BFQ now shares interface files with CFQ, for the proportional-share policy. Make documentation consistent with that. Signed-off-by: Paolo Valente <paolo.valente@xxxxxxxxxx> --- Documentation/block/bfq-iosched.txt | 28 +++++++++++++++------------- 1 file changed, 15 insertions(+), 13 deletions(-) diff --git a/Documentation/block/bfq-iosched.txt b/Documentation/block/bfq-iosched.txt index 6d7dd5ab8554..3d7ef138ce6a 100644 --- a/Documentation/block/bfq-iosched.txt +++ b/Documentation/block/bfq-iosched.txt @@ -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. -- 2.16.1
