Linux Kernel 2.6.24 Read File

sys_read

image.png

do_sync_read

image.png

generic_file_aio_read

image.png

do_generic_mapping_read

image.png

readahead后也没有找到page

image.png

struct file_ra_state {
    pgoff_t start;          /* where readahead started */
    unsigned int size;      /* # of readahead pages */
    unsigned int async_size;    /* do asynchronous readahead when
                       there are only # of pages ahead */

    unsigned int ra_pages;      /* Maximum readahead window */
    int mmap_miss;          /* Cache miss stat for mmap accesses */
    loff_t prev_pos;        /* Cache last read() position */
};