Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / mm / quicklist.c

diff --git a/kernel/mm/quicklist.c b/kernel/mm/quicklist.c
new file mode 100644 (file)
index 0000000..9422129
--- /dev/null
+++ b/kernel/mm/quicklist.c
@@ -0,0 +1,102 @@
+/*
+ * 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/gfp.h>
+#include <linux/mm.h>
+#include <linux/mmzone.h>
+#include <linux/quicklist.h>
+
+DEFINE_PER_CPU(struct quicklist [CONFIG_NR_QUICK], quicklist);
+
+#define FRACTION_OF_NODE_MEM   16
+
+static unsigned long max_pages(unsigned long min_pages)
+{
+       unsigned long node_free_pages, max;
+       int node = numa_node_id();
+       struct zone *zones = NODE_DATA(node)->node_zones;
+       int num_cpus_on_node;
+
+       node_free_pages =
+#ifdef CONFIG_ZONE_DMA
+               zone_page_state(&zones[ZONE_DMA], NR_FREE_PAGES) +
+#endif
+#ifdef CONFIG_ZONE_DMA32
+               zone_page_state(&zones[ZONE_DMA32], NR_FREE_PAGES) +
+#endif
+               zone_page_state(&zones[ZONE_NORMAL], NR_FREE_PAGES);
+
+       max = node_free_pages / FRACTION_OF_NODE_MEM;
+
+       num_cpus_on_node = cpumask_weight(cpumask_of_node(node));
+       max /= num_cpus_on_node;
+
+       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;
+}
+