From 5db12207dca369b98acdefc0f7ed33bd418b7794 Mon Sep 17 00:00:00 2001
From: Monthon Klongklaew <monthonk@amazon.com>
Date: Thu, 26 Sep 2024 09:10:55 +0000
Subject: [PATCH] Put the cli argument behind a feature flag

Signed-off-by: Monthon Klongklaew <monthonk@amazon.com>
---
 mountpoint-s3/Cargo.toml |  1 +
 mountpoint-s3/src/cli.rs | 20 ++++++++++++--------
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/mountpoint-s3/Cargo.toml b/mountpoint-s3/Cargo.toml
index 93868ad77..bc68fabce 100644
--- a/mountpoint-s3/Cargo.toml
+++ b/mountpoint-s3/Cargo.toml
@@ -82,6 +82,7 @@ built = { version = "0.7.1", features = ["git2"] }
 [features]
 # Unreleased feature flags
 event_log = []
+mem_limiter = []
 # Features for choosing tests
 fips_tests = []
 fuse_tests = []
diff --git a/mountpoint-s3/src/cli.rs b/mountpoint-s3/src/cli.rs
index 5cabc2871..1988d81c6 100644
--- a/mountpoint-s3/src/cli.rs
+++ b/mountpoint-s3/src/cli.rs
@@ -157,6 +157,8 @@ pub struct CliArgs {
     )]
     pub max_threads: u64,
 
+    // This config is still unstable
+    #[cfg(feature = "mem_limiter")]
     #[clap(
         long,
         help = "Maximum memory usage target [default: 95% of total system memory with a minimum of 512 MiB]",
@@ -743,14 +745,16 @@ where
     filesystem_config.allow_overwrite = args.allow_overwrite;
     filesystem_config.s3_personality = s3_personality;
     filesystem_config.server_side_encryption = ServerSideEncryption::new(args.sse, args.sse_kms_key_id);
-    filesystem_config.mem_limit = if let Some(max_mem_target) = args.max_memory_target {
-        max_mem_target * 1024 * 1024
-    } else {
-        const MINIMUM_MEM_LIMIT: u64 = 512 * 1024 * 1024;
-        let sys = System::new_with_specifics(RefreshKind::everything());
-        let default_mem_target = (sys.total_memory() as f64 * 0.95) as u64;
-        default_mem_target.max(MINIMUM_MEM_LIMIT)
-    };
+
+    const MINIMUM_MEM_LIMIT: u64 = 512 * 1024 * 1024;
+    let sys = System::new_with_specifics(RefreshKind::everything());
+    let default_mem_target = (sys.total_memory() as f64 * 0.95) as u64;
+    filesystem_config.mem_limit = default_mem_target.max(MINIMUM_MEM_LIMIT);
+
+    #[cfg(feature = "mem_limiter")]
+    if let Some(max_mem_target) = args.max_memory_target {
+        filesystem_config.mem_limit = max_mem_target * 1024 * 1024;
+    }
 
     // Written in this awkward way to force us to update it if we add new checksum types
     filesystem_config.use_upload_checksums = match args.upload_checksums {