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Get the max CLOSID and verify if the CLOSID is available. >> + * >> + * The total number of CLOSIDs is determined in closid_init(), based on the >> + * minimum supported across all resources. If CDP (Code Data Prioritization) >> + * is enabled, the number of CLOSIDs is halved. The final value is returned >> + * by closids_supported(). Make sure this value aligns with the maximum >> + * CLOSID supported by the respective resource. >> + */ >> +static int resctrl_io_alloc_closid_get(struct rdt_resource *r) >> +{ >> + int num_closids = closids_supported(); >> + >> + if (resctrl_arch_get_cdp_enabled(r->rid)) >> + num_closids *= 2; >> + >> + if (num_closids != resctrl_arch_get_num_closid(r)) >> + return -ENOSPC; >> + >> + return closids_supported() - 1; >> +} > > Is using closids_supported() the right thing here? That's > the minimum value across all resources. So suppose you had > 16 CLOS for the L3 resource, but only 8 CLOS in one of L2/MB/SMBA. > > I'd assume the your h/w doesn't care that Linux chose to > ignore half of the available L3 CLOSIDs, and is still going > to use CLOSID==15 for SDCIA. > > I think you'll take the -ENOSPC error return. But do you > really need to do that? Maybe you can still have SDCIA > enabled and using CLOSID 15? We cannot support more than closids_supported(), as the bitmaps are not initialized beyond that point, and other routines are also not designed to handle more than closid_free_map_len. While it's technically possible to implement a workaround for this special case, it would be a hacky solution. It's likely unnecessary to go down that path. Thanks Babu