daddbc926c
Root cause: unified_cache_refill() accessed cache->slots before initialization when a size class was first used via the refill path (not pop path). Fix: Add lazy initialization check at start of unified_cache_refill() - Check if cache->slots is NULL before accessing - Call unified_cache_init() if needed - Return NULL if init fails (graceful degradation) Also includes: - ss_cold_start_box.inc.h: Box Pattern for default prewarm settings - hakmem_super_registry.c: Use static array in prewarm (avoid recursion) - Default prewarm enabled (1 SuperSlab/class, configurable via ENV) Test: 8B→16B→Mixed allocation pattern now works correctly 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
119 lines
3.9 KiB
C
119 lines
3.9 KiB
C
// ss_cold_start_box.inc.h - SuperSlab Cold Start Protection
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// ==========================================================================
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//
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// Purpose: Prevent OOM on cold start by enabling minimal prewarm by default
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//
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// Problem:
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// - SuperSlab LRU cache starts empty
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// - First allocation triggers mmap() which may fail
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// - No prewarm by default = cold start OOM
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//
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// Solution (Box Pattern):
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// - Default: Prewarm 1 SuperSlab per class (minimal footprint: 8MB)
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// - ENV configurable: HAKMEM_SS_PREWARM_COUNT=N (0 to disable)
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// - Observable: Debug logging
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// - Inline: Zero runtime overhead for config access
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//
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// ENV Variables:
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// HAKMEM_SS_PREWARM_COUNT=N - SuperSlabs per class (default: 1)
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// HAKMEM_SS_PREWARM_DISABLE=1 - Disable prewarm entirely (legacy compat)
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//
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// Memory Impact:
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// Default (count=1): 8 classes * 1MB = 8MB
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// Aggressive (count=4): 8 classes * 4MB = 32MB
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//
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// ==========================================================================
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#ifndef HAK_SS_COLD_START_BOX_INC_H
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#define HAK_SS_COLD_START_BOX_INC_H
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#include <stdlib.h>
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#include <stdio.h> // For ss_cold_start_log_config()
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// ============================================================================
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// Configuration Constants
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// ============================================================================
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// Default prewarm count per class (minimal cold start protection)
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// Phase 11+: Fixed malloc() recursion by using static array in hak_ss_prewarm_class()
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#define SS_COLD_START_DEFAULT_COUNT 1
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// Maximum prewarm count per class (safety cap)
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#define SS_COLD_START_MAX_COUNT 512
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// ============================================================================
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// Inline Configuration Helper
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// ============================================================================
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// Get cold start prewarm count (cached, ENV-configurable)
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//
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// Returns:
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// - 0 if disabled (HAKMEM_SS_PREWARM_DISABLE=1)
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// - N from HAKMEM_SS_PREWARM_COUNT=N if set
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// - SS_COLD_START_DEFAULT_COUNT (1) otherwise
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//
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// Thread-safe: uses static cache with simple atomic semantics
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//
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static inline int ss_cold_start_get_count(void) {
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static int g_cached = -1; // -1 = not initialized
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if (__builtin_expect(g_cached >= 0, 1)) {
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return g_cached; // Fast path: already cached
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}
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// Slow path: parse ENV
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// Check disable flag first
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const char* disable_env = getenv("HAKMEM_SS_PREWARM_DISABLE");
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if (disable_env && *disable_env && *disable_env != '0') {
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g_cached = 0; // Disabled
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return 0;
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}
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// Check custom count
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const char* count_env = getenv("HAKMEM_SS_PREWARM_COUNT");
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if (count_env && *count_env) {
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char* endptr;
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long count = strtol(count_env, &endptr, 10);
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if (*endptr == '\0' && count >= 0) {
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// Cap at max
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if (count > SS_COLD_START_MAX_COUNT) {
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count = SS_COLD_START_MAX_COUNT;
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}
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g_cached = (int)count;
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return g_cached;
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}
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// Invalid format - fall through to default
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}
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// Default: minimal prewarm enabled
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g_cached = SS_COLD_START_DEFAULT_COUNT;
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return g_cached;
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}
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// Check if cold start prewarm is enabled
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static inline int ss_cold_start_is_enabled(void) {
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return ss_cold_start_get_count() > 0;
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}
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// ============================================================================
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// Debug Helper
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// ============================================================================
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// Log cold start configuration (call from init for diagnostics)
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static inline void ss_cold_start_log_config(void) {
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#if !HAKMEM_BUILD_RELEASE
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int count = ss_cold_start_get_count();
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if (count > 0) {
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fprintf(stderr, "[SS_COLD_START] Enabled: %d SuperSlabs per class (total: %d MB)\n",
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count, count * 8); // 8 classes * 1MB
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} else {
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fprintf(stderr, "[SS_COLD_START] Disabled\n");
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}
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#else
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(void)0; // No-op in release mode
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#endif
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}
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#endif // HAK_SS_COLD_START_BOX_INC_H
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