page_cache_async_readahead (9)

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);

mapping

address_space which holds the pagecache and I/O vectors

ra

file_ra_state which holds the readahead state

filp

passed on to ->readpage and ->readpages

page

the page at offset which has the PG_readahead flag set

offset

start offset into mapping, in pagecache page-sized units

req_size

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.