dm: change "unsigned" to "unsigned int"

Signed-off-by: Heinz Mauelshagen <[email protected]>
Signed-off-by: Mike Snitzer <[email protected]>

dm: add missing SPDX-License-Indentifiers

'GPL-2.0-only' is used instead of 'GPL-2.0' because SPDX has
deprecated its use.

Suggested-by: John Wiele <[email protected]>
Signed-off-by: Heinz Mauelsha

dm: add missing SPDX-License-Indentifiers

'GPL-2.0-only' is used instead of 'GPL-2.0' because SPDX has
deprecated its use.

Suggested-by: John Wiele <[email protected]>
Signed-off-by: Heinz Mauelshagen <[email protected]>
Signed-off-by: Mike Snitzer <[email protected]>

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dm writecache: have ssd writeback wait if the kcopyd workqueue is busy

Make dm-writecache wait if the kcopyd workqueue is busy (as will
happen if waiting for page allocation or inside submit_bio).

dm writecache: have ssd writeback wait if the kcopyd workqueue is busy

Make dm-writecache wait if the kcopyd workqueue is busy (as will
happen if waiting for page allocation or inside submit_bio).

This change improves performance of "mkfs.ext2" by approximately 20%
on one testbed.

Signed-off-by: Mikulas Patocka <[email protected]>
Signed-off-by: Mike Snitzer <[email protected]>

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dm kcopyd: return void from dm_kcopyd_copy()

dm_kcopyd_copy() only ever returns 0 so there is no need for callers to
account for possible failure. Same goes for dm_kcopyd_zero().

Signed-off-by: Mi

dm kcopyd: return void from dm_kcopyd_copy()

dm_kcopyd_copy() only ever returns 0 so there is no need for callers to
account for possible failure. Same goes for dm_kcopyd_zero().

Signed-off-by: Mike Snitzer <[email protected]>

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dm kcopyd: add sequential write feature

When copyying blocks to host-managed zoned block devices, writes must be
sequential. However, dm_kcopyd_copy() does not guarantee this as writes
are issued i

dm kcopyd: add sequential write feature

When copyying blocks to host-managed zoned block devices, writes must be
sequential. However, dm_kcopyd_copy() does not guarantee this as writes
are issued in the completion order of reads, and reads may complete out
of order despite being issued sequentially.

Fix this by introducing the DM_KCOPYD_WRITE_SEQ feature flag. This can
be specified when calling dm_kcopyd_copy() and should be set
automatically if one of the destinations is a host-managed zoned block
device. For a split job, the master job maintains the write position at
which writes must be issued. This is checked with the pop() function
which is modified to not return any write I/O sub job that is not at the
correct write position.

When DM_KCOPYD_WRITE_SEQ is specified for a job, errors cannot be
ignored and the flag DM_KCOPYD_IGNORE_ERROR is ignored, even if
specified by the user.

Signed-off-by: Damien Le Moal <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Reviewed-by: Bart Van Assche <[email protected]>
Signed-off-by: Mike Snitzer <[email protected]>

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dm kcopyd: introduce configurable throttling

This patch allows the administrator to reduce the rate at which kcopyd
issues I/O.

Each module that uses kcopyd acquires a throttle parameter that can b

dm kcopyd: introduce configurable throttling

This patch allows the administrator to reduce the rate at which kcopyd
issues I/O.

Each module that uses kcopyd acquires a throttle parameter that can be
set in /sys/module/*/parameters.

We maintain a history of kcopyd usage by each module in the variables
io_period and total_period in struct dm_kcopyd_throttle. The actual
kcopyd activity is calculated as a percentage of time equal to
"(100 * io_period / total_period)". This is compared with the user-defined
throttle percentage threshold and if it is exceeded, we sleep.

Signed-off-by: Mikulas Patocka <[email protected]>
Signed-off-by: Alasdair G Kergon <[email protected]>

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dm kcopyd: add dm_kcopyd_zero to zero an area

This patch introduces dm_kcopyd_zero() to make it easy to use
kcopyd to write zeros into the requested areas instead
instead of copying. It is implemen

dm kcopyd: add dm_kcopyd_zero to zero an area

This patch introduces dm_kcopyd_zero() to make it easy to use
kcopyd to write zeros into the requested areas instead
instead of copying. It is implemented by passing a NULL
copying source to dm_kcopyd_copy().

The forthcoming thin provisioning target uses this.

Signed-off-by: Mikulas Patocka <[email protected]>
Signed-off-by: Alasdair G Kergon <[email protected]>

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dm snapshot: skip reading origin when overwriting complete chunk

If we write a full chunk in the snapshot, skip reading the origin device
because the whole chunk will be overwritten anyway.

This pa

dm snapshot: skip reading origin when overwriting complete chunk

If we write a full chunk in the snapshot, skip reading the origin device
because the whole chunk will be overwritten anyway.

This patch changes the snapshot write logic when a full chunk is written.
In this case:
1. allocate the exception
2. dispatch the bio (but don't report the bio completion to device mapper)
3. write the exception record
4. report bio completed

Callbacks must be done through the kcopyd thread, because callbacks must not
race with each other. So we create two new functions:

dm_kcopyd_prepare_callback: allocate a job structure and prepare the callback.
(This function must not be called from interrupt context.)

dm_kcopyd_do_callback: submit callback.
(This function may be called from interrupt context.)

Performance test (on snapshots with 4k chunk size):
without the patch:
non-direct-io sequential write (dd): 17.7MB/s
direct-io sequential write (dd): 20.9MB/s
non-direct-io random write (mkfs.ext2): 0.44s

with the patch:
non-direct-io sequential write (dd): 26.5MB/s
direct-io sequential write (dd): 33.2MB/s
non-direct-io random write (mkfs.ext2): 0.27s

Signed-off-by: Mikulas Patocka <[email protected]>
Signed-off-by: Alasdair G Kergon <[email protected]>

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dm kcopyd: return client directly and not through a pointer

Return client directly from dm_kcopyd_client_create, not through a
parameter, making it consistent with dm_io_client_create.

Signed-off-b

dm kcopyd: return client directly and not through a pointer

Return client directly from dm_kcopyd_client_create, not through a
parameter, making it consistent with dm_io_client_create.

Signed-off-by: Mikulas Patocka <[email protected]>
Signed-off-by: Alasdair G Kergon <[email protected]>

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dm kcopyd: reserve fewer pages

Reserve just the minimum of pages needed to process one job.

Because we allocate pages from page allocator, we don't need to reserve
a large number of pages. The max

dm kcopyd: reserve fewer pages

Reserve just the minimum of pages needed to process one job.

Because we allocate pages from page allocator, we don't need to reserve
a large number of pages. The maximum job size is SUB_JOB_SIZE and we
calculate the number of reserved pages based on this.

Signed-off-by: Mikulas Patocka <[email protected]>
Signed-off-by: Alasdair G Kergon <[email protected]>

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dm: move include files

Publish the dm-io, dm-log and dm-kcopyd headers in include/linux.

Signed-off-by: Alasdair G Kergon <[email protected]>