From e480aaf338e3dfa280f0a78921c024265c811458 Mon Sep 17 00:00:00 2001
From: Alex Auvolat <alex@adnab.me>
Date: Tue, 15 Mar 2022 12:31:23 +0100
Subject: [PATCH] Make background tranquility a configurable parameter

---
 src/block/manager.rs | 11 ++++++-----
 src/block/rc.rs      |  8 +++-----
 src/model/garage.rs  | 15 +++++++++------
 src/util/config.rs   |  7 +++++++
 4 files changed, 25 insertions(+), 16 deletions(-)

diff --git a/src/block/manager.rs b/src/block/manager.rs
index feb6fb9d..3215d27e 100644
--- a/src/block/manager.rs
+++ b/src/block/manager.rs
@@ -29,15 +29,13 @@ use garage_rpc::*;
 
 use garage_table::replication::{TableReplication, TableShardedReplication};
 
-use crate::metrics::*;
 use crate::block::*;
+use crate::metrics::*;
 use crate::rc::*;
 
 /// Size under which data will be stored inlined in database instead of as files
 pub const INLINE_THRESHOLD: usize = 3072;
 
-pub const BACKGROUND_TRANQUILITY: u32 = 2;
-
 // Timeout for RPCs that read and write blocks to remote nodes
 const BLOCK_RW_TIMEOUT: Duration = Duration::from_secs(30);
 // Timeout for RPCs that ask other nodes whether they need a copy
@@ -82,8 +80,9 @@ pub struct BlockManager {
 	pub replication: TableShardedReplication,
 	/// Directory in which block are stored
 	pub data_dir: PathBuf,
-	/// Zstd compression level
+
 	compression_level: Option<i32>,
+	background_tranquility: u32,
 
 	mutation_lock: Mutex<BlockManagerLocked>,
 
@@ -109,6 +108,7 @@ impl BlockManager {
 		db: &sled::Db,
 		data_dir: PathBuf,
 		compression_level: Option<i32>,
+		background_tranquility: u32,
 		replication: TableShardedReplication,
 		system: Arc<System>,
 	) -> Arc<Self> {
@@ -139,6 +139,7 @@ impl BlockManager {
 			replication,
 			data_dir,
 			compression_level,
+			background_tranquility,
 			mutation_lock: Mutex::new(manager_locked),
 			rc,
 			resync_queue,
@@ -440,7 +441,7 @@ impl BlockManager {
 		while !*must_exit.borrow() {
 			match self.resync_iter(&mut must_exit).await {
 				Ok(true) => {
-					tranquilizer.tranquilize(BACKGROUND_TRANQUILITY).await;
+					tranquilizer.tranquilize(self.background_tranquility).await;
 				}
 				Ok(false) => {
 					tranquilizer.reset();
diff --git a/src/block/rc.rs b/src/block/rc.rs
index 0f497c9b..ec3ea44e 100644
--- a/src/block/rc.rs
+++ b/src/block/rc.rs
@@ -1,7 +1,7 @@
 use std::convert::TryInto;
 
-use garage_util::error::*;
 use garage_util::data::*;
+use garage_util::error::*;
 use garage_util::time::*;
 
 use crate::manager::BLOCK_GC_DELAY;
@@ -12,9 +12,7 @@ pub struct BlockRc {
 
 impl BlockRc {
 	pub(crate) fn new(rc: sled::Tree) -> Self {
-		Self {
-			rc
-		}
+		Self { rc }
 	}
 
 	/// Increment the reference counter associated to a hash.
@@ -34,7 +32,7 @@ impl BlockRc {
 			.rc
 			.update_and_fetch(&hash, |old| RcEntry::parse_opt(old).decrement().serialize())?;
 		let new_rc = RcEntry::parse_opt(new_rc);
-		Ok(matches!(new_rc, RcEntry::Deletable {..}))
+		Ok(matches!(new_rc, RcEntry::Deletable { .. }))
 	}
 
 	/// Read a block's reference count
diff --git a/src/model/garage.rs b/src/model/garage.rs
index 93402ca2..cbceeb64 100644
--- a/src/model/garage.rs
+++ b/src/model/garage.rs
@@ -7,11 +7,11 @@ use garage_util::config::*;
 
 use garage_rpc::system::System;
 
+use garage_block::manager::*;
 use garage_table::replication::ReplicationMode;
 use garage_table::replication::TableFullReplication;
 use garage_table::replication::TableShardedReplication;
 use garage_table::*;
-use garage_block::manager::*;
 
 use crate::block_ref_table::*;
 use crate::bucket_alias_table::*;
@@ -86,11 +86,14 @@ impl Garage {
 		};
 
 		info!("Initialize block manager...");
-		let block_manager =
-			BlockManager::new(&db,
-							  config.data_dir.clone(),
-							  config.compression_level,
-							  data_rep_param, system.clone());
+		let block_manager = BlockManager::new(
+			&db,
+			config.data_dir.clone(),
+			config.compression_level,
+			config.block_manager_background_tranquility,
+			data_rep_param,
+			system.clone(),
+		);
 
 		info!("Initialize block_ref_table...");
 		let block_ref_table = Table::new(
diff --git a/src/util/config.rs b/src/util/config.rs
index f74a62d0..e4d96476 100644
--- a/src/util/config.rs
+++ b/src/util/config.rs
@@ -23,6 +23,10 @@ pub struct Config {
 	#[serde(default = "default_block_size")]
 	pub block_size: usize,
 
+	/// Size of data blocks to save to disk
+	#[serde(default = "default_block_manager_background_tranquility")]
+	pub block_manager_background_tranquility: u32,
+
 	/// Replication mode. Supported values:
 	/// - none, 1 -> no replication
 	/// - 2 -> 2-way replication
@@ -118,6 +122,9 @@ fn default_sled_flush_every_ms() -> u64 {
 fn default_block_size() -> usize {
 	1048576
 }
+fn default_block_manager_background_tranquility() -> u32 {
+	2
+}
 
 /// Read and parse configuration
 pub fn read_config(config_file: PathBuf) -> Result<Config, Error> {