On Sat, Jan 22, 2011 at 01:17:26AM +0000, Jens Axboe wrote:
> Signed-off-by: Jens Axboe <[email protected]>
> ---
> mm/filemap.c | 7 +++++++
> 1 files changed, 7 insertions(+), 0 deletions(-)
>
> diff --git a/mm/filemap.c b/mm/filemap.c
> index 380776c..f9a29c8 100644
> --- a/mm/filemap.c
> +++ b/mm/filemap.c
> @@ -1243,12 +1243,15 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
> unsigned long seg = 0;
> size_t count;
> loff_t *ppos = &iocb->ki_pos;
> + struct blk_plug plug;
>
> count = 0;
> retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
> if (retval)
> return retval;
>
> + blk_start_plug(&plug);
> +
Jens,
IIUC, read requests will be considered SYNC and it looks like that
__make_request() will dispatch all the SYNC requests immediately. If
that's the case then for read path blk_plug mechanism is not required?
Thanks
Vivek
On 2011-03-04 05:09, Vivek Goyal wrote:
> On Sat, Jan 22, 2011 at 01:17:26AM +0000, Jens Axboe wrote:
>> Signed-off-by: Jens Axboe <[email protected]>
>> ---
>> mm/filemap.c | 7 +++++++
>> 1 files changed, 7 insertions(+), 0 deletions(-)
>>
>> diff --git a/mm/filemap.c b/mm/filemap.c
>> index 380776c..f9a29c8 100644
>> --- a/mm/filemap.c
>> +++ b/mm/filemap.c
>> @@ -1243,12 +1243,15 @@ generic_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
>> unsigned long seg = 0;
>> size_t count;
>> loff_t *ppos = &iocb->ki_pos;
>> + struct blk_plug plug;
>>
>> count = 0;
>> retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
>> if (retval)
>> return retval;
>>
>> + blk_start_plug(&plug);
>> +
>
> Jens,
>
> IIUC, read requests will be considered SYNC and it looks like that
> __make_request() will dispatch all the SYNC requests immediately. If
> that's the case then for read path blk_plug mechanism is not required?
Good catch, we need to modify that logic. If the task is currently
plugged, it should not dispatch until blk_finish_plug() is called.
Essentially SYNC will not control dispatch. Will allow us to clean up
that logic, too.
--
Jens Axboe
On Fri, Mar 04, 2011 at 02:22:21PM +0100, Jens Axboe wrote:
> Good catch, we need to modify that logic. If the task is currently
> plugged, it should not dispatch until blk_finish_plug() is called.
> Essentially SYNC will not control dispatch. Will allow us to clean up
> that logic, too.
<broken-record-mode>
Time to use the opportunity to sort out what the various bio/request
flags mean.
REQ_UNPLUG should simply go away with the explicit stack plugging.
What's left for REQ_SYNC? It'll control if the request goes into the
sync bucket and some cfq tweaks. We should clearly document what it
does.
REQ_META? Maybe we should finally agree what it does and decide if it
should be used consistenly. Especially the priority over REQ_SYNC in
cfq still looks somewhat odd, as does the totally inconsequent use.
</broken-record-mode>
On 2011-03-04 14:25, [email protected] wrote:
> On Fri, Mar 04, 2011 at 02:22:21PM +0100, Jens Axboe wrote:
>> Good catch, we need to modify that logic. If the task is currently
>> plugged, it should not dispatch until blk_finish_plug() is called.
>> Essentially SYNC will not control dispatch. Will allow us to clean up
>> that logic, too.
>
> <broken-record-mode>
>
> Time to use the opportunity to sort out what the various bio/request
> flags mean.
>
> REQ_UNPLUG should simply go away with the explicit stack plugging.
> What's left for REQ_SYNC? It'll control if the request goes into the
> sync bucket and some cfq tweaks. We should clearly document what it
> does.
Yes, REQ_UNPLUG goes away, it has no meaning anymore since the plugging
is explicitly done by the caller.
With REQ_SYNC, lets make the sync/async thing apply to both reads and
writes. Right now reads are inherently sync, writes are sometimes
(O_DIRECT). So lets stop making it more murky by mixing up READ and
SYNC.
> REQ_META? Maybe we should finally agree what it does and decide if it
> should be used consistenly. Especially the priority over REQ_SYNC in
> cfq still looks somewhat odd, as does the totally inconsequent use.
For me it was primarily a blktrace hint, but yes it does have prio boost
properties in CFQ as well. I'm inclined to let those stay the way they
are. Not sure we can properly call it anything outside of a hint that
these IO have slightly higher priority, at least I would not want to
lock the IO scheduler into to something more concrete than that.
--
Jens Axboe
On Fri, Mar 04, 2011 at 02:40:09PM +0100, Jens Axboe wrote:
> > REQ_META? Maybe we should finally agree what it does and decide if it
> > should be used consistenly. Especially the priority over REQ_SYNC in
> > cfq still looks somewhat odd, as does the totally inconsequent use.
>
> For me it was primarily a blktrace hint, but yes it does have prio boost
> properties in CFQ as well. I'm inclined to let those stay the way they
> are. Not sure we can properly call it anything outside of a hint that
> these IO have slightly higher priority, at least I would not want to
> lock the IO scheduler into to something more concrete than that.
The problem is that these two meanings are inherently conflicting.
Metadata updates do not have to be synchronous or have any kind of
priority. In fact for XFS they normall aren't, and I'd be surprised it
the same isn't true for other journalled filesystems.
Priority metadata goes into the log, which for XFS is always written as
a FLUSH+FUA bio. Writeback of metadata happens asynchronously in the
background, and only becomes a priority if the journal is full and we'll
need to make space available.
So giving plain REQ_META a priority boost makes it impossible to use it
for the blktrace annotation use case. One could only apply the boost
for the REQ_SYNC + REQ_META combination, but even that seems rather
hackish to me. I'd really love to see numbers where the additional
boost of REQ_META over REQ_SYNC makes any difference.
On 2011-03-04 15:08, [email protected] wrote:
> On Fri, Mar 04, 2011 at 02:40:09PM +0100, Jens Axboe wrote:
>>> REQ_META? Maybe we should finally agree what it does and decide if it
>>> should be used consistenly. Especially the priority over REQ_SYNC in
>>> cfq still looks somewhat odd, as does the totally inconsequent use.
>>
>> For me it was primarily a blktrace hint, but yes it does have prio boost
>> properties in CFQ as well. I'm inclined to let those stay the way they
>> are. Not sure we can properly call it anything outside of a hint that
>> these IO have slightly higher priority, at least I would not want to
>> lock the IO scheduler into to something more concrete than that.
>
> The problem is that these two meanings are inherently conflicting.
> Metadata updates do not have to be synchronous or have any kind of
> priority. In fact for XFS they normall aren't, and I'd be surprised it
> the same isn't true for other journalled filesystems.
>
> Priority metadata goes into the log, which for XFS is always written as
> a FLUSH+FUA bio. Writeback of metadata happens asynchronously in the
> background, and only becomes a priority if the journal is full and we'll
> need to make space available.
>
> So giving plain REQ_META a priority boost makes it impossible to use it
> for the blktrace annotation use case. One could only apply the boost
> for the REQ_SYNC + REQ_META combination, but even that seems rather
> hackish to me. I'd really love to see numbers where the additional
> boost of REQ_META over REQ_SYNC makes any difference.
Seems only gfs2 actually sets the flag now. So how about we remove the
prio boost for meta data and just retain it as an information attribute?
If there's a need for this slight boosts, it is probably best done
explicitly being signalled from the caller.
--
Jens Axboe
On Fri, Mar 04, 2011 at 11:07:51PM +0100, Jens Axboe wrote:
> Seems only gfs2 actually sets the flag now. So how about we remove the
> prio boost for meta data and just retain it as an information attribute?
ext3/4 also use it for inodes and directories. XFS has code to use, but
it's currently unreachable.
On 2011-03-04 14:25, [email protected] wrote:
> REQ_UNPLUG should simply go away with the explicit stack plugging.
> What's left for REQ_SYNC? It'll control if the request goes into the
> sync bucket and some cfq tweaks. We should clearly document what it
> does.
How about the below? It gets rid of REQ_UNPLUG.
diff --git a/block/blk-core.c b/block/blk-core.c
index 82a4589..7e9715a 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1290,7 +1290,7 @@ get_rq:
}
plug = current->plug;
- if (plug && !sync) {
+ if (plug) {
if (!plug->should_sort && !list_empty(&plug->list)) {
struct request *__rq;
diff --git a/drivers/block/drbd/drbd_actlog.c b/drivers/block/drbd/drbd_actlog.c
index 2096628..aca3024 100644
--- a/drivers/block/drbd/drbd_actlog.c
+++ b/drivers/block/drbd/drbd_actlog.c
@@ -80,7 +80,7 @@ static int _drbd_md_sync_page_io(struct drbd_conf *mdev,
if ((rw & WRITE) && !test_bit(MD_NO_FUA, &mdev->flags))
rw |= REQ_FUA;
- rw |= REQ_UNPLUG | REQ_SYNC;
+ rw |= REQ_SYNC;
bio = bio_alloc(GFP_NOIO, 1);
bio->bi_bdev = bdev->md_bdev;
diff --git a/drivers/block/drbd/drbd_int.h b/drivers/block/drbd/drbd_int.h
index 0b5718e..b0bd27d 100644
--- a/drivers/block/drbd/drbd_int.h
+++ b/drivers/block/drbd/drbd_int.h
@@ -377,7 +377,7 @@ union p_header {
#define DP_HARDBARRIER 1 /* depricated */
#define DP_RW_SYNC 2 /* equals REQ_SYNC */
#define DP_MAY_SET_IN_SYNC 4
-#define DP_UNPLUG 8 /* equals REQ_UNPLUG */
+#define DP_UNPLUG 8 /* not used anymore */
#define DP_FUA 16 /* equals REQ_FUA */
#define DP_FLUSH 32 /* equals REQ_FLUSH */
#define DP_DISCARD 64 /* equals REQ_DISCARD */
diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 6049cb8..8a43ce0 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2477,12 +2477,11 @@ static u32 bio_flags_to_wire(struct drbd_conf *mdev, unsigned long bi_rw)
{
if (mdev->agreed_pro_version >= 95)
return (bi_rw & REQ_SYNC ? DP_RW_SYNC : 0) |
- (bi_rw & REQ_UNPLUG ? DP_UNPLUG : 0) |
(bi_rw & REQ_FUA ? DP_FUA : 0) |
(bi_rw & REQ_FLUSH ? DP_FLUSH : 0) |
(bi_rw & REQ_DISCARD ? DP_DISCARD : 0);
else
- return bi_rw & (REQ_SYNC | REQ_UNPLUG) ? DP_RW_SYNC : 0;
+ return bi_rw & REQ_SYNC ? DP_RW_SYNC : 0;
}
/* Used to send write requests
diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c
index 84132f8..8e68be9 100644
--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -1100,8 +1100,6 @@ next_bio:
/* > e->sector, unless this is the first bio */
bio->bi_sector = sector;
bio->bi_bdev = mdev->ldev->backing_bdev;
- /* we special case some flags in the multi-bio case, see below
- * (REQ_UNPLUG) */
bio->bi_rw = rw;
bio->bi_private = e;
bio->bi_end_io = drbd_endio_sec;
@@ -1130,10 +1128,6 @@ next_bio:
bios = bios->bi_next;
bio->bi_next = NULL;
- /* strip off REQ_UNPLUG unless it is the last bio */
- if (bios)
- bio->bi_rw &= ~REQ_UNPLUG;
-
drbd_generic_make_request(mdev, fault_type, bio);
} while (bios);
return 0;
@@ -1621,12 +1615,11 @@ static unsigned long write_flags_to_bio(struct drbd_conf *mdev, u32 dpf)
{
if (mdev->agreed_pro_version >= 95)
return (dpf & DP_RW_SYNC ? REQ_SYNC : 0) |
- (dpf & DP_UNPLUG ? REQ_UNPLUG : 0) |
(dpf & DP_FUA ? REQ_FUA : 0) |
(dpf & DP_FLUSH ? REQ_FUA : 0) |
(dpf & DP_DISCARD ? REQ_DISCARD : 0);
else
- return dpf & DP_RW_SYNC ? (REQ_SYNC | REQ_UNPLUG) : 0;
+ return dpf & DP_RW_SYNC ? REQ_SYNC : 0;
}
/* mirrored write */
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 54bfc27..ca203cb 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -347,7 +347,7 @@ static void write_page(struct bitmap *bitmap, struct page *page, int wait)
atomic_inc(&bitmap->pending_writes);
set_buffer_locked(bh);
set_buffer_mapped(bh);
- submit_bh(WRITE | REQ_UNPLUG | REQ_SYNC, bh);
+ submit_bh(WRITE | REQ_SYNC, bh);
bh = bh->b_this_page;
}
diff --git a/drivers/md/dm-io.c b/drivers/md/dm-io.c
index 136d4f7..76a5af0 100644
--- a/drivers/md/dm-io.c
+++ b/drivers/md/dm-io.c
@@ -352,7 +352,7 @@ static void dispatch_io(int rw, unsigned int num_regions,
BUG_ON(num_regions > DM_IO_MAX_REGIONS);
if (sync)
- rw |= REQ_SYNC | REQ_UNPLUG;
+ rw |= REQ_SYNC;
/*
* For multiple regions we need to be careful to rewind
diff --git a/drivers/md/dm-kcopyd.c b/drivers/md/dm-kcopyd.c
index e8429ce..2c880e9 100644
--- a/drivers/md/dm-kcopyd.c
+++ b/drivers/md/dm-kcopyd.c
@@ -363,11 +363,8 @@ static int run_io_job(struct kcopyd_job *job)
if (job->rw == READ)
r = dm_io(&io_req, 1, &job->source, NULL);
- else {
- if (job->num_dests > 1)
- io_req.bi_rw |= REQ_UNPLUG;
+ else
r = dm_io(&io_req, job->num_dests, job->dests, NULL);
- }
return r;
}
diff --git a/drivers/md/md.c b/drivers/md/md.c
index ca0d79c..28f9c1e 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -777,8 +777,7 @@ void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
bio->bi_end_io = super_written;
atomic_inc(&mddev->pending_writes);
- submit_bio(REQ_WRITE | REQ_SYNC | REQ_UNPLUG | REQ_FLUSH | REQ_FUA,
- bio);
+ submit_bio(REQ_WRITE | REQ_SYNC | REQ_FLUSH | REQ_FUA, bio);
}
void md_super_wait(mddev_t *mddev)
@@ -806,7 +805,7 @@ int sync_page_io(mdk_rdev_t *rdev, sector_t sector, int size,
struct completion event;
int ret;
- rw |= REQ_SYNC | REQ_UNPLUG;
+ rw |= REQ_SYNC;
bio->bi_bdev = (metadata_op && rdev->meta_bdev) ?
rdev->meta_bdev : rdev->bdev;
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 92ac519..b76f7cd 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2182,7 +2182,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc,
unsigned long nr_written = 0;
if (wbc->sync_mode == WB_SYNC_ALL)
- write_flags = WRITE_SYNC_PLUG;
+ write_flags = WRITE_SYNC;
else
write_flags = WRITE;
diff --git a/fs/buffer.c b/fs/buffer.c
index f903f2e..19ae76a 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -767,7 +767,7 @@ static int fsync_buffers_list(spinlock_t *lock, struct list_head *list)
* still in flight on potentially older
* contents.
*/
- write_dirty_buffer(bh, WRITE_SYNC_PLUG);
+ write_dirty_buffer(bh, WRITE_SYNC);
/*
* Kick off IO for the previous mapping. Note
@@ -1602,14 +1602,11 @@ EXPORT_SYMBOL(unmap_underlying_metadata);
* prevents this contention from occurring.
*
* If block_write_full_page() is called with wbc->sync_mode ==
- * WB_SYNC_ALL, the writes are posted using WRITE_SYNC_PLUG; this
- * causes the writes to be flagged as synchronous writes, but the
- * block device queue will NOT be unplugged, since usually many pages
- * will be pushed to the out before the higher-level caller actually
- * waits for the writes to be completed. The various wait functions,
- * such as wait_on_writeback_range() will ultimately call sync_page()
- * which will ultimately call blk_run_backing_dev(), which will end up
- * unplugging the device queue.
+ * WB_SYNC_ALL, the writes are posted using WRITE_SYNC; this
+ * causes the writes to be flagged as synchronous writes.
+ * The various wait functions, such as wait_on_writeback_range() will
+ * ultimately call sync_page() which will ultimately call
+ * blk_run_backing_dev(), which will end up unplugging the device queue.
*/
static int __block_write_full_page(struct inode *inode, struct page *page,
get_block_t *get_block, struct writeback_control *wbc,
@@ -1622,7 +1619,7 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
const unsigned blocksize = 1 << inode->i_blkbits;
int nr_underway = 0;
int write_op = (wbc->sync_mode == WB_SYNC_ALL ?
- WRITE_SYNC_PLUG : WRITE);
+ WRITE_SYNC : WRITE);
BUG_ON(!PageLocked(page));
diff --git a/fs/direct-io.c b/fs/direct-io.c
index df709b3..4260831 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -1173,7 +1173,7 @@ __blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
struct dio *dio;
if (rw & WRITE)
- rw = WRITE_ODIRECT_PLUG;
+ rw = WRITE_ODIRECT;
if (bdev)
bdev_blkbits = blksize_bits(bdev_logical_block_size(bdev));
diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
index 955cc30..e2cd90e 100644
--- a/fs/ext4/page-io.c
+++ b/fs/ext4/page-io.c
@@ -310,8 +310,7 @@ static int io_submit_init(struct ext4_io_submit *io,
io_end->offset = (page->index << PAGE_CACHE_SHIFT) + bh_offset(bh);
io->io_bio = bio;
- io->io_op = (wbc->sync_mode == WB_SYNC_ALL ?
- WRITE_SYNC_PLUG : WRITE);
+ io->io_op = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
io->io_next_block = bh->b_blocknr;
return 0;
}
diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c
index eb01f35..7f1c112 100644
--- a/fs/gfs2/log.c
+++ b/fs/gfs2/log.c
@@ -121,7 +121,7 @@ __acquires(&sdp->sd_log_lock)
lock_buffer(bh);
if (test_clear_buffer_dirty(bh)) {
bh->b_end_io = end_buffer_write_sync;
- submit_bh(WRITE_SYNC_PLUG, bh);
+ submit_bh(WRITE_SYNC, bh);
} else {
unlock_buffer(bh);
brelse(bh);
@@ -647,7 +647,7 @@ static void gfs2_ordered_write(struct gfs2_sbd *sdp)
lock_buffer(bh);
if (buffer_mapped(bh) && test_clear_buffer_dirty(bh)) {
bh->b_end_io = end_buffer_write_sync;
- submit_bh(WRITE_SYNC_PLUG, bh);
+ submit_bh(WRITE_SYNC, bh);
} else {
unlock_buffer(bh);
brelse(bh);
diff --git a/fs/gfs2/lops.c b/fs/gfs2/lops.c
index bf33f82..48b545a 100644
--- a/fs/gfs2/lops.c
+++ b/fs/gfs2/lops.c
@@ -200,7 +200,7 @@ static void buf_lo_before_commit(struct gfs2_sbd *sdp)
}
gfs2_log_unlock(sdp);
- submit_bh(WRITE_SYNC_PLUG, bh);
+ submit_bh(WRITE_SYNC, bh);
gfs2_log_lock(sdp);
n = 0;
@@ -210,7 +210,7 @@ static void buf_lo_before_commit(struct gfs2_sbd *sdp)
gfs2_log_unlock(sdp);
lock_buffer(bd2->bd_bh);
bh = gfs2_log_fake_buf(sdp, bd2->bd_bh);
- submit_bh(WRITE_SYNC_PLUG, bh);
+ submit_bh(WRITE_SYNC, bh);
gfs2_log_lock(sdp);
if (++n >= num)
break;
@@ -352,7 +352,7 @@ static void revoke_lo_before_commit(struct gfs2_sbd *sdp)
sdp->sd_log_num_revoke--;
if (offset + sizeof(u64) > sdp->sd_sb.sb_bsize) {
- submit_bh(WRITE_SYNC_PLUG, bh);
+ submit_bh(WRITE_SYNC, bh);
bh = gfs2_log_get_buf(sdp);
mh = (struct gfs2_meta_header *)bh->b_data;
@@ -369,7 +369,7 @@ static void revoke_lo_before_commit(struct gfs2_sbd *sdp)
}
gfs2_assert_withdraw(sdp, !sdp->sd_log_num_revoke);
- submit_bh(WRITE_SYNC_PLUG, bh);
+ submit_bh(WRITE_SYNC, bh);
}
static void revoke_lo_before_scan(struct gfs2_jdesc *jd,
@@ -571,7 +571,7 @@ static void gfs2_write_blocks(struct gfs2_sbd *sdp, struct buffer_head *bh,
ptr = bh_log_ptr(bh);
get_bh(bh);
- submit_bh(WRITE_SYNC_PLUG, bh);
+ submit_bh(WRITE_SYNC, bh);
gfs2_log_lock(sdp);
while(!list_empty(list)) {
bd = list_entry(list->next, struct gfs2_bufdata, bd_le.le_list);
@@ -597,7 +597,7 @@ static void gfs2_write_blocks(struct gfs2_sbd *sdp, struct buffer_head *bh,
} else {
bh1 = gfs2_log_fake_buf(sdp, bd->bd_bh);
}
- submit_bh(WRITE_SYNC_PLUG, bh1);
+ submit_bh(WRITE_SYNC, bh1);
gfs2_log_lock(sdp);
ptr += 2;
}
diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c
index a566331..867b713 100644
--- a/fs/gfs2/meta_io.c
+++ b/fs/gfs2/meta_io.c
@@ -37,7 +37,7 @@ static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wb
struct buffer_head *bh, *head;
int nr_underway = 0;
int write_op = REQ_META |
- (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC_PLUG : WRITE);
+ (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE);
BUG_ON(!PageLocked(page));
BUG_ON(!page_has_buffers(page));
diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
index 34a4861..66be299 100644
--- a/fs/jbd/commit.c
+++ b/fs/jbd/commit.c
@@ -333,7 +333,7 @@ void journal_commit_transaction(journal_t *journal)
* instead we rely on sync_buffer() doing the unplug for us.
*/
if (commit_transaction->t_synchronous_commit)
- write_op = WRITE_SYNC_PLUG;
+ write_op = WRITE_SYNC;
spin_lock(&commit_transaction->t_handle_lock);
while (commit_transaction->t_updates) {
DEFINE_WAIT(wait);
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index f3ad159..3da1cc4 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -137,9 +137,9 @@ static int journal_submit_commit_record(journal_t *journal,
if (journal->j_flags & JBD2_BARRIER &&
!JBD2_HAS_INCOMPAT_FEATURE(journal,
JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT))
- ret = submit_bh(WRITE_SYNC_PLUG | WRITE_FLUSH_FUA, bh);
+ ret = submit_bh(WRITE_SYNC | WRITE_FLUSH_FUA, bh);
else
- ret = submit_bh(WRITE_SYNC_PLUG, bh);
+ ret = submit_bh(WRITE_SYNC, bh);
*cbh = bh;
return ret;
@@ -369,7 +369,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
* instead we rely on sync_buffer() doing the unplug for us.
*/
if (commit_transaction->t_synchronous_commit)
- write_op = WRITE_SYNC_PLUG;
+ write_op = WRITE_SYNC;
trace_jbd2_commit_locking(journal, commit_transaction);
stats.run.rs_wait = commit_transaction->t_max_wait;
stats.run.rs_locked = jiffies;
diff --git a/fs/nilfs2/segbuf.c b/fs/nilfs2/segbuf.c
index 0f83e93..2853ff2 100644
--- a/fs/nilfs2/segbuf.c
+++ b/fs/nilfs2/segbuf.c
@@ -509,7 +509,7 @@ static int nilfs_segbuf_write(struct nilfs_segment_buffer *segbuf,
* Last BIO is always sent through the following
* submission.
*/
- rw |= REQ_SYNC | REQ_UNPLUG;
+ rw |= REQ_SYNC;
res = nilfs_segbuf_submit_bio(segbuf, &wi, rw);
}
diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c
index 83c1c20..6bbb0ee 100644
--- a/fs/xfs/linux-2.6/xfs_aops.c
+++ b/fs/xfs/linux-2.6/xfs_aops.c
@@ -413,8 +413,7 @@ xfs_submit_ioend_bio(
if (xfs_ioend_new_eof(ioend))
xfs_mark_inode_dirty(XFS_I(ioend->io_inode));
- submit_bio(wbc->sync_mode == WB_SYNC_ALL ?
- WRITE_SYNC_PLUG : WRITE, bio);
+ submit_bio(wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE, bio);
}
STATIC struct bio *
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 16b2864..be50d9e 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -128,7 +128,6 @@ enum rq_flag_bits {
__REQ_NOIDLE, /* don't anticipate more IO after this one */
/* bio only flags */
- __REQ_UNPLUG, /* unplug the immediately after submission */
__REQ_RAHEAD, /* read ahead, can fail anytime */
__REQ_THROTTLED, /* This bio has already been subjected to
* throttling rules. Don't do it again. */
@@ -172,7 +171,6 @@ enum rq_flag_bits {
REQ_NOIDLE | REQ_FLUSH | REQ_FUA)
#define REQ_CLONE_MASK REQ_COMMON_MASK
-#define REQ_UNPLUG (1 << __REQ_UNPLUG)
#define REQ_RAHEAD (1 << __REQ_RAHEAD)
#define REQ_THROTTLED (1 << __REQ_THROTTLED)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 9f2cf69..543e226 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -135,16 +135,10 @@ struct inodes_stat_t {
* block layer could (in theory) choose to ignore this
* request if it runs into resource problems.
* WRITE A normal async write. Device will be plugged.
- * WRITE_SYNC_PLUG Synchronous write. Identical to WRITE, but passes down
+ * WRITE_SYNC Synchronous write. Identical to WRITE, but passes down
* the hint that someone will be waiting on this IO
- * shortly. The device must still be unplugged explicitly,
- * WRITE_SYNC_PLUG does not do this as we could be
- * submitting more writes before we actually wait on any
- * of them.
- * WRITE_SYNC Like WRITE_SYNC_PLUG, but also unplugs the device
- * immediately after submission. The write equivalent
- * of READ_SYNC.
- * WRITE_ODIRECT_PLUG Special case write for O_DIRECT only.
+ * shortly. The write equivalent of READ_SYNC.
+ * WRITE_ODIRECT Special case write for O_DIRECT only.
* WRITE_FLUSH Like WRITE_SYNC but with preceding cache flush.
* WRITE_FUA Like WRITE_SYNC but data is guaranteed to be on
* non-volatile media on completion.
@@ -160,18 +154,14 @@ struct inodes_stat_t {
#define WRITE RW_MASK
#define READA RWA_MASK
-#define READ_SYNC (READ | REQ_SYNC | REQ_UNPLUG)
+#define READ_SYNC (READ | REQ_SYNC)
#define READ_META (READ | REQ_META)
-#define WRITE_SYNC_PLUG (WRITE | REQ_SYNC | REQ_NOIDLE)
-#define WRITE_SYNC (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_UNPLUG)
-#define WRITE_ODIRECT_PLUG (WRITE | REQ_SYNC)
+#define WRITE_SYNC (WRITE | REQ_SYNC | REQ_NOIDLE)
+#define WRITE_ODIRECT (WRITE | REQ_SYNC)
#define WRITE_META (WRITE | REQ_META)
-#define WRITE_FLUSH (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_UNPLUG | \
- REQ_FLUSH)
-#define WRITE_FUA (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_UNPLUG | \
- REQ_FUA)
-#define WRITE_FLUSH_FUA (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_UNPLUG | \
- REQ_FLUSH | REQ_FUA)
+#define WRITE_FLUSH (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH)
+#define WRITE_FUA (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FUA)
+#define WRITE_FLUSH_FUA (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH | REQ_FUA)
#define SEL_IN 1
#define SEL_OUT 2
diff --git a/kernel/power/block_io.c b/kernel/power/block_io.c
index 83bbc7c..d09dd10 100644
--- a/kernel/power/block_io.c
+++ b/kernel/power/block_io.c
@@ -28,7 +28,7 @@
static int submit(int rw, struct block_device *bdev, sector_t sector,
struct page *page, struct bio **bio_chain)
{
- const int bio_rw = rw | REQ_SYNC | REQ_UNPLUG;
+ const int bio_rw = rw | REQ_SYNC;
struct bio *bio;
bio = bio_alloc(__GFP_WAIT | __GFP_HIGH, 1);
diff --git a/mm/page_io.c b/mm/page_io.c
index 2dee975..dc76b4d 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -106,7 +106,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
goto out;
}
if (wbc->sync_mode == WB_SYNC_ALL)
- rw |= REQ_SYNC | REQ_UNPLUG;
+ rw |= REQ_SYNC;
count_vm_event(PSWPOUT);
set_page_writeback(page);
unlock_page(page);
--
Jens Axboe
On Tue, Mar 08, 2011 at 01:38:08PM +0100, Jens Axboe wrote:
> -#define DP_UNPLUG 8 /* equals REQ_UNPLUG */
> +#define DP_UNPLUG 8 /* not used anymore */
The way this is used might need some more review. It seems like DRBD is
trying to propagate unplug requests over the wire, which is
functionality we lose now.
> + * The various wait functions, such as wait_on_writeback_range() will
> + * ultimately call sync_page() which will ultimately call
> + * blk_run_backing_dev(), which will end up unplugging the device queue.
This comment describes code that doesn't exist anymore on your branch.
On 2011-03-09 11:38, [email protected] wrote:
> On Tue, Mar 08, 2011 at 01:38:08PM +0100, Jens Axboe wrote:
>> -#define DP_UNPLUG 8 /* equals REQ_UNPLUG */
>> +#define DP_UNPLUG 8 /* not used anymore */
>
> The way this is used might need some more review. It seems like DRBD is
> trying to propagate unplug requests over the wire, which is
> functionality we lose now.
But that use case is pretty questionable. The receiving end should just
do its own plugging, if it's beneficial.
>> + * The various wait functions, such as wait_on_writeback_range() will
>> + * ultimately call sync_page() which will ultimately call
>> + * blk_run_backing_dev(), which will end up unplugging the device queue.
>
> This comment describes code that doesn't exist anymore on your branch.
Thanks, I'll kill those.
--
Jens Axboe