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-rw-r--r--include/linux/quicklist.h93
1 files changed, 93 insertions, 0 deletions
diff --git a/include/linux/quicklist.h b/include/linux/quicklist.h
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+++ b/include/linux/quicklist.h
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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 */
+