Revert "hugetlb: Add hugetlb_dynamic_pool sysctl"

This reverts commit 54f9f80d6543fb7b157d3b11e2e7911dc1379790 ("hugetlb:
Add hugetlb_dynamic_pool sysctl")

Given the new sysctl nr_overcommit_hugepages, the boolean dynamic pool
sysctl is not needed, as its semantics can be expressed by 0 in the
overcommit sysctl (no dynamic pool) and non-0 in the overcommit sysctl
(pool enabled).

(Needed in 2.6.24 since it reverts a post-2.6.23 userspace-visible change)

Signed-off-by: Nishanth Aravamudan <[e-mail]>
Acked-by: Adam Litke <[e-mail]>
Cc: William Lee Irwin III <[e-mail]>
Cc: Dave Hansen <[e-mail]>
Cc: David Gibson <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

include/linux/hugetlb.h

···
 
 extern unsigned long max_huge_pages;
 extern unsigned long hugepages_treat_as_movable;
-extern int hugetlb_dynamic_pool;
 extern unsigned long nr_overcommit_huge_pages;
 extern const unsigned long hugetlb_zero, hugetlb_infinity;
 extern int sysctl_hugetlb_shm_group;

kernel/sysctl.c

···
 	},
 	{
 		.ctl_name	= CTL_UNNUMBERED,
-		.procname	= "hugetlb_dynamic_pool",
-		.data		= &hugetlb_dynamic_pool,
-		.maxlen		= sizeof(hugetlb_dynamic_pool),
-		.mode		= 0644,
-		.proc_handler	= &proc_dointvec,
-	},
-	{
-		.ctl_name	= CTL_UNNUMBERED,
 		.procname	= "nr_overcommit_hugepages",
 		.data		= &nr_overcommit_huge_pages,
 		.maxlen		= sizeof(nr_overcommit_huge_pages),

mm/hugetlb.c

···
 static unsigned int surplus_huge_pages_node[MAX_NUMNODES];
 static gfp_t htlb_alloc_mask = GFP_HIGHUSER;
 unsigned long hugepages_treat_as_movable;
-int hugetlb_dynamic_pool;
 unsigned long nr_overcommit_huge_pages;
 static int hugetlb_next_nid;
 
···
 {
 	struct page *page;
 	unsigned int nid;
-
-	/* Check if the dynamic pool is enabled */
-	if (!hugetlb_dynamic_pool)
-		return NULL;
 
 	/*
 	 * Assume we will successfully allocate the surplus page to