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| author | Mikulas Patocka <mpatocka@redhat.com> | 2011-10-31 20:19:09 +0000 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2011-10-31 20:19:09 +0000 |
| commit | 95d402f057f2e208e4631893f6cd4a59c7c05e41 (patch) | |
| tree | 4edb6c01f62689617ee3098104c135ef2c43f0e2 /drivers/md/Kconfig | |
| parent | 3cf2e4ba74ca1bf5d8ad26cd18592f02b32964f5 (diff) | |
| download | lwn-95d402f057f2e208e4631893f6cd4a59c7c05e41.tar.gz lwn-95d402f057f2e208e4631893f6cd4a59c7c05e41.zip | |
dm: add bufio
The dm-bufio interface allows you to do cached I/O on devices,
holding recently-read blocks in memory and performing delayed writes.
We don't use buffer cache or page cache already present in the kernel, because:
* we need to handle block sizes larger than a page
* we can't allocate memory to perform reads or we'd have deadlocks
Currently, when a cache is required, we limit its size to a fraction of
available memory. Usage can be viewed and changed in
/sys/module/dm_bufio/parameters/ .
The first user is thin provisioning, but more dm users are planned.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md/Kconfig')
| -rw-r--r-- | drivers/md/Kconfig | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index f75a66e7d312..b1a921497043 100644 --- a/drivers/md/Kconfig +++ b/drivers/md/Kconfig @@ -208,6 +208,14 @@ config DM_DEBUG If unsure, say N. +config DM_BUFIO + tristate + depends on BLK_DEV_DM && EXPERIMENTAL + ---help--- + This interface allows you to do buffered I/O on a device and acts + as a cache, holding recently-read blocks in memory and performing + delayed writes. + config DM_CRYPT tristate "Crypt target support" depends on BLK_DEV_DM |