- void page_cache_async_readahead(struct address_space * mapping, struct file_ra_state * ra, struct file * filp, struct page * page, pgoff_t offset, unsigned long req_size);
- address_space which holds the pagecache and I/O vectors
- file_ra_state which holds the readahead state
- passed on to ->readpage and ->readpages
- the page at offset which has the PG_readahead flag set
- start offset into mapping, in pagecache page-sized units
- hint: total size of the read which the caller is performing in pagecache pages
page_cache_async_readahead should be called when a page is used which has the PG_readahead flag; this is a marker to suggest that the application has used up enough of the readahead window that we should start pulling in more pages.