[Verse 1] In the kernel's sacred space where programs cannot tread Virtual memory maps dissolve, physical chunks instead No malloc here to save you, no heap to call your own Just kmalloc and vmalloc in zones carved from silicon stone [Chorus] Kernel memory, never swapped away GFP flags decide if we sleep or stay DMA coherent, cache lines aligned Pages pinned forever in the kernel's mind No protection faults, no user games Physical addresses, direct domain claims [Verse 2] GFP_KERNEL sleeps when pressure builds too high GFP_ATOMIC never blocks, for interrupts that fly ZONE_DMA lives below sixteen megs of RAM Where ancient hardware speaks in addresses antiquated and cramped [Chorus] Kernel memory, never swapped away GFP flags decide if we sleep or stay DMA coherent, cache lines aligned Pages pinned forever in the kernel's mind No protection faults, no user games Physical addresses, direct domain claims [Bridge] kmem_cache creates slabs of identical size Buddy allocator merges blocks before your eyes While user space gets copy-on-write delays Kernel owns its pages for all of its days [Verse 3] DMA coherent memory shares with hardware's view Cache-coherent protocols keep both sides true No page faults permitted when interrupts arrive Every allocation must keep the system alive [Chorus] Kernel memory, never swapped away GFP flags decide if we sleep or stay DMA coherent, cache lines aligned Pages pinned forever in the kernel's mind No protection faults, no user games Physical addresses, direct domain claims [Outro] From bootmem's early gift to high memory's height Kernel space remembers what's wrong and what's right In zones and in pages, forever to stay Where silicon meets software every single day
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