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path: root/drivers/md/persistent-data/dm-space-map.h
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2021-06-04dm space maps: improve performance with inc/dec on ranges of blocksJoe Thornber
When we break sharing on btree nodes we typically need to increment the reference counts to every value held in the node. This can cause a lot of repeated calls to the space maps. Fix this by changing the interface to the space map inc/dec methods to take ranges of adjacent blocks to be operated on. For installations that are using a lot of snapshots this will reduce cpu overhead of fundamental operations such as provisioning a new block, or deleting a snapshot, by as much as 10 times. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2013-05-10dm persistent data: add threshold callback to space mapJoe Thornber
Add a threshold callback function to the persistent data space map interface for a subsequent patch to use. dm-thin and dm-cache are interested in knowing when they're getting low on metadata or data blocks. This patch introduces a new method for registering a callback against a threshold. Signed-off-by: Joe Thornber <ejt@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
2011-10-31dm: add persistent data libraryJoe Thornber
The persistent-data library offers a re-usable framework for the storage and management of on-disk metadata in device-mapper targets. It's used by the thin-provisioning target in the next patch and in an upcoming hierarchical storage target. For further information, please read Documentation/device-mapper/persistent-data.txt Signed-off-by: Joe Thornber <thornber@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com> Signed-off-by: Alasdair G Kergon <agk@redhat.com>