v0.34.0_1

src/cache/dashboard.rs

@@ -176,8 +176,7 @@ impl Cache {
         if let Some(revision) = revision {
             store.revision = revision;
             self.revision.store(revision, Ordering::Relaxed);
-            store.domains.clear();
-            store.domain_count = 0;
+            self.domain_stats.clear();
         }
         drop(store);
         self.cancel_all_fill_flights();
@@ -264,44 +263,24 @@ impl Cache {
         view
     }
     pub fn record(&self, scope: &str, domain: &str, outcome: &str, reason: &'static str) {
-        let mut store = self.store.lock().unwrap_or_else(|e| e.into_inner());
-        if let Some(c) = store.domain(scope, domain) {
-            match outcome {
-                "HIT" => c.hits += 1,
-                "MISS" => c.misses += 1,
-                _ => c.bypasses += 1,
-            }
-            if let Some(count) = c.reasons.get_mut(reason) {
-                *count = count.saturating_add(1);
-            } else {
-                c.reasons.insert(reason.to_owned(), 1);
-            }
-        }
+        self.domain_stats.record(scope, domain, outcome, reason);
     }
     pub fn record_reason(&self, scope: &str, domain: &str, reason: &'static str) {
-        let mut store = self.store.lock().unwrap_or_else(|e| e.into_inner());
-        if let Some(c) = store.domain(scope, domain) {
-            if let Some(count) = c.reasons.get_mut(reason) {
-                *count = count.saturating_add(1);
-            } else {
-                c.reasons.insert(reason.to_owned(), 1);
-            }
-        }
+        self.domain_stats.record_reason(scope, domain, reason);
     }
     pub fn dashboard(&self, scope: Option<&str>, offset: usize, limit: usize) -> Dashboard {
         let mut store = self.store.lock().unwrap_or_else(|e| e.into_inner());
         let revision = store.revision;
-        let mut groups: BTreeMap<(String, String), DomainView> = store
-            .domains
-            .iter()
-            .filter(|(vhost, _)| scope.is_none_or(|s| s == vhost.as_str()))
-            .flat_map(|(vhost, domains)| domains.iter().map(move |(domain, counters)| (vhost, domain, counters)))
-            .map(|(vhost, domain, counters)| {
+        let mut groups: BTreeMap<(String, String), DomainView> = self
+            .domain_stats
+            .snapshot(scope)
+            .into_iter()
+            .map(|((vhost, domain), counters)| {
                 (
                     (vhost.clone(), domain.clone()),
                     DomainView {
-                        vhost: vhost.clone(),
-                        domain: domain.clone(),
+                        vhost,
+                        domain,
                         entries: 0,
                         logical_bytes: 0,
                         resident_bytes: 0,
@@ -313,7 +292,7 @@ impl Cache {
                         } else {
                             0.0
                         },
-                        counters: counters.clone(),
+                        counters,
                     },
                 )
             })

src/cache/lifecycle.rs

@@ -6,6 +6,7 @@ impl Cache {
                 ..Default::default()
             })),
             revision: AtomicU64::new(revision),
+            domain_stats: DomainStatsStore::default(),
             cold: Arc::new(Mutex::new(ColdStore::default())),
             tier_settings: Mutex::new(Settings::default()),
             scope_revisions: Mutex::new(HashMap::new()),
@@ -57,6 +58,7 @@ impl Cache {
                 ..Default::default()
             })),
             revision: AtomicU64::new(revision),
+            domain_stats: DomainStatsStore::default(),
             cold: Arc::new(Mutex::new(ColdStore::default())),
             tier_settings: Mutex::new(settings),
             scope_revisions: Mutex::new(scope_revisions),

src/cache/lookup/hot.rs

@@ -61,7 +61,6 @@ impl Cache {
                 store.lru.insert(sequence, storage_key);
                 // Preserve the exact LRU and domain-byte counters, without
                 // allocating a replacement variant index or String keys.
-                store.saved_body_hit(&ticket.scope, &ticket.domain, body_bytes);
                 self.counters.hits.fetch_add(1, Ordering::Relaxed);
                 drop(store);
 
@@ -77,6 +76,7 @@ impl Cache {
                     "age",
                     HeaderValue::from_str(&age.to_string()).expect("integer header"),
                 );
+                self.domain_stats.saved_body_hit(&ticket.scope, &ticket.domain, body_bytes);
                 return Some(Hit {
                     response,
                     body,
@@ -274,12 +274,7 @@ impl Cache {
             "age",
             HeaderValue::from_str(&age.to_string()).expect("integer header"),
         );
-        {
-            let mut store = self.store.lock().unwrap_or_else(|e| e.into_inner());
-            if let Some(c) = store.domain(&ticket.scope, &ticket.domain) {
-                c.saved_body_bytes = c.saved_body_bytes.saturating_add(entry.body_bytes as u64);
-            }
-        }
+        self.domain_stats.saved_body_hit(&ticket.scope, &ticket.domain, entry.body_bytes);
         self.counters.hits.fetch_add(1, Ordering::Relaxed);
         self.counters.cold_hits.fetch_add(1, Ordering::Relaxed);
         self.counters

src/cache/lookup/insert.rs

@@ -108,9 +108,7 @@ impl Cache {
             return false;
         }
         if count_stored {
-            if let Some(c) = store.domain(&entry.scope, &entry.domain) {
-                c.stored += 1;
-            }
+            self.domain_stats.stored(&entry.scope, &entry.domain);
         }
         entry.last_access = Instant::now();
         entry.sequence = store.next_sequence();

src/cache/mod.rs

@@ -5,6 +5,7 @@
 //! policy and streaming-fill code can be reviewed independently.
 
 include!("model.rs");
+include!("stats.rs");
 include!("lifecycle.rs");
 include!("cold.rs");
 include!("dashboard.rs");

src/cache/model/cache.rs

@@ -336,8 +336,6 @@ struct Store {
     control_revision: u64,
     scope_generations: HashMap<String, u64>,
     key_generations: HashMap<Key, u64>,
-    domains: BTreeMap<String, BTreeMap<String, DomainCounters>>,
-    domain_count: usize,
 }
 impl Store {
     fn index_variant(&mut self, base_key: Key, key: Key) {
@@ -362,26 +360,6 @@ impl Store {
         }
         Some(entry)
     }
-    fn domain(&mut self, scope: &str, domain: &str) -> Option<&mut DomainCounters> {
-        // The common path is a borrowed lookup: no allocation of scope/domain
-        // strings for every cache hit or log-reason counter update.
-        if self.domains.get(scope).is_some_and(|d| d.contains_key(domain)) {
-            return self.domains.get_mut(scope)?.get_mut(domain);
-        }
-        if self.domain_count >= 4096 {
-            return None;
-        }
-        self.domain_count += 1;
-        Some(self.domains.entry(scope.to_owned()).or_default()
-            .entry(domain.to_owned()).or_default())
-    }
-    fn saved_body_hit(&mut self, scope: &str, domain: &str, bytes: usize) {
-        // Every admitted HOT insertion registered its domain. If the bounded
-        // stats table is full, skip accounting for an unregistered domain.
-        if let Some(c) = self.domains.get_mut(scope).and_then(|d| d.get_mut(domain)) {
-            c.saved_body_bytes = c.saved_body_bytes.saturating_add(bytes as u64);
-        }
-    }
     fn next_sequence(&mut self) -> u64 {
         // No practical wrapping, but a wrap must not corrupt LRU bookkeeping.
         if self.sequence == u64::MAX {

src/cache/model/maintenance.rs

@@ -52,6 +52,7 @@ impl Drop for TransientLeaseInner {
 
 pub struct Cache {
     store: Arc<Mutex<Store>>,
+    domain_stats: DomainStatsStore,
     revision: AtomicU64,
     cold: Arc<Mutex<ColdStore>>,
     tier_settings: Mutex<Settings>,

src/cache/stats.rs

@@ -0,0 +1,187 @@
+// Lock-free read path for bounded, per-domain cache dashboard counters.
+//
+// Cache-disabled proxy requests still contribute to BYPASS and reason totals,
+// but must never lock the HOT object/LRU store. Published domain/reason indexes
+// are immutable; individual counters are atomics. Only first sight of a new
+// domain/reason acquires the registration mutex.
+
+use arc_swap::ArcSwap;
+
+const DOMAIN_STATS_LIMIT: usize = 4096;
+const FAST_REASONS: [&str; 4] = ["cache_disabled", "cache_hit", "cache_miss", "request_cookie"];
+
+type ReasonIndex = BTreeMap<&'static str, Arc<AtomicU64>>;
+type DomainIndex = BTreeMap<String, BTreeMap<String, Arc<DomainStats>>>;
+
+#[derive(Clone, Default)]
+struct PublishedDomains {
+    index: DomainIndex,
+    count: usize,
+}
+
+struct DomainStats {
+    hits: AtomicU64,
+    misses: AtomicU64,
+    bypasses: AtomicU64,
+    stored: AtomicU64,
+    saved_body_bytes: AtomicU64,
+    fast_reasons: [AtomicU64; FAST_REASONS.len()],
+    reasons: ArcSwap<ReasonIndex>,
+    register_reason: Mutex<()>,
+}
+
+impl Default for DomainStats {
+    fn default() -> Self {
+        Self {
+            hits: AtomicU64::new(0),
+            misses: AtomicU64::new(0),
+            bypasses: AtomicU64::new(0),
+            stored: AtomicU64::new(0),
+            saved_body_bytes: AtomicU64::new(0),
+            fast_reasons: std::array::from_fn(|_| AtomicU64::new(0)),
+            reasons: ArcSwap::from_pointee(ReasonIndex::new()),
+            register_reason: Mutex::new(()),
+        }
+    }
+}
+
+impl DomainStats {
+    fn record(&self, outcome: &str, reason: &'static str) {
+        match outcome {
+            "HIT" => &self.hits,
+            "MISS" => &self.misses,
+            _ => &self.bypasses,
+        }.fetch_add(1, Ordering::Relaxed);
+        self.record_reason(reason);
+    }
+
+    fn record_reason(&self, reason: &'static str) {
+        // Cache OFF is the highest-volume case; avoid reason map lookup and
+        // any shared lock/allocator activity for its dashboard reason.
+        if let Some(index) = FAST_REASONS.iter().position(|label| *label == reason) {
+            self.fast_reasons[index].fetch_add(1, Ordering::Relaxed);
+            return;
+        }
+        let published = self.reasons.load();
+        if let Some(counter) = published.get(reason) {
+            counter.fetch_add(1, Ordering::Relaxed);
+            return;
+        }
+        drop(published);
+        let _guard = self.register_reason.lock().unwrap_or_else(|e| e.into_inner());
+        let published = self.reasons.load_full();
+        if let Some(counter) = published.get(reason) {
+            counter.fetch_add(1, Ordering::Relaxed);
+            return;
+        }
+        let mut next = (*published).clone();
+        next.insert(reason, Arc::new(AtomicU64::new(1)));
+        self.reasons.store(Arc::new(next));
+    }
+
+    fn snapshot(&self) -> DomainCounters {
+        let load = |value: &AtomicU64| value.load(Ordering::Relaxed);
+        let mut reasons = BTreeMap::new();
+        for (label, counter) in FAST_REASONS.iter().zip(&self.fast_reasons) {
+            let value = load(counter);
+            if value > 0 {
+                reasons.insert((*label).to_owned(), value);
+            }
+        }
+        for (label, counter) in self.reasons.load().iter() {
+            reasons.insert((*label).to_owned(), load(counter));
+        }
+        DomainCounters {
+            hits: load(&self.hits),
+            misses: load(&self.misses),
+            bypasses: load(&self.bypasses),
+            stored: load(&self.stored),
+            saved_body_bytes: load(&self.saved_body_bytes),
+            reasons,
+        }
+    }
+}
+
+struct DomainStatsStore {
+    domains: ArcSwap<PublishedDomains>,
+    register: Mutex<()>,
+}
+
+impl Default for DomainStatsStore {
+    fn default() -> Self {
+        Self {
+            domains: ArcSwap::from_pointee(PublishedDomains::default()),
+            register: Mutex::new(()),
+        }
+    }
+}
+
+impl DomainStatsStore {
+    fn with(&self, scope: &str, domain: &str, action: impl FnOnce(&DomainStats)) {
+        let published = self.domains.load();
+        if let Some(counters) = published.index.get(scope).and_then(|hosts| hosts.get(domain)) {
+            action(counters);
+            return;
+        }
+        drop(published);
+        // Rare path: register only 4096 distinct (scope, domain) pairs. The
+        // published map is cloned on first insertion, never on a request hit.
+        let _guard = self.register.lock().unwrap_or_else(|e| e.into_inner());
+        let published = self.domains.load_full();
+        if let Some(counters) = published.index.get(scope).and_then(|hosts| hosts.get(domain)) {
+            action(counters);
+            return;
+        }
+        if published.count >= DOMAIN_STATS_LIMIT {
+            return;
+        }
+        let mut next = (*published).clone();
+        let counters = Arc::new(DomainStats::default());
+        next.index.entry(scope.to_owned()).or_default()
+            .insert(domain.to_owned(), Arc::clone(&counters));
+        next.count += 1;
+        self.domains.store(Arc::new(next));
+        action(&counters);
+    }
+
+    fn record(&self, scope: &str, domain: &str, outcome: &str, reason: &'static str) {
+        self.with(scope, domain, |counters| counters.record(outcome, reason));
+    }
+
+    fn record_reason(&self, scope: &str, domain: &str, reason: &'static str) {
+        self.with(scope, domain, |counters| counters.record_reason(reason));
+    }
+
+    fn stored(&self, scope: &str, domain: &str) {
+        self.with(scope, domain, |counters| {
+            counters.stored.fetch_add(1, Ordering::Relaxed);
+        });
+    }
+
+    fn saved_body_hit(&self, scope: &str, domain: &str, bytes: usize) {
+        // COLD entries loaded from persisted metadata may be served before a
+        // domain is registered. Preserve first-hit byte accounting as well.
+        self.with(scope, domain, |counters| {
+            counters.saved_body_bytes.fetch_add(bytes as u64, Ordering::Relaxed);
+        });
+    }
+
+    fn clear(&self) {
+        let _guard = self.register.lock().unwrap_or_else(|e| e.into_inner());
+        self.domains.store(Arc::new(PublishedDomains::default()));
+    }
+
+    fn snapshot(&self, scope: Option<&str>) -> BTreeMap<(String, String), DomainCounters> {
+        let published = self.domains.load();
+        let mut counters = BTreeMap::new();
+        for (vhost, domains) in &published.index {
+            if !scope.is_none_or(|selected| selected == vhost) {
+                continue;
+            }
+            for (domain, metric) in domains {
+                counters.insert((vhost.clone(), domain.clone()), metric.snapshot());
+            }
+        }
+        counters
+    }
+}

src/cache/tests/dashboard_tests.rs

@@ -215,6 +215,57 @@ mod dashboard_tests {
         }
     }
 
+    #[test]
+    fn cache_domain_metrics_do_not_lock_hot_store_and_preserve_reasons() {
+        let cache = Cache::new(7);
+        // A BYPASS must be recordable even while the HOT/LRU mutex is held.
+        let store = cache.store.lock().unwrap();
+        cache.record("alpha", "a.example", "BYPASS", "cache_disabled");
+        cache.record_reason("alpha", "a.example", "background_refresh_failure");
+        drop(store);
+        let workers = 8;
+        let each = 2000;
+        let mut tasks = Vec::new();
+        for _ in 0..workers {
+            let cache = Arc::clone(&cache);
+            tasks.push(std::thread::spawn(move || {
+                for _ in 0..each {
+                    cache.record("alpha", "a.example", "BYPASS", "cache_disabled");
+                    cache.record("alpha", "a.example", "HIT", "cache_hit");
+                }
+            }));
+        }
+        for task in tasks {
+            task.join().expect("domain counter worker");
+        }
+        let scoped = cache.dashboard(Some("alpha"), 0, 1);
+        assert_eq!(scoped.domains.len(), 1);
+        let counters = &scoped.domains[0].counters;
+        assert_eq!(counters.bypasses, 1 + workers * each);
+        assert_eq!(counters.hits, workers * each);
+        assert_eq!(counters.reasons["cache_disabled"], 1 + workers * each);
+        assert_eq!(counters.reasons["cache_hit"], workers * each);
+        assert_eq!(counters.reasons["background_refresh_failure"], 1);
+        assert_eq!(cache.purge_scope("alpha"), 0);
+        assert_eq!(cache.dashboard(Some("alpha"), 0, 1).domains[0].counters.hits, workers * each);
+        cache.purge(Some(8));
+        assert!(cache.dashboard(None, 0, 1).domains.is_empty());
+        cache.record("alpha", "a.example", "MISS", "cache_miss");
+        let after_reset = cache.dashboard(Some("alpha"), 0, 1);
+        assert_eq!(after_reset.domains[0].counters.misses, 1);
+        assert_eq!(after_reset.domains[0].counters.hits, 0);
+        assert_eq!(after_reset.statistics_revision, 8);
+    }
+
+    #[test]
+    fn first_hit_saved_bytes_registers_domain_even_without_prior_record() {
+        let cache = Cache::new(7);
+        cache.domain_stats.saved_body_hit("cold", "restored.example", 1040);
+        let result = cache.dashboard(Some("cold"), 0, 1);
+        assert_eq!(result.domains.len(), 1);
+        assert_eq!(result.domains[0].counters.saved_body_bytes, 1040);
+    }
+
     #[test]
     fn per_domain_counter_cardinality_is_bounded() {
         let cache = Cache::new(7);