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path: root/include/linux/dm-kcopyd.h
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2011-10-31dm kcopyd: add dm_kcopyd_zero to zero an areaMikulas Patocka
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 <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-08-02dm snapshot: skip reading origin when overwriting complete chunkMikulas Patocka
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 <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-05-29dm kcopyd: return client directly and not through a pointerMikulas Patocka
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 <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-05-29dm kcopyd: reserve fewer pagesMikulas Patocka
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 <mpatocka@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2008-04-25dm: move include filesAlasdair G Kergon
Publish the dm-io, dm-log and dm-kcopyd headers in include/linux. Signed-off-by: Alasdair G Kergon <agk@redhat.com>