@@ -508,12 +508,14 @@ process.
To get proportional sharing of bandwidth with BFQ for a given device,
BFQ must of course be the active scheduler for that device.
-Within each group directory, the names of the files associated with
-BFQ-specific cgroup parameters and stats begin with the "bfq."
-prefix. So, with cgroups-v1 or cgroups-v2, the full prefix for
-BFQ-specific files is "blkio.bfq." or "io.bfq." For example, the group
-parameter to set the weight of a group with BFQ is blkio.bfq.weight
-or io.bfq.weight.
+BFQ uses the standard interface files of the proportional-share
+policy, previously used by CFQ. If one such file is read/written, then
+the operation associated with the file is performed by BFQ for each
+device where BFQ is the active scheduler. In addition, BFQ is
+configured so as to share interface files with other entities (if some
+of these files does happen to be shared, then its associated operation
+is performed also by any of the other entities that is using the
+file).
As for cgroups-v1 (blkio controller), the exact set of stat files
created, and kept up-to-date by bfq, depends on whether
@@ -521,13 +523,13 @@ CONFIG_DEBUG_BLK_CGROUP is set. If it is set, then bfq creates all
the stat files documented in
Documentation/cgroup-v1/blkio-controller.txt. If, instead,
CONFIG_DEBUG_BLK_CGROUP is not set, then bfq creates only the files
-blkio.bfq.io_service_bytes
-blkio.bfq.io_service_bytes_recursive
-blkio.bfq.io_serviced
-blkio.bfq.io_serviced_recursive
+blkio.io_service_bytes
+blkio.io_service_bytes_recursive
+blkio.io_serviced
+blkio.io_serviced_recursive
The value of CONFIG_DEBUG_BLK_CGROUP greatly influences the maximum
-throughput sustainable with bfq, because updating the blkio.bfq.*
+throughput sustainable with BFQ, because updating the blkio.*
stats is rather costly, especially for some of the stats enabled by
CONFIG_DEBUG_BLK_CGROUP.
@@ -536,8 +538,8 @@ Parameters to set
For each group, there is only the following parameter to set.
-weight (namely blkio.bfq.weight or io.bfq-weight): the weight of the
-group inside its parent. Available values: 1..10000 (default 100). The
+weight (namely blkio.weight or io.weight): the weight of the group
+inside its parent. Available values: 1..10000 (default 100). The
linear mapping between ioprio and weights, described at the beginning
of the tunable section, is still valid, but all weights higher than
IOPRIO_BE_NR*10 are mapped to ioprio 0.
BFQ now shares interface files with CFQ, for the proportional-share policy. Make documentation consistent with that. Signed-off-by: Paolo Valente <paolo.valente@linaro.org> --- Documentation/block/bfq-iosched.txt | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) -- 2.16.1