[mirror_ubuntu-zesty-kernel.git] / include / linux / quicklist.h

#ifndef LINUX_QUICKLIST_H
#define LINUX_QUICKLIST_H
/*
 * Fast allocations and disposal of pages. Pages must be in the condition
 * as needed after allocation when they are freed. Per cpu lists of pages
 * are kept that only contain node local pages.
 *
 * (C) 2007, SGI. Christoph Lameter <cl@linux.com>
 */
#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/percpu.h>

#ifdef CONFIG_QUICKLIST

struct quicklist {
	void *page;
	int nr_pages;
};

DECLARE_PER_CPU(struct quicklist, quicklist)[CONFIG_NR_QUICK];

/*
 * The two key functions quicklist_alloc and quicklist_free are inline so
 * that they may be custom compiled for the platform.
 * Specifying a NULL ctor can remove constructor support. Specifying
 * a constant quicklist allows the determination of the exact address
 * in the per cpu area.
 *
 * The fast patch in quicklist_alloc touched only a per cpu cacheline and
 * the first cacheline of the page itself. There is minmal overhead involved.
 */
static inline void *quicklist_alloc(int nr, gfp_t flags, void (*ctor)(void *))
{
	struct quicklist *q;
	void **p = NULL;

	q =&get_cpu_var(quicklist)[nr];
	p = q->page;
	if (likely(p)) {
		q->page = p[0];
		p[0] = NULL;
		q->nr_pages--;
	}
	put_cpu_var(quicklist);
	if (likely(p))
		return p;

	p = (void *)__get_free_page(flags | __GFP_ZERO);
	if (ctor && p)
		ctor(p);
	return p;
}

static inline void __quicklist_free(int nr, void (*dtor)(void *), void *p,
	struct page *page)
{
	struct quicklist *q;

	q = &get_cpu_var(quicklist)[nr];
	*(void **)p = q->page;
	q->page = p;
	q->nr_pages++;
	put_cpu_var(quicklist);
}

static inline void quicklist_free(int nr, void (*dtor)(void *), void *pp)
{
	__quicklist_free(nr, dtor, pp, virt_to_page(pp));
}

static inline void quicklist_free_page(int nr, void (*dtor)(void *),
							struct page *page)
{
	__quicklist_free(nr, dtor, page_address(page), page);
}

void quicklist_trim(int nr, void (*dtor)(void *),
	unsigned long min_pages, unsigned long max_free);

unsigned long quicklist_total_size(void);

#else

static inline unsigned long quicklist_total_size(void)
{
	return 0;
}

#endif

#endif /* LINUX_QUICKLIST_H */
Commit	Line	Data
6225e937 CL	1	#ifndef LINUX_QUICKLIST_H
	2	#define LINUX_QUICKLIST_H
	3	/*
	4	* Fast allocations and disposal of pages. Pages must be in the condition
	5	* as needed after allocation when they are freed. Per cpu lists of pages
	6	* are kept that only contain node local pages.
	7	*
93e205a7	8	* (C) 2007, SGI. Christoph Lameter <cl@linux.com>
6225e937 CL	9	*/
	10	#include <linux/kernel.h>
	11	#include <linux/gfp.h>
	12	#include <linux/percpu.h>
	13
	14	#ifdef CONFIG_QUICKLIST
	15
	16	struct quicklist {
	17	void *page;
	18	int nr_pages;
	19	};
	20
	21	DECLARE_PER_CPU(struct quicklist, quicklist)[CONFIG_NR_QUICK];
	22
	23	/*
	24	* The two key functions quicklist_alloc and quicklist_free are inline so
	25	* that they may be custom compiled for the platform.
	26	* Specifying a NULL ctor can remove constructor support. Specifying
	27	* a constant quicklist allows the determination of the exact address
	28	* in the per cpu area.
	29	*
	30	* The fast patch in quicklist_alloc touched only a per cpu cacheline and
	31	* the first cacheline of the page itself. There is minmal overhead involved.
	32	*/
	33	static inline void quicklist_alloc(int nr, gfp_t flags, void (ctor)(void *))
	34	{
	35	struct quicklist *q;
	36	void **p = NULL;
	37
	38	q =&get_cpu_var(quicklist)[nr];
	39	p = q->page;
	40	if (likely(p)) {
	41	q->page = p[0];
	42	p[0] = NULL;
	43	q->nr_pages--;
	44	}
	45	put_cpu_var(quicklist);
	46	if (likely(p))
	47	return p;
	48
	49	p = (void *)__get_free_page(flags \| __GFP_ZERO);
	50	if (ctor && p)
	51	ctor(p);
	52	return p;
	53	}
	54
	55	static inline void __quicklist_free(int nr, void (dtor)(void ), void *p,
	56	struct page *page)
	57	{
	58	struct quicklist *q;
6225e937 CL	59
	60	q = &get_cpu_var(quicklist)[nr];
	61	(void *)p = q->page;
	62	q->page = p;
	63	q->nr_pages++;
	64	put_cpu_var(quicklist);
	65	}
	66
	67	static inline void quicklist_free(int nr, void (dtor)(void ), void *pp)
	68	{
	69	__quicklist_free(nr, dtor, pp, virt_to_page(pp));
	70	}
	71
	72	static inline void quicklist_free_page(int nr, void (dtor)(void ),
	73	struct page *page)
	74	{
	75	__quicklist_free(nr, dtor, page_address(page), page);
	76	}
	77
	78	void quicklist_trim(int nr, void (dtor)(void ),
	79	unsigned long min_pages, unsigned long max_free);
	80
	81	unsigned long quicklist_total_size(void);
	82
4b856152 KM	83	#else
	84
	85	static inline unsigned long quicklist_total_size(void)
	86	{
	87	return 0;
	88	}
	89
6225e937 CL	90	#endif
	91
	92	#endif /* LINUX_QUICKLIST_H */
	93