Modified ata_eh_request_sense(), instead of taking an extra parameter, Added a new patch (10/18) that removes unnecessary !cmd checks. Improved commit message for patch "block: introduce duration-limits priority Renamed flag SCMD_EH_SUCCESS_CMD to SCMD_FORCE_EH_SUCCESS. Dropped extern keyword when modifying SCSI function declarations. Reordered the patches by subsystem, so that the different subsystem maintainersĬan pick up a single range of patches to their respective tree. Time, so you currently need to recompile QEMU when switching between policies.)įor further information about CDL, see Damien's slides: (NOTE: the QEMU implementation requires you to define the CDL policy at compile We also provide a CDL test suite located in the cdl-tools repo, see: Timeout, the I/O will result in a -ETIME error to user-space. Regardless of the CDL policy, in case of a CDL With the following fio patch that simply adds the new priority class:įio -ioengine=io_uring -cmdprio_percentage=10 -cmdprio_class=4 -cmdprio=DLD_indexĪ simple way to test is to use a DLD with a very short duration limit,Īnd send large reads. Per AIO (io_uring sqe->ioprio or libaio iocb->aio_reqprio) or per-thread When using this class, the existing I/O priority levels (0-7) directlyīy reusing the I/O priority API, the user can both define DLD to use ![]() This means that we introduce a new priority class (IOPRIO_CLASS_DL). We have decided to reuse the I/O priority API. In order for user-space to be able to select a specific DLD for an I/O, (see ncq_prio_enable and sas_ncq_prio_enable inĭocumentation/ABI/testing/sysfs-block-device),Įcho 1 > /sys/block/$bdev/device/duration_limits/enable ![]() Since CDL is mutually exclusive with NCQ priority So using a user-space application that sends passthrough commands, If a user really wants to change the descriptors, they can do The DLDs are defined in the CDL log page(s) and are readable and writable.įor convenience, the kernel provides a sysfs interface for reading theĭescriptors. Regardless of the CDL policy, in case of a CDL timeout, the I/O will Note that the command will not have transferred anyĭata to/from the device when the command timed out, even though the Policy 0xD (complete-unavailable), command will be completed withoutĮrror (ATA) or status GOOD (SCSI), with sense data indicating that theĬommand timed out. (ATA) or status CHECK CONDITION (SCSI), with sense data indicating that Policy 0xF (abort), command will be completed with command aborted error The DLD index points to one of the 7 DLDs.ĭLD index 0 means no descriptor, so no limit.Ī DLD can have a few different policies, but the two major ones are: The DLD index field (3 bits, so 0-7) in the command itself. ![]() Simply put, a DLD contains a limit and a policy.Ī command can specify that a certain limit should be applied by setting (a simpler version of CDL is defined in T10 SPC-5).ĬDL defines Duration Limits Descriptors (DLD).ħ DLDs for read commands and 7 DLDs for write commands. T10 SCSI Primary Commands - 6 (SPC-6) respectively The series is based on linux-next tag: next-20230124 This series adds support for Command Duration Limits. Bottomley,Ĭc: Christoph Hellwig, Hannes Reinecke, linux-scsi, linux-ide, To: Paolo Valente, Jens Axboe, Damien Le Moal, James E.J. ![]() ` (17 more replies) 0 siblings, 18 replies 82+ messages in threadįrom: Niklas Cassel 19:02 UTC ( / raw) 19:02 ` block: introduce duration-limits priority class Niklas Cassel Add Command Duration Limits support Linux-Block Archive on help / color / mirror / Atom feed * Add Command Duration Limits support 19:02 Niklas Cassel
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