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| author | Fengguang Wu <wfg@mail.ustc.edu.cn> | 2007-07-19 04:47:57 -0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-19 13:04:43 -0400 |
| commit | 46fc3e7b4e7233a0ac981ac9084b55217318d04d (patch) | |
| tree | 555bededb43671605fa085d3b4d330d31aa4af5c /mm/fadvise.c | |
| parent | d77c2d7cc5126639a47d73300b40d461f2811a0f (diff) | |
readahead: add look-ahead support to __do_page_cache_readahead()
Add look-ahead support to __do_page_cache_readahead().
It works by
- mark the Nth backwards page with PG_readahead,
(which instructs the page's first reader to invoke readahead)
- and only do the marking for newly allocated pages.
(to prevent blindly doing readahead on already cached pages)
Look-ahead is a technique to achieve I/O pipelining:
While the application is working through a chunk of cached pages, the kernel
reads-ahead the next chunk of pages _before_ time of need. It effectively
hides low level I/O latencies to high level applications.
Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
Cc: Steven Pratt <slpratt@austin.ibm.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/fadvise.c')
0 files changed, 0 insertions, 0 deletions