Module page_cache 

Global Page Cache Manager

Provides a unified page cache for all filesystem operations (read/write/mmap). This cache is shared across all file objects pointing to the same file, ensuring consistency and memory efficiency.

Phase 0 Implementation

Current implementation includes:

• Page allocation and caching with CacheId-based indexing
• Pin-based protection against eviction during active use
• Dirty page tracking for write operations
• Object-level locking for mmap support
• Flush operations for writeback

Not yet implemented:

• Page eviction (LRU or similar policy)
• LOADING state coordination for concurrent access
• Integration with filesystem read/write operations (Phase 1)
• Demand paging for mmap (Phase 2)

Usage

use crate::mem::page_cache::PageCacheManager;

let paddr = PageCacheManager::global().get_or_create_pinned(cache_id, page_index, |paddr| {
    // Load page content from disk to paddr
    Ok(())
})?;
// Use the page...
PageCacheManager::global().unpin(cache_id, page_index);

Structs

PageCacheEntry

Entry in the page cache representing a single cached page

PageCacheManager

Global page cache manager

PinnedPage

RAII guard for a pinned page.

Statics

GLOBAL_PAGE_CACHE

Global page cache instance

Type Aliases

PageIndex

Page index within a file (0, 1, 2, …)

PhysicalAddress

Physical address of a page