Files
subhobhai943andClaude Opus 5 f9400f6ac4 feat(kernel): Add RB-tree/kfifo/hashtable, wait queues, futex, tiny RCU, page cache and KTest harness
Expands the kernel-and-TTY core with the primitives the higher layers have
been missing, plus an in-kernel harness that proves they work.

Data structures (lib/):
  - rbtree.c: Linux-compatible red-black tree with parent pointers, full
    insert/erase rebalancing, in-order iteration and an invariant validator.
  - kfifo.c: power-of-two byte ring with free-running indices, so the wrap
    path costs one mask instead of a branch per byte.
  - hashtable.c: separately-chained table with FNV-1a hashing, string or
    u64 keys, and rehash-on-growth at a 3/4 load factor.

Kernel subsystems:
  - kernel/wait.c: wait queues and one-shot completion barriers, backed by a
    static sleeper pool so a blocking path never re-enters the allocator.
  - kernel/futex.c: 32-bucket futex hash with value re-check, requeue, and an
    fmutex_t sleeping mutex built on the uncontended-fastpath protocol.
  - kernel/rcu.c: tiny RCU with reader nesting, deferred callbacks, kfree_rcu
    and rcu_assign_pointer/rcu_dereference publish barriers.
  - mm/page_cache.c: write-back block page cache, 4 KB pages indexed by
    (device, page), CLOCK second-chance eviction and dirty write-back.
  - kernel/ktest.c: KUnit-style harness with 6 built-in suites, 21 cases and
    735 assertions covering every subsystem above (all passing under QEMU).

LazyBox userland:
  - coreutils.c: sort, uniq, cut, tr, rev, tac, nl, seq, diff, xxd, du,
    factor, sum and truncate, reading through the VFS and handling the
    zero-length synthetic nodes that procfs and sysfs expose.
  - ktest, rcuinfo, futexinfo, waitinfo and pagecache diagnostics applets.

Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01L5yKJT4Wo2cV3rfPrwY5MP
2026-08-24 23:38:59 +05:30

51 lines
1.6 KiB
C

#ifndef _LIB_HASHTABLE_H
#define _LIB_HASHTABLE_H
#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
// Separately-chained hash table with FNV-1a hashing and automatic growth.
// Keys are either NUL-terminated strings (owned copies) or raw 64-bit ids.
typedef struct hnode {
uint64_t hash;
char* skey; // NULL for integer-keyed entries
uint64_t ikey;
void* value;
struct hnode* next;
} hnode_t;
typedef struct hashtable {
hnode_t** buckets;
size_t bucket_count;
size_t entries;
size_t collisions;
bool string_keys;
} hashtable_t;
uint64_t hash_fnv1a(const void* data, size_t len);
uint64_t hash_string(const char* s);
uint64_t hash_u64(uint64_t v);
hashtable_t* hashtable_create(size_t initial_buckets, bool string_keys);
void hashtable_destroy(hashtable_t* ht);
int hashtable_put(hashtable_t* ht, const char* key, void* value);
void* hashtable_get(const hashtable_t* ht, const char* key);
bool hashtable_remove(hashtable_t* ht, const char* key);
int hashtable_put_u64(hashtable_t* ht, uint64_t key, void* value);
void* hashtable_get_u64(const hashtable_t* ht, uint64_t key);
bool hashtable_remove_u64(hashtable_t* ht, uint64_t key);
size_t hashtable_size(const hashtable_t* ht);
size_t hashtable_buckets(const hashtable_t* ht);
size_t hashtable_collisions(const hashtable_t* ht);
size_t hashtable_longest_chain(const hashtable_t* ht);
typedef void (*hashtable_iter_fn)(const hnode_t* node, void* ctx);
void hashtable_foreach(const hashtable_t* ht, hashtable_iter_fn fn, void* ctx);
#endif // _LIB_HASHTABLE_H