53 lines
1.7 KiB
C
53 lines
1.7 KiB
C
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// ss_os_acquire_box.h - SuperSlab OS Memory Acquisition Box
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// Purpose: Low-level OS memory allocation (mmap/munmap) for SuperSlabs
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// Box Theory: Encapsulates platform-specific aligned memory allocation
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//
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// Responsibilities:
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// - Aligned mmap allocation (2MB boundary)
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// - OOM diagnostics and error reporting
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// - Global mmap counters
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//
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// Dependencies: None (pure OS interface)
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//
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// License: MIT
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// Date: 2025-11-19
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#ifndef HAKMEM_SS_OS_ACQUIRE_BOX_H
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#define HAKMEM_SS_OS_ACQUIRE_BOX_H
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#include <stdint.h>
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#include <stddef.h>
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#include <stdatomic.h>
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// ============================================================================
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// Global Counters (for debugging/diagnostics)
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// ============================================================================
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extern _Atomic uint64_t g_ss_mmap_count;
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extern _Atomic uint64_t g_final_fallback_mmap_count;
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// ============================================================================
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// OS Acquisition API
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// ============================================================================
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// Acquire aligned SuperSlab memory from OS via mmap
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//
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// Parameters:
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// size_class: Size class index (0-7, for statistics)
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// ss_size: SuperSlab size in bytes (e.g., 2^21 = 2MB)
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// ss_mask: Alignment mask (ss_size - 1)
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// populate: If true, use MAP_POPULATE to prefault pages
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//
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// Returns: Aligned pointer or NULL on OOM
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//
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// Guarantees:
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// - Returns NULL on OOM (never crashes)
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// - Returned pointer is aligned to ss_size boundary
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// - Logs OOM once per process (not spammy)
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// - Updates g_ss_mmap_count counter
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//
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// Thread-safe: Yes (no shared state mutations except atomic counters)
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void* ss_os_acquire(uint8_t size_class, size_t ss_size, uintptr_t ss_mask, int populate);
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#endif // HAKMEM_SS_OS_ACQUIRE_BOX_H
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