Re: [PATCH 03/10] mm: make hugetlb.c explicitly non-modular

From: Mike Kravetz
Date: Wed Aug 26 2015 - 12:47:34 EST


On 08/24/2015 03:14 PM, Paul Gortmaker wrote:
> The Kconfig currently controlling compilation of this code is:
>
> config HUGETLBFS
> bool "HugeTLB file system support"
>
> ...meaning that it currently is not being built as a module by anyone.
>
> Lets remove the modular code that is essentially orphaned, so that
> when reading the file there is no doubt it is builtin-only.
>
> Since module_init translates to device_initcall in the non-modular
> case, the init ordering remains unchanged with this commit. However
> one could argue that fs_initcall() would make more sense here.

I would prefer that it NOT be changed to fs_initcall() as this is more
about generic mm code than fs code. If this was in a hugetlbfs specific
file, fs_initcall() might make more sense.

More about changing initcall below.

> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
> Cc: David Rientjes <rientjes@xxxxxxxxxx>
> Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
> Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
> Cc: linux-mm@xxxxxxxxx
> Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
> ---
> mm/hugetlb.c | 39 +--------------------------------------
> 1 file changed, 1 insertion(+), 38 deletions(-)
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 586aa69df900..1154152c8b99 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -4,7 +4,6 @@
> */
> #include <linux/list.h>
> #include <linux/init.h>
> -#include <linux/module.h>
> #include <linux/mm.h>
> #include <linux/seq_file.h>
> #include <linux/sysctl.h>
> @@ -2439,25 +2438,6 @@ static void hugetlb_unregister_node(struct node *node)
> nhs->hugepages_kobj = NULL;
> }
>
> -/*
> - * hugetlb module exit: unregister hstate attributes from node devices
> - * that have them.
> - */
> -static void hugetlb_unregister_all_nodes(void)
> -{
> - int nid;
> -
> - /*
> - * disable node device registrations.
> - */
> - register_hugetlbfs_with_node(NULL, NULL);
> -
> - /*
> - * remove hstate attributes from any nodes that have them.
> - */
> - for (nid = 0; nid < nr_node_ids; nid++)
> - hugetlb_unregister_node(node_devices[nid]);
> -}
>
> /*
> * Register hstate attributes for a single node device.
> @@ -2522,27 +2502,10 @@ static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp)
> return NULL;
> }
>
> -static void hugetlb_unregister_all_nodes(void) { }
> -
> static void hugetlb_register_all_nodes(void) { }
>
> #endif
>
> -static void __exit hugetlb_exit(void)
> -{
> - struct hstate *h;
> -
> - hugetlb_unregister_all_nodes();
> -
> - for_each_hstate(h) {
> - kobject_put(hstate_kobjs[hstate_index(h)]);
> - }
> -
> - kobject_put(hugepages_kobj);
> - kfree(hugetlb_fault_mutex_table);
> -}
> -module_exit(hugetlb_exit);
> -
> static int __init hugetlb_init(void)
> {
> int i;
> @@ -2580,7 +2543,7 @@ static int __init hugetlb_init(void)
> mutex_init(&hugetlb_fault_mutex_table[i]);
> return 0;
> }

I am all for removal of the module_exit and associated code. It is
dead and is not used today. It would be a good idea to remove this
in any case.

> -module_init(hugetlb_init);
> +device_initcall(hugetlb_init);

Other more experienced people have opinions on your staged approach
to changing these init calls. If the consensus is to take this
approach, I would have no objections.

--
Mike Kravetz

>
> /* Should be called on processing a hugepagesz=... option */
> void __init hugetlb_add_hstate(unsigned order)
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/