1 files changed, 88 insertions, 0 deletions

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;
+}
+