From 95d402f057f2e208e4631893f6cd4a59c7c05e41 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Mon, 31 Oct 2011 20:19:09 +0000 Subject: 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 Signed-off-by: Alasdair G Kergon --- drivers/md/Kconfig | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'drivers/md/Kconfig') diff --git a/drivers/md/Kconfig b/drivers/md/Kconfig index f75a66e..b1a9214 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 -- cgit v1.1