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Both the generic resctrl >> code and the architecture layer need a single shared snapshot of the >> supported and effective policy plus the resource group that backs the >> global-assign modes; that snapshot is struct resctrl_kmode_cfg. > > This does not seem to match implementation since this implementation does > not actually share struct resctrl_kmode_cfg as described above. Only > resctrl_arch_get_kmode_support() exchanges this struct between fs and > arch and as already mentioned that usage looks unnecessary. The other > arch/fs touch points use either individual members or their properties > (like closid/rmid). > > As described in response to previous patch I think this can be simplified > while also making it more robust. > Ack. >> >> Add the file-local resctrl_kcfg and a helper resctrl_kmode_init() that: >> >> - Adds kmode and kmode_cur with BIT(INHERIT_CTRL_AND_MON), the >> universally supported mode and today's behaviour; >> - points k_rdtgrp at rdtgroup_default so global-assign modes have a >> valid backing group from boot; > > If the default mode is INHERIT_CTRL_AND_MON then should the default group > not be NULL? It will be initialized to NULL. > >> - calls resctrl_arch_get_kmode_support() so each architecture ORs >> BIT() into kmode for the policies its hardware supports >> (on x86, AMD PLZA contributes the two global-assign modes). >> >> resctrl_kmode_init() runs from resctrl_init() once the default group > > resctrl_kmode_init() can be dropped after changes described in response > to previous patch. Apart from no longer being necessary I also find that > having the kernel mode fully initialized *before* the hotplug handlers run > to be simpler. That means resctrl_set_kmode_support() will be called from the architecture layer, likely from core.c within get_rdt_alloc_resources(). The resctrl_set_kmode_support() handler would need to initialize both the default mode and all supported modes. I see that this is where the hotplug handler gets registered. Therefore, the modes are already initialized before the hotplug handler is set up. > >> has been set up. No user-visible behaviour changes yet; later patches > > (drop "later patches ...") > Sure. Thanks Babi