle::current();
 	let num_workers = handle.metrics().num_workers();
 	let i = CORES_OCCUPIED.fetch_add(1, Ordering::Relaxed);
@@ -111,8 +119,33 @@ fn set_worker_affinity() {
 	};
 
 	set_affinity(once(id));
+	set_worker_mallctl(id);
 }
 
+#[cfg(feature = "jemalloc")]
+fn set_worker_mallctl(id: usize) {
+	use conduwuit::alloc::je::{
+		is_affine_arena,
+		this_thread::{set_arena, set_muzzy_decay},
+	};
+
+	if is_affine_arena() {
+		set_arena(id).log_debug_err().ok();
+	}
+
+	let muzzy_option = GC_MUZZY
+		.get()
+		.expect("GC_MUZZY initialized by runtime::new()");
+
+	let muzzy_auto_disable = available_parallelism() >= DISABLE_MUZZY_THRESHOLD;
+	if matches!(muzzy_option, Some(false) | None if muzzy_auto_disable) {
+		set_muzzy_decay(-1).log_debug_err().ok();
+	}
+}
+
+#[cfg(not(feature = "jemalloc"))]
+fn set_worker_mallctl(_: usize) {}
+
 #[tracing::instrument(
 	name = "join",
 	level = "debug",
@@ -157,7 +190,9 @@ fn thread_park() {
 
 fn gc_on_park() {
 	#[cfg(feature = "jemalloc")]
-	conduwuit::alloc::je::this_thread::decay().log_err().ok();
+	conduwuit::alloc::je::this_thread::decay()
+		.log_debug_err()
+		.ok();
 }
 
 #[cfg(tokio_unstable)]