Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / include / linux / percpu_ida.h

diff --git a/kernel/include/linux/percpu_ida.h b/kernel/include/linux/percpu_ida.h
new file mode 100644 (file)
index 0000000..f5cfdd6
--- /dev/null
+++ b/kernel/include/linux/percpu_ida.h
@@ -0,0 +1,82 @@
+#ifndef __PERCPU_IDA_H__
+#define __PERCPU_IDA_H__
+
+#include <linux/types.h>
+#include <linux/bitops.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/spinlock_types.h>
+#include <linux/wait.h>
+#include <linux/cpumask.h>
+
+struct percpu_ida_cpu;
+
+struct percpu_ida {
+       /*
+        * number of tags available to be allocated, as passed to
+        * percpu_ida_init()
+        */
+       unsigned                        nr_tags;
+       unsigned                        percpu_max_size;
+       unsigned                        percpu_batch_size;
+
+       struct percpu_ida_cpu __percpu  *tag_cpu;
+
+       /*
+        * Bitmap of cpus that (may) have tags on their percpu freelists:
+        * steal_tags() uses this to decide when to steal tags, and which cpus
+        * to try stealing from.
+        *
+        * It's ok for a freelist to be empty when its bit is set - steal_tags()
+        * will just keep looking - but the bitmap _must_ be set whenever a
+        * percpu freelist does have tags.
+        */
+       cpumask_t                       cpus_have_tags;
+
+       struct {
+               spinlock_t              lock;
+               /*
+                * When we go to steal tags from another cpu (see steal_tags()),
+                * we want to pick a cpu at random. Cycling through them every
+                * time we steal is a bit easier and more or less equivalent:
+                */
+               unsigned                cpu_last_stolen;
+
+               /* For sleeping on allocation failure */
+               wait_queue_head_t       wait;
+
+               /*
+                * Global freelist - it's a stack where nr_free points to the
+                * top
+                */
+               unsigned                nr_free;
+               unsigned                *freelist;
+       } ____cacheline_aligned_in_smp;
+};
+
+/*
+ * Number of tags we move between the percpu freelist and the global freelist at
+ * a time
+ */
+#define IDA_DEFAULT_PCPU_BATCH_MOVE    32U
+/* Max size of percpu freelist, */
+#define IDA_DEFAULT_PCPU_SIZE  ((IDA_DEFAULT_PCPU_BATCH_MOVE * 3) / 2)
+
+int percpu_ida_alloc(struct percpu_ida *pool, int state);
+void percpu_ida_free(struct percpu_ida *pool, unsigned tag);
+
+void percpu_ida_destroy(struct percpu_ida *pool);
+int __percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags,
+       unsigned long max_size, unsigned long batch_size);
+static inline int percpu_ida_init(struct percpu_ida *pool, unsigned long nr_tags)
+{
+       return __percpu_ida_init(pool, nr_tags, IDA_DEFAULT_PCPU_SIZE,
+               IDA_DEFAULT_PCPU_BATCH_MOVE);
+}
+
+typedef int (*percpu_ida_cb)(unsigned, void *);
+int percpu_ida_for_each_free(struct percpu_ida *pool, percpu_ida_cb fn,
+       void *data);
+
+unsigned percpu_ida_free_tags(struct percpu_ida *pool, int cpu);
+#endif /* __PERCPU_IDA_H__ */