On Wed, Jan 31, 2024 at 09:58:21AM -0500, Mathieu Desnoyers wrote: > On 2024-01-30 21:48, Dave Chinner wrote: > > On Tue, Jan 30, 2024 at 11:52:54AM -0500, Mathieu Desnoyers wrote: > > > Introduce a generic way to query whether the dcache is virtually aliased > > > on all architectures. Its purpose is to ensure that subsystems which > > > are incompatible with virtually aliased data caches (e.g. FS_DAX) can > > > reliably query this. > > > > > > For dcache aliasing, there are three scenarios dependending on the > > > architecture. Here is a breakdown based on my understanding: > > > > > > A) The dcache is always aliasing: > > > > > > * arc > > > * csky > > > * m68k (note: shared memory mappings are incoherent ? SHMLBA is missing there.) > > > * sh > > > * parisc > > > > /me wonders why the dentry cache aliasing has problems on these > > systems. > > > > Oh, dcache != fs/dcache.c (the VFS dentry cache). > > > > Can you please rename this function appropriately so us dumb > > filesystem people don't confuse cpu data cache configurations with > > the VFS dentry cache aliasing when we read this code? Something like > > cpu_dcache_is_aliased(), perhaps? > > Good point, will do. I'm planning go rename as follows for v3 to > eliminate confusion with dentry cache (and with "page cache" in > general): > > ARCH_HAS_CACHE_ALIASING -> ARCH_HAS_CPU_CACHE_ALIASING > dcache_is_aliasing() -> cpu_dcache_is_aliasing() > > I noticed that you suggested "aliased" rather than "aliasing", > but I followed what arm64 did for icache_is_aliasing(). Do you > have a strong preference one way or another ? Not really. -Dave. -- Dave Chinner david@xxxxxxxxxxxxx
