block: separate priority boosting from REQ_META
Add a new REQ_PRIO to let requests preempt others in the cfq I/O schedule,
and lave REQ_META purely for marking requests as metadata in blktrace.
All existing callers of REQ_META except for XFS are updated to also
set REQ_PRIO for now.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Namhyung Kim <namhyung@gmail.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index 747238c..be29858 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -37,7 +37,7 @@
{
struct buffer_head *bh, *head;
int nr_underway = 0;
- int write_op = REQ_META |
+ int write_op = REQ_META | REQ_PRIO |
(wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
BUG_ON(!PageLocked(page));
@@ -225,7 +225,7 @@
}
bh->b_end_io = end_buffer_read_sync;
get_bh(bh);
- submit_bh(READ_SYNC | REQ_META, bh);
+ submit_bh(READ_SYNC | REQ_META | REQ_PRIO, bh);
if (!(flags & DIO_WAIT))
return 0;
@@ -435,7 +435,7 @@
if (buffer_uptodate(first_bh))
goto out;
if (!buffer_locked(first_bh))
- ll_rw_block(READ_SYNC | REQ_META, 1, &first_bh);
+ ll_rw_block(READ_SYNC | REQ_META | REQ_PRIO, 1, &first_bh);
dblock++;
extlen--;