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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/linux/percpu.h
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'include/linux/percpu.h')
-rw-r--r--include/linux/percpu.h61
1 files changed, 61 insertions, 0 deletions
diff --git a/include/linux/percpu.h b/include/linux/percpu.h
new file mode 100644
index 00000000000..5451eb1e781
--- /dev/null
+++ b/include/linux/percpu.h
@@ -0,0 +1,61 @@
+#ifndef __LINUX_PERCPU_H
+#define __LINUX_PERCPU_H
+#include <linux/spinlock.h> /* For preempt_disable() */
+#include <linux/slab.h> /* For kmalloc() */
+#include <linux/smp.h>
+#include <linux/string.h> /* For memset() */
+#include <asm/percpu.h>
+
+/* Enough to cover all DEFINE_PER_CPUs in kernel, including modules. */
+#ifndef PERCPU_ENOUGH_ROOM
+#define PERCPU_ENOUGH_ROOM 32768
+#endif
+
+/* Must be an lvalue. */
+#define get_cpu_var(var) (*({ preempt_disable(); &__get_cpu_var(var); }))
+#define put_cpu_var(var) preempt_enable()
+
+#ifdef CONFIG_SMP
+
+struct percpu_data {
+ void *ptrs[NR_CPUS];
+ void *blkp;
+};
+
+/*
+ * Use this to get to a cpu's version of the per-cpu object allocated using
+ * alloc_percpu. Non-atomic access to the current CPU's version should
+ * probably be combined with get_cpu()/put_cpu().
+ */
+#define per_cpu_ptr(ptr, cpu) \
+({ \
+ struct percpu_data *__p = (struct percpu_data *)~(unsigned long)(ptr); \
+ (__typeof__(ptr))__p->ptrs[(cpu)]; \
+})
+
+extern void *__alloc_percpu(size_t size, size_t align);
+extern void free_percpu(const void *);
+
+#else /* CONFIG_SMP */
+
+#define per_cpu_ptr(ptr, cpu) (ptr)
+
+static inline void *__alloc_percpu(size_t size, size_t align)
+{
+ void *ret = kmalloc(size, GFP_KERNEL);
+ if (ret)
+ memset(ret, 0, size);
+ return ret;
+}
+static inline void free_percpu(const void *ptr)
+{
+ kfree(ptr);
+}
+
+#endif /* CONFIG_SMP */
+
+/* Simple wrapper for the common case: zeros memory. */
+#define alloc_percpu(type) \
+ ((type *)(__alloc_percpu(sizeof(type), __alignof__(type))))
+
+#endif /* __LINUX_PERCPU_H */