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kernel add
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#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 <clameter@sgi.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 */
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