Function prefetch_pages

nodedb/src/data/io/prefetch.rs:36–48

Pre-fetch a range of pages into the page cache. Uses `madvise(MADV_WILLNEED)` which is non-blocking — the kernel initiates readahead I/O and returns immediately. The TPC core continues processing other work while pages load asynchronously. # Safety `ptr` must point to a valid mmap'd region of at least `len` bytes.

(ptr: *const u8, len: usize)

///
/// `ptr` must point to a valid mmap'd region of at least `len` bytes.
pub fn prefetch_pages(ptr: *const u8, len: usize) {
    if ptr.is_null() || len == 0 {
        return;
    }
    // Align to page boundary.
    let page_size = 4096;
    let aligned_ptr = (ptr as usize & !(page_size - 1)) as *mut libc::c_void;
    let aligned_len = (len + page_size - 1) & !(page_size - 1);

    unsafe {
        libc::madvise(aligned_ptr, aligned_len, libc::MADV_WILLNEED);
    }
}

/// Pre-fetch a batch of disjoint memory ranges.
///