On Mon, Oct 14, 2024 at 1:37 PM Suren Baghdasaryan <[email protected]> wrote: > > Add CONFIG_PGALLOC_TAG_USE_PAGEFLAGS to store allocation tag > references directly in the page flags. This eliminates memory > overhead caused by page_ext and results in better performance > for page allocations. > If the number of available page flag bits is insufficient to > address all kernel allocations, profiling falls back to using > page extensions with an appropriate warning to disable this > config. > If dynamically loaded modules add enough tags that they can't > be addressed anymore with available page flag bits, memory > profiling gets disabled and a warning is issued.
Just curious, why do we need a config option? If there are enough bits in page flags, why not use them automatically or fallback to page_ext otherwise? Is the reason that dynamically loadable modules, where the user may know in advance that the page flags won't be enough with the modules loaded?
