ANVIL Memory Troubleshooting — Mac Studio

ANVIL Memory Troubleshooting — Mac Studio (M2 Ultra 192GB)

Incident Summary

Date: 2026-04-20
Symptom: System freezes, Chrome/Claude unresponsive, OOM kernel panics
Root Cause: Zombie Ollama runner processes + duplicate launchd agents + runaway grep processes
Resolution: Ollama config tuning, duplicate agent removal, zombie cleanup daemon, Ollama 0.21.0 upgrade

Root Causes

Ollama zombie runners: ollama ps reports 0 models loaded, but pgrep -fl ollama_llama_server shows 4-6 GB processes still resident
Duplicate launchd agents: Both com.alai.ollama-serve.plist and com.alai.ollama-serve-v2.plist running simultaneously → 2x Ollama daemons
grep memory leak: grep -rn commands on large codebases hang and consume 8+ GB RAM each
Preload warmup bloat: com.john.ollama-warmup.plist loading 3 models on boot → 48 GB baseline before any work

Permanent Fix — Ollama Config

File: ~/Library/LaunchAgents/com.alai.ollama-serve-v2.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key>
  <string>com.alai.ollama-serve-v2</string>
  <key>ProgramArguments</key>
  <array>
    <string>/usr/local/bin/ollama</string>
    <string>serve</string>
  </array>
  <key>EnvironmentVariables</key>
  <dict>
    <key>OLLAMA_HOST</key>
    <string>0.0.0.0:11434</string>
    <key>OLLAMA_KEEP_ALIVE</key>
    <string>60s</string>
    <key>OLLAMA_MAX_LOADED_MODELS</key>
    <string>1</string>
    <key>OLLAMA_NUM_PARALLEL</key>
    <string>1</string>
  </dict>
  <key>RunAtLoad</key>
  <true/>
  <key>KeepAlive</key>
  <true/>
  <key>StandardOutPath</key>
  <string>/tmp/ollama-serve.log</string>
  <key>StandardErrorPath</key>
  <string>/tmp/ollama-serve-error.log</string>
</dict>
</plist>

Key parameters:

OLLAMA_KEEP_ALIVE=60s — unload model after 60s idle (default 5m causes bloat)
OLLAMA_MAX_LOADED_MODELS=1 — only one model resident at a time
OLLAMA_NUM_PARALLEL=1 — no parallel inference (reduces contention)

Zombie Cleanup Daemon

File: ~/Library/LaunchAgents/com.alai.zombie-cleanup.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key>
  <string>com.alai.zombie-cleanup</string>
  <key>ProgramArguments</key>
  <array>
    <string>/bin/bash</string>
    <string>/Users/makinja/system/tools/zombie-proc-cleanup.sh</string>
  </array>
  <key>StartInterval</key>
  <integer>3600</integer>
  <key>StandardOutPath</key>
  <string>/tmp/zombie-cleanup.log</string>
</dict>
</plist>

Script: ~/system/tools/zombie-proc-cleanup.sh

#!/bin/bash
# Kill zombie Ollama runners (no parent process or disconnected from ollama serve)
pgrep -fl ollama_llama_server | while read -r pid rest; do
  parent=$(ps -o ppid= -p "$pid" | xargs)
  if [[ -z "$parent" ]] || ! ps -p "$parent" | grep -q ollama; then
    echo "$(date): Killing zombie Ollama runner $pid"
    kill -9 "$pid"
  fi
done

# Kill grep processes older than 5 minutes (likely hung)
ps -eo pid,etime,command | grep 'grep -rn' | while read -r pid etime rest; do
  minutes=$(echo "$etime" | awk -F: '{print ($1*60)+$2}')
  if [[ "$minutes" -gt 5 ]]; then
    echo "$(date): Killing hung grep process $pid (runtime: $etime)"
    kill -9 "$pid"
  fi
done

Disabled Agents

launchctl unload ~/Library/LaunchAgents/com.alai.ollama-serve.plist
launchctl unload ~/Library/LaunchAgents/com.john.ollama-warmup.plist
rm ~/Library/LaunchAgents/com.alai.ollama-serve.plist
rm ~/Library/LaunchAgents/com.john.ollama-warmup.plist

Ollama Upgrade

brew upgrade ollama  # 0.19.0 → 0.21.0
# Changelog: Fixed memory leak in runner cleanup (issue #4821)

OOM Symptom Recognition

Command:

vm_stat | awk '/Pages free/ {printf "%.1f GB\n", $3*16384/1024/1024/1024}'

Thresholds:

< 5 GB free: Alert — investigate top memory consumers
< 2 GB free: Critical — kill non-essential processes immediately
< 500 MB free: Imminent OOM — force quit Claude/Chrome, restart Ollama

Quick triage:

ps aux | sort -nrk 4 | head -10  # Top 10 memory hogs
pgrep -fl ollama_llama_server    # Zombie Ollama runners
pgrep -fl grep                    # Hung grep processes

Prevention Checklist

Monitor free RAM hourly: vm_stat check in cron
Zombie cleanup daemon running: launchctl list | grep zombie-cleanup
Only one Ollama launchd agent: launchctl list | grep ollama → expect 1 line
No warmup preload agents: launchctl list | grep warmup → empty
Grep with timeout: timeout 60 grep -rn ... instead of bare grep -rn