[PATCH 2/2 v2] block: separate priority boosting from REQ_META
From: Christoph Hellwig
Date: Tue Aug 23 2011 - 06:09:51 EST
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@xxxxxx>
Index: linux-2.6/block/cfq-iosched.c
===================================================================
--- linux-2.6.orig/block/cfq-iosched.c 2011-08-23 02:29:10.843355420 +0200
+++ linux-2.6/block/cfq-iosched.c 2011-08-23 10:18:19.430245519 +0200
@@ -130,8 +130,8 @@ struct cfq_queue {
unsigned long slice_end;
long slice_resid;
- /* pending metadata requests */
- int meta_pending;
+ /* pending priority requests */
+ int prio_pending;
/* number of requests that are on the dispatch list or inside driver */
int dispatched;
@@ -684,8 +684,8 @@ cfq_choose_req(struct cfq_data *cfqd, st
if (rq_is_sync(rq1) != rq_is_sync(rq2))
return rq_is_sync(rq1) ? rq1 : rq2;
- if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_META)
- return rq1->cmd_flags & REQ_META ? rq1 : rq2;
+ if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_PRIO)
+ return rq1->cmd_flags & REQ_PRIO ? rq1 : rq2;
s1 = blk_rq_pos(rq1);
s2 = blk_rq_pos(rq2);
@@ -1612,9 +1612,9 @@ static void cfq_remove_request(struct re
cfqq->cfqd->rq_queued--;
cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg,
rq_data_dir(rq), rq_is_sync(rq));
- if (rq->cmd_flags & REQ_META) {
- WARN_ON(!cfqq->meta_pending);
- cfqq->meta_pending--;
+ if (rq->cmd_flags & REQ_PRIO) {
+ WARN_ON(!cfqq->prio_pending);
+ cfqq->prio_pending--;
}
}
@@ -3372,7 +3372,7 @@ cfq_should_preempt(struct cfq_data *cfqd
* So both queues are sync. Let the new request get disk time if
* it's a metadata request and the current queue is doing regular IO.
*/
- if ((rq->cmd_flags & REQ_META) && !cfqq->meta_pending)
+ if ((rq->cmd_flags & REQ_PRIO) && !cfqq->prio_pending)
return true;
/*
@@ -3439,8 +3439,8 @@ cfq_rq_enqueued(struct cfq_data *cfqd, s
struct cfq_io_context *cic = RQ_CIC(rq);
cfqd->rq_queued++;
- if (rq->cmd_flags & REQ_META)
- cfqq->meta_pending++;
+ if (rq->cmd_flags & REQ_PRIO)
+ cfqq->prio_pending++;
cfq_update_io_thinktime(cfqd, cfqq, cic);
cfq_update_io_seektime(cfqd, cfqq, rq);
Index: linux-2.6/drivers/mmc/card/block.c
===================================================================
--- linux-2.6.orig/drivers/mmc/card/block.c 2011-08-23 02:29:10.830022159 +0200
+++ linux-2.6/drivers/mmc/card/block.c 2011-08-23 10:18:19.430245519 +0200
@@ -926,6 +926,9 @@ static void mmc_blk_rw_rq_prep(struct mm
/*
* Reliable writes are used to implement Forced Unit Access and
* REQ_META accesses, and are supported only on MMCs.
+ *
+ * XXX: this really needs a good explanation of why REQ_META
+ * is treated special.
*/
bool do_rel_wr = ((req->cmd_flags & REQ_FUA) ||
(req->cmd_flags & REQ_META)) &&
Index: linux-2.6/fs/ext3/inode.c
===================================================================
--- linux-2.6.orig/fs/ext3/inode.c 2011-08-23 10:18:18.910248335 +0200
+++ linux-2.6/fs/ext3/inode.c 2011-08-23 10:18:19.433578834 +0200
@@ -1134,7 +1134,7 @@ struct buffer_head *ext3_bread(handle_t
return bh;
if (buffer_uptodate(bh))
return bh;
- ll_rw_block(READ | REQ_META, 1, &bh);
+ ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
wait_on_buffer(bh);
if (buffer_uptodate(bh))
return bh;
@@ -2807,7 +2807,7 @@ make_io:
trace_ext3_load_inode(inode);
get_bh(bh);
bh->b_end_io = end_buffer_read_sync;
- submit_bh(READ | REQ_META, bh);
+ submit_bh(READ | REQ_META | REQ_PRIO, bh);
wait_on_buffer(bh);
if (!buffer_uptodate(bh)) {
ext3_error(inode->i_sb, "ext3_get_inode_loc",
Index: linux-2.6/fs/ext3/namei.c
===================================================================
--- linux-2.6.orig/fs/ext3/namei.c 2011-08-23 10:18:18.910248335 +0200
+++ linux-2.6/fs/ext3/namei.c 2011-08-23 10:18:19.436912149 +0200
@@ -922,7 +922,8 @@ restart:
bh = ext3_getblk(NULL, dir, b++, 0, &err);
bh_use[ra_max] = bh;
if (bh)
- ll_rw_block(READ | REQ_META, 1, &bh);
+ ll_rw_block(READ | REQ_META | REQ_PRIO,
+ 1, &bh);
}
}
if ((bh = bh_use[ra_ptr++]) == NULL)
Index: linux-2.6/fs/ext4/inode.c
===================================================================
--- linux-2.6.orig/fs/ext4/inode.c 2011-08-23 10:18:18.910248335 +0200
+++ linux-2.6/fs/ext4/inode.c 2011-08-23 10:18:19.440245464 +0200
@@ -650,7 +650,7 @@ struct buffer_head *ext4_bread(handle_t
return bh;
if (buffer_uptodate(bh))
return bh;
- ll_rw_block(READ | REQ_META, 1, &bh);
+ ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
wait_on_buffer(bh);
if (buffer_uptodate(bh))
return bh;
@@ -3301,7 +3301,7 @@ make_io:
trace_ext4_load_inode(inode);
get_bh(bh);
bh->b_end_io = end_buffer_read_sync;
- submit_bh(READ | REQ_META, bh);
+ submit_bh(READ | REQ_META | REQ_PRIO, bh);
wait_on_buffer(bh);
if (!buffer_uptodate(bh)) {
EXT4_ERROR_INODE_BLOCK(inode, block,
Index: linux-2.6/fs/ext4/namei.c
===================================================================
--- linux-2.6.orig/fs/ext4/namei.c 2011-08-23 10:18:18.913581650 +0200
+++ linux-2.6/fs/ext4/namei.c 2011-08-23 10:18:19.443578779 +0200
@@ -922,7 +922,8 @@ restart:
bh = ext4_getblk(NULL, dir, b++, 0, &err);
bh_use[ra_max] = bh;
if (bh)
- ll_rw_block(READ | REQ_META, 1, &bh);
+ ll_rw_block(READ | REQ_META | REQ_PRIO,
+ 1, &bh);
}
}
if ((bh = bh_use[ra_ptr++]) == NULL)
Index: linux-2.6/fs/gfs2/log.c
===================================================================
--- linux-2.6.orig/fs/gfs2/log.c 2011-08-23 02:29:10.883355202 +0200
+++ linux-2.6/fs/gfs2/log.c 2011-08-23 10:18:19.446912094 +0200
@@ -624,9 +624,9 @@ static void log_write_header(struct gfs2
bh->b_end_io = end_buffer_write_sync;
get_bh(bh);
if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags))
- submit_bh(WRITE_SYNC | REQ_META, bh);
+ submit_bh(WRITE_SYNC | REQ_META | REQ_PRIO, bh);
else
- submit_bh(WRITE_FLUSH_FUA | REQ_META, bh);
+ submit_bh(WRITE_FLUSH_FUA | REQ_META | REQ_PRIO, bh);
wait_on_buffer(bh);
if (!buffer_uptodate(bh))
Index: linux-2.6/fs/gfs2/meta_io.c
===================================================================
--- linux-2.6.orig/fs/gfs2/meta_io.c 2011-08-23 02:29:10.890021834 +0200
+++ linux-2.6/fs/gfs2/meta_io.c 2011-08-23 10:18:19.446912094 +0200
@@ -37,7 +37,7 @@ static int gfs2_aspace_writepage(struct
{
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 @@ int gfs2_meta_read(struct gfs2_glock *gl
}
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 @@ struct buffer_head *gfs2_meta_ra(struct
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--;
Index: linux-2.6/fs/gfs2/ops_fstype.c
===================================================================
--- linux-2.6.orig/fs/gfs2/ops_fstype.c 2011-08-23 02:29:10.896688465 +0200
+++ linux-2.6/fs/gfs2/ops_fstype.c 2011-08-23 10:18:19.450245409 +0200
@@ -224,7 +224,7 @@ static int gfs2_read_super(struct gfs2_s
bio->bi_end_io = end_bio_io_page;
bio->bi_private = page;
- submit_bio(READ_SYNC | REQ_META, bio);
+ submit_bio(READ_SYNC | REQ_META | REQ_PRIO, bio);
wait_on_page_locked(page);
bio_put(bio);
if (!PageUptodate(page)) {
Index: linux-2.6/fs/gfs2/quota.c
===================================================================
--- linux-2.6.orig/fs/gfs2/quota.c 2011-08-23 10:18:18.916914965 +0200
+++ linux-2.6/fs/gfs2/quota.c 2011-08-23 10:18:19.450245409 +0200
@@ -709,7 +709,7 @@ get_a_page:
set_buffer_uptodate(bh);
if (!buffer_uptodate(bh)) {
- ll_rw_block(READ | REQ_META, 1, &bh);
+ ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh);
wait_on_buffer(bh);
if (!buffer_uptodate(bh))
goto unlock_out;
Index: linux-2.6/include/linux/blk_types.h
===================================================================
--- linux-2.6.orig/include/linux/blk_types.h 2011-08-23 02:29:10.903355095 +0200
+++ linux-2.6/include/linux/blk_types.h 2011-08-23 10:18:45.196772595 +0200
@@ -124,6 +124,7 @@ enum rq_flag_bits {
__REQ_SYNC, /* request is sync (sync write or read) */
__REQ_META, /* metadata io request */
+ __REQ_PRIO, /* boost priority in cfq */
__REQ_DISCARD, /* request to discard sectors */
__REQ_SECURE, /* secure discard (used with __REQ_DISCARD) */
@@ -161,14 +162,15 @@ enum rq_flag_bits {
#define REQ_FAILFAST_DRIVER (1 << __REQ_FAILFAST_DRIVER)
#define REQ_SYNC (1 << __REQ_SYNC)
#define REQ_META (1 << __REQ_META)
+#define REQ_PRIO (1 << __REQ_PRIO)
#define REQ_DISCARD (1 << __REQ_DISCARD)
#define REQ_NOIDLE (1 << __REQ_NOIDLE)
#define REQ_FAILFAST_MASK \
(REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER)
#define REQ_COMMON_MASK \
- (REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_DISCARD | \
- REQ_NOIDLE | REQ_FLUSH | REQ_FUA | REQ_SECURE)
+ (REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | \
+ REQ_DISCARD | REQ_NOIDLE | REQ_FLUSH | REQ_FUA | REQ_SECURE)
#define REQ_CLONE_MASK REQ_COMMON_MASK
#define REQ_RAHEAD (1 << __REQ_RAHEAD)
--
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