4 files changed, 189 insertions, 0 deletions

diff --git a/include/linux/quicklist.h b/include/linux/quicklist.h
new file mode 100644
index 000000000000..9371c6116df3
--- /dev/null
+++ b/include/linux/quicklist.h
@@ -0,0 +1,94 @@
+#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;
+        int nid = page_to_nid(page);
+
+        if (unlikely(nid != numa_node_id())) {
+                if (dtor)
+                        dtor(p);
+                __free_page(page);
+                return;
+        }
+
+        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);
+
+#endif
+
+#endif /* LINUX_QUICKLIST_H */
+
diff --git a/mm/Kconfig b/mm/Kconfig
index 7942b333e46c..1ac718f636ec 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -163,3 +163,8 @@ config ZONE_DMA_FLAG
         default "0" if !ZONE_DMA
         default "1"
 
+config NR_QUICK
+        int
+        depends on QUICKLIST
+        default "1"
+
diff --git a/mm/Makefile b/mm/Makefile
index 1887148e44e7..a9148ea329aa 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -30,3 +30,5 @@ obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
 obj-$(CONFIG_FS_XIP) += filemap_xip.o
 obj-$(CONFIG_MIGRATION) += migrate.o
 obj-$(CONFIG_SMP) += allocpercpu.o
+obj-$(CONFIG_QUICKLIST) += quicklist.o
+
diff --git a/mm/quicklist.c b/mm/quicklist.c
new file mode 100644
index 000000000000..ae8189c2799e
--- /dev/null
+++ b/mm/quicklist.c
@@ -0,0 +1,88 @@
+/*
+ * Quicklist support.
+ *
+ * Quicklists are light weight lists of pages that have a defined state
+ * on alloc and free. Pages must be in the quicklist specific defined state
+ * (zero by default) when the page is freed. It seems that the initial idea
+ * for such lists first came from Dave Miller and then various other people
+ * improved on it.
+ *
+ * Copyright (C) 2007 SGI,
+ *      Christoph Lameter <clameter@sgi.com>
+ *              Generalized, added support for multiple lists and
+ *              constructors / destructors.
+ */
+#include <linux/kernel.h>
+
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/module.h>
+#include <linux/quicklist.h>
+
+DEFINE_PER_CPU(struct quicklist, quicklist)[CONFIG_NR_QUICK];
+
+#define FRACTION_OF_NODE_MEM    16
+
+static unsigned long max_pages(unsigned long min_pages)
+{
+        unsigned long node_free_pages, max;
+
+        node_free_pages = node_page_state(numa_node_id(),
+                        NR_FREE_PAGES);
+        max = node_free_pages / FRACTION_OF_NODE_MEM;
+        return max(max, min_pages);
+}
+
+static long min_pages_to_free(struct quicklist *q,
+        unsigned long min_pages, long max_free)
+{
+        long pages_to_free;
+
+        pages_to_free = q->nr_pages - max_pages(min_pages);
+
+        return min(pages_to_free, max_free);
+}
+
+/*
+ * Trim down the number of pages in the quicklist
+ */
+void quicklist_trim(int nr, void (*dtor)(void *),
+        unsigned long min_pages, unsigned long max_free)
+{
+        long pages_to_free;
+        struct quicklist *q;
+
+        q = &get_cpu_var(quicklist)[nr];
+        if (q->nr_pages > min_pages) {
+                pages_to_free = min_pages_to_free(q, min_pages, max_free);
+
+                while (pages_to_free > 0) {
+                        /*
+                         * We pass a gfp_t of 0 to quicklist_alloc here
+                         * because we will never call into the page allocator.
+                         */
+                        void *p = quicklist_alloc(nr, 0, NULL);
+
+                        if (dtor)
+                                dtor(p);
+                        free_page((unsigned long)p);
+                        pages_to_free--;
+                }
+        }
+        put_cpu_var(quicklist);
+}
+
+unsigned long quicklist_total_size(void)
+{
+        unsigned long count = 0;
+        int cpu;
+        struct quicklist *ql, *q;
+
+        for_each_online_cpu(cpu) {
+                ql = per_cpu(quicklist, cpu);
+                for (q = ql; q < ql + CONFIG_NR_QUICK; q++)
+                        count += q->nr_pages;
+        }
+        return count;
+}
+