On Fri, Oct 24 2025, Mike Rapoport wrote: > On Wed, Oct 22, 2025 at 01:01:08PM +0200, Pratyush Yadav wrote: >> Hi Pasha, >> >> On Tue, Oct 21 2025, Pasha Tatashin wrote: >> >> > From: "Mike Rapoport (Microsoft)" <[email protected]> >> > >> > The KHO framework uses a notifier chain as the mechanism for clients to >> > participate in the finalization process. While this works for a single, >> > central state machine, it is too restrictive for kernel-internal >> > components like pstore/reserve_mem or IMA. These components need a >> > simpler, direct way to register their state for preservation (e.g., >> > during their initcall) without being part of a complex, >> > shutdown-time notifier sequence. The notifier model forces all >> > participants into a single finalization flow and makes direct >> > preservation from an arbitrary context difficult. >> > This patch refactors the client participation model by removing the >> > notifier chain and introducing a direct API for managing FDT subtrees. >> > >> > The core kho_finalize() and kho_abort() state machine remains, but >> > clients now register their data with KHO beforehand. >> > > > ... > >> > @@ -1280,7 +1298,7 @@ static __init int kho_init(void) >> > kho_enable = false; >> > return err; >> > } >> > -late_initcall(kho_init); >> > +fs_initcall(kho_init); >> >> Is this change related to this patch? Also, why fs_initcall? > > memblock registers sub-fdt in late_initcall(), so we should have the root > fdt ready by then.
I see. Should this be even earlier then? Other components might also depend on KHO being initialized, and those might be at or before fs_initcall. For example, LUO does its init using early_initcall and uses KHO, even before it is initialized [0]. This works because kho_retrieve_subtree() only uses parts initialized very early in boot (the KHO FDT), but I suppose we want to have a proper initialization order to not rely on things that just happen to work until they don't. Since kho_init() has a dependency on debugfs, which gets initialized in core_initcall, I guess the earliest it can be is postcore_initcall. Or, we split out the debugfs parts into a separate init function (they have their own file anyway) and initialize "core KHO" in early_initcall? Then LUO can be in core_initcall and all its users in later ones. Thoughts? [0] https://lore.kernel.org/lkml/[email protected]/ -- Regards, Pratyush Yadav
