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authorMikulas Patocka <mpatocka@redhat.com>2011-10-31 20:19:09 +0000
committerAlasdair G Kergon <agk@redhat.com>2011-10-31 20:19:09 +0000
commit95d402f057f2e208e4631893f6cd4a59c7c05e41 (patch)
tree4edb6c01f62689617ee3098104c135ef2c43f0e2 /drivers/md/Kconfig
parent3cf2e4ba74ca1bf5d8ad26cd18592f02b32964f5 (diff)
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/Kconfig8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig
index f75a66e7d31..b1a92149704 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