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Commit 2c85f51d authored by Jan Beulich's avatar Jan Beulich Committed by Linus Torvalds
Browse files

mm: also use alloc_large_system_hash() for the PID hash table 



This is being done by allowing boot time allocations to specify that they
may want a sub-page sized amount of memory.

Overall this seems more consistent with the other hash table allocations,
and allows making two supposedly mm-only variables really mm-only
(nr_{kernel,all}_pages).

Signed-off-by: default avatarJan Beulich <jbeulich@novell.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3c1596ef

include/linux/bootmem.h

+2 −3
Original line number Diff line number Diff line
@@ -132,9 +132,6 @@ static inline void *alloc_remap(int nid, unsigned long size) 
}

#endif /* CONFIG_HAVE_ARCH_ALLOC_REMAP */



extern unsigned long __meminitdata nr_kernel_pages;

extern unsigned long __meminitdata nr_all_pages;



extern void *alloc_large_system_hash(const char *tablename,

				     unsigned long bucketsize,

				     unsigned long numentries,
@@ -145,6 +142,8 @@ extern void *alloc_large_system_hash(const char *tablename, 
				     unsigned long limit);



#define HASH_EARLY	0x00000001	/* Allocating during early boot? */

#define HASH_SMALL	0x00000002	/* sub-page allocation allowed, min

					 * shift passed via *_hash_shift */



/* Only NUMA needs hash distribution. 64bit NUMA architectures have

 * sufficient vmalloc space.

kernel/pid.c

+4 −11
Original line number Diff line number Diff line
@@ -40,7 +40,7 @@ 
#define pid_hashfn(nr, ns)	\

	hash_long((unsigned long)nr + (unsigned long)ns, pidhash_shift)

static struct hlist_head *pid_hash;

static int pidhash_shift;

static unsigned int pidhash_shift = 4;

struct pid init_struct_pid = INIT_STRUCT_PID;



int pid_max = PID_MAX_DEFAULT;
@@ -499,19 +499,12 @@ struct pid *find_ge_pid(int nr, struct pid_namespace *ns) 
void __init pidhash_init(void)

{

	int i, pidhash_size;

	unsigned long megabytes = nr_kernel_pages >> (20 - PAGE_SHIFT);



	pidhash_shift = max(4, fls(megabytes * 4));

	pidhash_shift = min(12, pidhash_shift);

	pid_hash = alloc_large_system_hash("PID", sizeof(*pid_hash), 0, 18,

					   HASH_EARLY | HASH_SMALL,

					   &pidhash_shift, NULL, 4096);

	pidhash_size = 1 << pidhash_shift;



	printk("PID hash table entries: %d (order: %d, %Zd bytes)\n",

		pidhash_size, pidhash_shift,

		pidhash_size * sizeof(struct hlist_head));



	pid_hash = alloc_bootmem(pidhash_size *	sizeof(*(pid_hash)));

	if (!pid_hash)

		panic("Could not alloc pidhash!\n");

	for (i = 0; i < pidhash_size; i++)

		INIT_HLIST_HEAD(&pid_hash[i]);

}

mm/page_alloc.c

+10 −3
Original line number Diff line number Diff line
@@ -124,8 +124,8 @@ static char * const zone_names[MAX_NR_ZONES] = { 


int min_free_kbytes = 1024;



unsigned long __meminitdata nr_kernel_pages;

unsigned long __meminitdata nr_all_pages;

static unsigned long __meminitdata nr_kernel_pages;

static unsigned long __meminitdata nr_all_pages;

static unsigned long __meminitdata dma_reserve;



#ifdef CONFIG_ARCH_POPULATES_NODE_MAP
@@ -4821,7 +4821,14 @@ void *__init alloc_large_system_hash(const char *tablename, 
			numentries <<= (PAGE_SHIFT - scale);



		/* Make sure we've got at least a 0-order allocation.. */

		if (unlikely((numentries * bucketsize) < PAGE_SIZE))

		if (unlikely(flags & HASH_SMALL)) {

			/* Makes no sense without HASH_EARLY */

			WARN_ON(!(flags & HASH_EARLY));

			if (!(numentries >> *_hash_shift)) {

				numentries = 1UL << *_hash_shift;

				BUG_ON(!numentries);

			}

		} else if (unlikely((numentries * bucketsize) < PAGE_SIZE))

			numentries = PAGE_SIZE / bucketsize;

	}

	numentries = roundup_pow_of_two(numentries);