Deep Dive — Study Catalog

Reference Books

Part I — System Boot & Initialization

ULK Ch.1 · LKD Ch.1

• §1.1Bootloader & U-Boot
• §1.2Kernel Boot Process (start_kernel → PID 1)

Part II — Memory Management

ULK Ch.2,8,9 · LKD Ch.12,15,16

• §2.1Physical Memory Layout (NUMA / Zones / struct page)
• §2.2Buddy Allocator
• §2.3Slab / Slub Allocator
• §2.4Virtual Memory & Paging (4-level PT, TLB, Huge Pages)
• §2.5Process Address Space (mm_struct, VMA, mmap, COW)
• §2.6Page Cache & Buffer Cache (LRU/MRU, writeback)
• §2.7Memory-Mapped I/O & DMA (ioremap, IOMMU)

Part III — Process Management & Scheduling

LKD Ch.3,4,5 · ULK Ch.3,6,11

• §3.1Process & Thread Data Structures (task_struct)
• §3.2Process Lifecycle (fork → exec → exit)
• §3.3CPU Scheduling (CFS, SCHED_FIFO, load balancing)
• §3.4Preemption & Context Switch
• §3.5Interrupts & Bottom Halves (IRQ → softirq → NAPI)
• §3.6Kernel Timers (jiffies, timer wheel, hrtimer, NO_HZ)
• §3.7Kernel Data Structures (list, hlist, rbtree, xarray, bitmap)

Part IV — System Calls & User-Kernel Interface

LKD Ch.5 · ULK Ch.10

• §4.1System Call Mechanism (syscall, vDSO)
• §4.2Key Networking Syscalls (socket, epoll, io_uring)
• §4.3ioctl & Netlink
• §4.4Sync / Async I/O (blocking, O_NONBLOCK, epoll, io_uring, sendfile)
• §4.5Signals

Part V — Interprocess Communication

LKD Ch.17 · ULK Ch.19

• §5.1Pipes & FIFOs
• §5.2POSIX IPC (msg queues, shared memory, semaphores)
• §5.3Futex (fast userspace mutex)
• §5.4Unix Domain Sockets

Part VI — Parallel Programming & Synchronization

PPH all · LKD Ch.9,10 · critical interview section

• §6.1Hardware Foundations (pipeline, store buffer, false sharing, NUMA)
• §6.2Cache Coherence Protocols (MESI / MOESI)
• §6.3Memory Barriers & Ordering (smp_mb, acquire/release, C11 model)
• §6.4Atomic Operations (CAS, fetch-add, ABA problem)
• §6.5Counting & Per-CPU Counters
• §6.6Locking Design Patterns (lockdep, ordering, granularity)
• §6.7Spinlock Internals (ticket → MCS → qspinlock)
• §6.8Sleeping Locks (mutex, rwsem, semaphore)
• §6.9Sequence Locks (seqlock_t)
• §6.10RCU Deep Dive (grace period, call_rcu, SRCU)
• §6.11Lock-Free & Wait-Free Algorithms (Treiber stack, MS queue, hazard ptrs)
• §6.12Per-CPU Data & Data Ownership
• §6.13Deferred Processing (refcount, RCU reclaim, workqueue)
• §6.14Parallel Design Patterns (batch, sharding, pipeline, map-reduce)
• §6.15Debugging (lockdep, KCSAN, TSan, perf lock)
• §6.16Linux Kernel Memory Model (LKMM, litmus tests)

Part VII — Network Stack Internals

LKN all · ULNI all · TCPIP Vol.1&2

• §7.1Socket Layer (struct socket → sock → tcp_sock)
• §7.2sk_buff — Core Data Structure (GSO, GRO, zero-copy)
• §7.3Network Device Layer (net_device, NAPI, TX/RX path)
• §7.4Traffic Control & QoS (Qdisc, HTB, cls_flower)
• §7.5IP Layer (ip_rcv, fragmentation, ICMP)
• §7.6Routing Subsystem (fib_table, LPM, fib_trie, policy routing)
• §7.7Neighbor Subsystem (ARP, NDP, proxy ARP, GARP)
• §7.8TCP/IP Deep Dive (state machine, CUBIC, BBR, SYN Cookie)
• §7.9UDP & Multicast socket
• §7.10Netfilter & NAT (5 hooks, conntrack, DNAT/SNAT)
• §7.11Network Bridge (FDB, MAC learning, STP)
• §7.12GRE & VXLAN Tunnels
• §7.13IPv6 (NDP, RA/RS, DHCPv6, extension headers)
• §7.14Multicast (IGMP, MLD, PIM-SM, RPF)
• §7.15DHCP Protocol & Proxy DHCP (DORA, DHCPv6)
• §7.16Routing Protocols (RIP, OSPF, BGP, BIRD)

Part VIII — Network Drivers & Hardware Interface

LDD Ch.17 · ULNI Ch.8,9 · DPDK docs

• §8.1PCI / PCIe Device Driver (BARs, MSI-X, pci_probe)
• §8.2Network Driver Model (TX/RX descriptor rings, DMA, TSO)
• §8.3SR-IOV (PF / VF, per-VF flow classification)
• §8.4DDIO (Intel Data Direct I/O)
• §8.5Character Devices (cdev, file_operations, UIO)
• §8.6Block Devices (gendisk, blk-mq, struct bio)

Part IX — DPDK (Userspace Networking) — Deep Dive

DPDKPG all · critical interview section

• §9.1Why DPDK: Kernel Bypass Architecture (UIO vs VFIO)
• §9.2DPDK Startup Flow (rte_eal_init 10 steps)
• §9.3PMD Poll Mode Driver (descriptor rings, DD bit, doorbell)
• §9.4NIC Multi-Queue, RSS & Flow Classification (rte_flow)
• §9.5Memory: Huge Pages, Mempool & Mbuf
• §9.6NUMA-Aware Programming
• §9.7Lock-Free Ring Buffer (rte_ring — CAS algorithm)
• §9.8Cache Optimization (alignment, prefetch, DDIO, WC)
• §9.9ACL & LPM Classification (DIR-24-8, rte_hash cuckoo)
• §9.10SR-IOV in DPDK (VF pass-through, VFIO)
• §9.11Hardware Offload (checksum, TSO, LRO, VXLAN offload)
• §9.12SIMD in DPDK (SSE4.2, AVX2, AVX-512)
• §9.13Virtio, vhost-user & vDPA
• §9.14Pipeline & Run-to-Completion Models
• §9.15DPDK Hot Upgrade (multi-process, shared memory)
• §9.16Session Management (fast path / slow path)
• §9.17QoS in DPDK (rte_meter, rte_sched, distributed rate limit)
• §9.18DPDK Bonding & Link Aggregation
• §9.19OVS-DPDK (EMC, dpcls, megaflow, VXLAN)

Part X — XDP (eXpress Data Path)

kernel docs · eBPF/XDP reference

• §10.1XDP Architecture & Motivation (XDP vs DPDK comparison)
• §10.2XDP Modes (native, generic, offloaded)
• §10.3AF_XDP Socket (UMEM, fill/completion/RX/TX rings)
• §10.4XDP Maps & Data Structures (BPF map types)
• §10.5XDP Use Cases (DDoS, Katran LB, Cilium, monitoring)

Part XI — Storage & File Systems

LKD Ch.13,14 · EXT4 docs

• §11.1VFS (super_block, inode, dentry, address_space)
• §11.2ext4 File System (extents, JBD2, delayed alloc)
• §11.3Block Layer (struct bio, blk-mq, I/O schedulers, O_DIRECT)
• §11.4B+ Tree (split/merge, lock coupling)
• §11.5Page Cache Management (LRU/MRU, double-write buffer)
• §11.6Disk Free Space Management (bitmap, buddy)
• §11.7Coroutines & Cooperative Scheduling (async I/O + ucontext)

Part XII — Virtualization & Containers

LKD Ch.18 · KVM docs · LXC/Docker

• §12.1CPU Virtualization (KVM/VMX, VMCS, VMEXIT)
• §12.2Memory Virtualization (EPT, balloon, KSM)
• §12.3VM Live Migration (dirty page tracking, pre-copy)
• §12.4Containers: Namespace & Cgroup v2
• §12.5Container Networking — CNI (veth, VXLAN, Cilium)
• §12.6Storage Virtualization (virtio-blk, vhost-user-blk, NVMe PT)

Part XIII — Hardware Communication & PCIe

PCIe spec · DPDK docs · LDD Ch.15

• §13.1PCIe Architecture (TLP, credits, LTSSM, lanes)
• §13.2Memory-Mapped BAR Access (MMIO, write-combining)
• §13.3DMA & IOMMU (bus address, VT-d, VFIO)
• §13.4NUMA & CPU Topology (libnuma, lscpu)

Part XIV — Debugging & Profiling Tools

LKD Ch.18 · perf docs · kernel tracing

• §14.1Network Debugging (tcpdump, ss, iperf3, ethtool)
• §14.2System Call Tracing (strace, ltrace, perf trace)
• §14.3Performance Profiling (perf stat/record/top, flamegraph)
• §14.4Kernel Debugging (gdb+KGDB, crash, KASAN, OOPS)
• §14.5Kernel Tracing (ftrace, kprobe, eBPF/bcc, bpftrace)
• §14.6Memory Debugging (valgrind, kmemleak, /proc/slabinfo)

Part XV — Distributed Systems (Raft)

Ongaro & Ousterhout

• §15.1Raft Consensus (leader election, log replication, safety)
• §15.2Raft Practical Concerns (snapshot, membership change, log replay)
• §15.3Performance Optimizations (pipelining, batching, 100K IOPS)

Part XVI — Load Balancing & Consistent Hashing

Resume projects · DPDK LPM/ACL

• §16.1Load Balancing Algorithms (RR, ECMP, consistent hashing)
• §16.2NAT Gateway Internals (SNAT port selection, HA)
• §16.3Session Synchronization (state machine replication, delta sync)

Appendix — Key Kernel Data Structures