Re: [PATCH v2] page_ext: introduce boot parameter 'early_page_ext'

[Michal Hocko <mhocko@suse.com>]

On Thu 25-08-22 14:21:29, lizhe.67@bytedance.com wrote:
> On 2022-08-24 8:09 UTC, mhocko@suse.com wrote:
[...]
> >> diff --git a/init/main.c b/init/main.c
> >> index 91642a4e69be..3760c0326525 100644
> >> --- a/init/main.c
> >> +++ b/init/main.c
> >> @@ -849,6 +849,8 @@ static void __init mm_init(void)
> >>  	pgtable_init();
> >>  	debug_objects_mem_init();
> >>  	vmalloc_init();
> >> +	/* Should be run after vmap initialization */
> >> +	page_ext_init(true);
> >
> >you can just 
> >	if (early_page_ext)
> >		page_ext_init();
> >
> >>  	/* Should be run before the first non-init thread is created */
> >>  	init_espfix_bsp();
> >>  	/* Should be run after espfix64 is set up. */
> >> @@ -1606,7 +1608,7 @@ static noinline void __init kernel_init_freeable(void)
> >>  	padata_init();
> >>  	page_alloc_init_late();
> >>  	/* Initialize page ext after all struct pages are initialized. */
> >> -	page_ext_init();
> >> +	page_ext_init(false);
> >
> >	if (!early_page_ext)
> >		page_ext_init();
> 
> I think we can use an inline function instead of 'early_page_ext' here. The
> reason is that if CONFIG_PAGE_EXTENSION=n, 'early_page_ext' is undefined.
> Thought we can #define early_page_ext as false, it is ugly.

Agreed!

-- 
Michal Hocko
SUSE Labs