mirror of
https://github.com/subhobhai943/SUB-OS.git
synced 2026-10-25 16:52:29 +00:00
subhobhai943andClaude Opus 5
f9400f6ac4
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
64 lines
2.2 KiB
C
64 lines
2.2 KiB
C
#ifndef _MM_PAGE_CACHE_H
|
|
#define _MM_PAGE_CACHE_H
|
|
|
|
#include <stdint.h>
|
|
#include <stddef.h>
|
|
#include <stdbool.h>
|
|
|
|
// Write-back page cache sitting between the VFS and the block layer.
|
|
//
|
|
// Every entry caches PAGE_CACHE_BLOCK_SIZE bytes of one block device, keyed by
|
|
// (device, page index). Lookups go through a hash table; eviction follows a
|
|
// CLOCK approximation of LRU, and dirty pages are written back before reuse.
|
|
|
|
#define PAGE_CACHE_BLOCK_SIZE 4096
|
|
#define PAGE_CACHE_SECTORS (PAGE_CACHE_BLOCK_SIZE / 512)
|
|
#define PAGE_CACHE_MAX_PAGES 64
|
|
|
|
typedef struct page_cache_entry {
|
|
char dev_name[32];
|
|
uint64_t page_index; // Offset in PAGE_CACHE_BLOCK_SIZE units
|
|
uint8_t* data;
|
|
bool valid;
|
|
bool dirty;
|
|
bool referenced; // CLOCK second-chance bit
|
|
uint32_t pin_count;
|
|
uint64_t last_access;
|
|
uint64_t hits;
|
|
} page_cache_entry_t;
|
|
|
|
typedef struct {
|
|
uint64_t hits;
|
|
uint64_t misses;
|
|
uint64_t evictions;
|
|
uint64_t writebacks;
|
|
uint64_t read_ios;
|
|
uint64_t write_ios;
|
|
uint32_t resident_pages;
|
|
uint32_t dirty_pages;
|
|
size_t memory_bytes;
|
|
} page_cache_stats_t;
|
|
|
|
void page_cache_init(void);
|
|
|
|
// Read/write through the cache. Offsets and lengths are arbitrary; the cache
|
|
// splits them across pages internally. Both return bytes transferred.
|
|
size_t page_cache_read(const char* dev_name, uint64_t offset, void* buf, size_t len);
|
|
size_t page_cache_write(const char* dev_name, uint64_t offset, const void* buf, size_t len);
|
|
|
|
// Borrow a page directly (pinned until page_cache_release).
|
|
page_cache_entry_t* page_cache_get(const char* dev_name, uint64_t page_index);
|
|
void page_cache_release(page_cache_entry_t* entry);
|
|
void page_cache_mark_dirty(page_cache_entry_t* entry);
|
|
|
|
int page_cache_sync(void); // Flush every dirty page
|
|
int page_cache_sync_dev(const char* dev_name); // Flush one device
|
|
int page_cache_invalidate(const char* dev_name); // Drop clean pages
|
|
void page_cache_drop_all(void);
|
|
|
|
page_cache_stats_t page_cache_get_stats(void);
|
|
uint32_t page_cache_hit_percent(void);
|
|
void page_cache_dump(void);
|
|
|
|
#endif // _MM_PAGE_CACHE_H
|