Hi, "Peter Teoh" <htmldeveloper@xxxxxxxxx> writes: > Hi Thomas Petazzoni, > > On Fri, Mar 14, 2008 at 10:06 PM, Peter Teoh <htmldeveloper@xxxxxxxxx> wrote: >> > >> > The tag __initdata is for data used only during initialization (the >> > data is put in a special ELF section that is discarded after >> > initialization). >> > >> > >> >> When is the discarding taking place? Which part of the kernel source >> code is doing the discarding? >> > Just would like ask again does anyone know when is the memory > discarding (of the ELF section marked as __initdata) taking place? > > first, the memory freeing must be triggered only after the __initdata > functions have been executed - how does the kernel knows that? next, > this memory freeing MAY be executed while the module is still loaded - > so someone has to trigger the operation some where. when and where > -> within the kernel source code -- are these found? __initdata functions? As far as I understood it, for modules, it works like this: When a module is requested to load, the loader parses the ELF file and allocates memory for the sections and saves pointers to them in a struct module, including the init section of the module ELF. Then all init-stuff is and mapped into this executable vmalloc-region. After ->init() has run (defined by module_init()), ->module_init is freed again. You can see this happen in sys_init_module(). On the other hand, the core kernel init stuff (on x86) is freed in free_initmem(), called by init_post(), called at the end of kernel_init() when all __init functions are done. Hannes -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to ecartis@xxxxxxxxxxxx Please read the FAQ at http://kernelnewbies.org/FAQ
