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On enable, initialize the io_alloc CLOSID with all > usable CBMs across all the domains. > > Since CLOSIDs are managed by resctrl fs, it is least invasive to make > "io_alloc is supported by maximum supported CLOSID" part of the initial > resctrl fs support for io_alloc. Take care to minimally (only in error > messages) expose this use of CLOSID for io_alloc to user space so that this > is not required from other architectures that may support io_alloc > differently in the future. > > When resctrl is mounted with "-o cdp" to enable code/data prioritization, > there are two L3 resources that can support I/O allocation: L3CODE and > L3DATA. From resctrl fs perspective the two resources share a CLOSID and > the architecture's available CLOSID are halved to support this. The > architecture's underlying CLOSID used by SDCIAE when CDP is enabled is the > CLOSID associated with the CDP_CODE resource, but from resctrl's perspective > there is only one CLOSID for both CDP_CODE and CDP_DATA. CDP_DATA is thus > not usable for general (CPU) cache allocation nor I/O allocation. Keep the > CDP_CODE and CDP_DATA I/O alloc status in sync to avoid any confusion to > user space. That is, enabling io_alloc on CDP_CODE does so on CDP_DATA and > vice-versa, and keep the I/O allocation CBMs of CDP_CODE and CDP_DATA in > sync. > > Signed-off-by: Babu Moger > --- > v12: Minor format fix in resctrl.rst. > Added text about writable files in the info section. > Removed Reviewed-by tag from Reinette as there are some new text changes from Dave. Only this patch needs "Reviewed-by" tag. Gentle reminder with upcoming holidays. Hoping this series will be queued for next merge window. Thanks Babu