The document of blkio-cgroup. Signed-off-by: Hirokazu Takahashi <taka@xxxxxxxxxxxxx> Signed-off-by: Ryo Tsuruta <ryov@xxxxxxxxxxxxx> --- Documentation/cgroups/00-INDEX | 2 + Documentation/cgroups/blkio.txt | 49 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 51 insertions(+) Index: linux-2.6.31-rc7/Documentation/cgroups/00-INDEX =================================================================== --- linux-2.6.31-rc7.orig/Documentation/cgroups/00-INDEX +++ linux-2.6.31-rc7/Documentation/cgroups/00-INDEX @@ -16,3 +16,5 @@ memory.txt - Memory Resource Controller; design, accounting, interface, testing. resource_counter.txt - Resource Counter API. +blkio.txt + - Block I/O Tracking; description, interface and examples. Index: linux-2.6.31-rc7/Documentation/cgroups/blkio.txt =================================================================== --- /dev/null +++ linux-2.6.31-rc7/Documentation/cgroups/blkio.txt @@ -0,0 +1,49 @@ +Block I/O Cgroup + +1. Overview + +Using this feature the owners of any type of I/O can be determined. +This allows dm-ioband to control block I/O bandwidth even when it is +accepting delayed write requests. dm-ioband can find the cgroup of +each request. It is also for possible that others working on I/O +bandwidth throttling to use this functionality to control asynchronous +I/O with a little enhancement. + +2. Setting up blkio-cgroup + +The following kernel config options are required. + +CONFIG_CGROUPS=y +CONFIG_CGROUP_BLKIO=y + +Selecting the options for the cgroup memory subsystem is also recommended +as it makes it possible to give some I/O bandwidth and memory to a selected +cgroup to control delayed write requests. The amount of dirty pages is +limited within the cgroup even if the allocated bandwidth is narrow. + +CONFIG_RESOURCE_COUNTERS=y +CONFIG_CGROUP_MEM_RES_CTLR=y + +3. User interface + +3.1 Mounting the cgroup filesystem + +First, mount the cgroup filesystem in order to enable observation and +modification of the blkio-cgroup settings. + +# mount -t cgroup -o blkio none /cgroup + +3.2 The blkio.id file + +After mounting the cgroup filesystem the blkio.id file will be visible +in the cgroup directory. This file contains a unique ID number for +each cgroup. When an I/O operation starts, blkio-cgroup sets the +page's ID number on the page cgroup. The cgroup of I/O can be +determined by retrieving the ID number from the page cgroup, because +the page cgroup is associated with the page which is involved in the +I/O. + +4. Contact + +Linux Block I/O Bandwidth Control Project +http://sourceforge.net/projects/ioband/ -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
