On Tue, Feb 18, 2025 at 05:42:57PM +0900, Masami Hiramatsu wrote: > Hi Mike, > > On Tue, 18 Feb 2025 09:24:53 +0200 > Mike Rapoport <[email protected]> wrote: > > > Hi Masami, > > > > On Tue, Feb 11, 2025 at 11:47:03PM +0900, Masami Hiramatsu (Google) wrote: > > > From: Masami Hiramatsu (Google) <[email protected]> > > > > > > Add reserve_mem_release_by_name() to release a reserved memory region > > > with a given name. This allows us to release reserved memory which is > > > defined by kernel cmdline, after boot. > > > > > > Signed-off-by: Masami Hiramatsu (Google) <[email protected]> > > > Cc: Andrew Morton <[email protected]> > > > Cc: Mike Rapoport <[email protected]> > > > Cc: [email protected] > > > > ... > > > > > +/** > > > + * reserve_mem_release_by_name - Release reserved memory region with a > > > given name > > > + * @name: The name that is attatched to a reserved memory region > > > + * > > > + * Forcibly release the pages in the reserved memory region so that > > > those memory > > > + * can be used as free memory. After released the reserved region size > > > becomes 0. > > > + * > > > + * Returns: 1 if released or 0 if not found. > > > + */ > > > +int reserve_mem_release_by_name(const char *name) > > > +{ > > > + struct reserve_mem_table *map; > > > + unsigned int page_count; > > > + phys_addr_t start; > > > + > > > + guard(mutex)(&reserve_mem_lock); > > > + map = reserve_mem_find_by_name_nolock(name); > > > + if (!map) > > > + return 0; > > > + > > > + start = map->start; > > > + page_count = DIV_ROUND_UP(map->size, PAGE_SIZE); > > > + > > > + for (int i = 0; i < page_count; i++) { > > > + phys_addr_t addr = start + i * PAGE_SIZE; > > > + struct page *page = pfn_to_page(addr >> PAGE_SHIFT); > > > + > > > + page->flags &= ~BIT(PG_reserved); > > > + __free_page(page); > > > + } > > > > We have free_reserved_area(), please use it here. > > Otherwise > > > > Acked-by: Mike Rapoport (Microsoft) <[email protected]> > > Thanks! but I can not use free_reserved_area() here because it uses > virt_to_page(). Here we only know the physical address in the map. > I think we can use free_reserved_page() instead. Is that OK?
For reserve_mem ranges virt_to_phys() will work, they are allocated from the memory that is covered by the direct map. > Thank you, > > -- > Masami Hiramatsu (Google) <[email protected]> -- Sincerely yours, Mike.
