page_cache_sync_readahead — generic file readahead
void page_cache_sync_readahead ( | struct address_space * mapping, |
| struct file_ra_state * ra, | |
| struct file * filp, | |
| pgoff_t offset, | |
unsigned long req_size); |
mappingaddress_space which holds the pagecache and I/O vectors
rafile_ra_state which holds the readahead state
filp
passed on to ->readpage and ->readpages
offset
start offset into mapping, in pagecache page-sized units
req_sizehint: total size of the read which the caller is performing in pagecache pages
page_cache_sync_readahead should be called when a cache miss happened:
it will submit the read. The readahead logic may decide to piggyback more
pages onto the read request if access patterns suggest it will improve
performance.