Trait AllocPage

pub trait AllocPage: LoadPage {
    // Required methods
    unsafe fn alloc_page(&mut self) -> Result<MutPage, Self::Error>;
    unsafe fn alloc_contiguous(
        &mut self,
        length: u64,
    ) -> Result<MutPage, Self::Error>;
    fn incr_rc(&mut self, off: u64) -> Result<usize, Self::Error>;
    unsafe fn decr_rc(&mut self, off: u64) -> Result<usize, Self::Error>;
    unsafe fn decr_rc_owned(&mut self, off: u64) -> Result<usize, Self::Error>;

    // Provided method
    unsafe fn alloc_page_no_dirty(&mut self) -> Result<MutPage, Self::Error> { ... }
}

Trait for allocating and freeing pages.

Required Methods

unsafe fn alloc_page(&mut self) -> Result<MutPage, Self::Error>

Allocate a new page.

unsafe fn alloc_contiguous( &mut self, length: u64, ) -> Result<MutPage, Self::Error>

Allocate many contiguous pages, return the first one. The dirty bit is not needed.

fn incr_rc(&mut self, off: u64) -> Result<usize, Self::Error>

Increment the page’s reference count.

unsafe fn decr_rc(&mut self, off: u64) -> Result<usize, Self::Error>

Decrement the page’s reference count, assuming the page was first allocated by another transaction. If the RC reaches 0, free the page. Must return the new RC (0 if freed).

unsafe fn decr_rc_owned(&mut self, off: u64) -> Result<usize, Self::Error>

Same as Self::decr_rc, but for pages allocated by the current transaction. This is an important distinction, as pages allocated by the current transaction can be reused immediately after being freed.

Provided Methods

unsafe fn alloc_page_no_dirty(&mut self) -> Result<MutPage, Self::Error>

Allocate a new page, in a context where we cannot use the “dirty bit” trick directly on the page.

Implementors

impl<E: Borrow<Env>, T> AllocPage for MutTxn<E, T>