Merge branch 'upstream'

[sfrench/cifs-2.6.git] / include / linux / file.h

diff --git a/include/linux/file.h b/include/linux/file.h
index 9901b850f2e466158556711303829d6d114686ce..9f7c2513866f4d1a857398711f09864239b7162c 100644 (file)
--- a/include/linux/file.h
+++ b/include/linux/file.h
@@ -10,6 +10,7 @@
 #include <linux/compiler.h>
 #include <linux/spinlock.h>
 #include <linux/rcupdate.h>
+#include <linux/types.h>
 
 /*
  * The default fd array needs to be at least BITS_PER_LONG,
@@ -17,10 +18,22 @@
  */
 #define NR_OPEN_DEFAULT BITS_PER_LONG
 
+/*
+ * The embedded_fd_set is a small fd_set,
+ * suitable for most tasks (which open <= BITS_PER_LONG files)
+ */
+struct embedded_fd_set {
+       unsigned long fds_bits[1];
+};
+
+/*
+ * More than this number of fds: we use a separately allocated fd_set
+ */
+#define EMBEDDED_FD_SET_SIZE (BITS_PER_BYTE * sizeof(struct embedded_fd_set))
+
 struct fdtable {
        unsigned int max_fds;
        int max_fdset;
-       int next_fd;
        struct file ** fd;      /* current fd array */
        fd_set *close_on_exec;
        fd_set *open_fds;
@@ -33,13 +46,20 @@ struct fdtable {
  * Open file table structure
  */
 struct files_struct {
+  /*
+   * read mostly part
+   */
        atomic_t count;
        struct fdtable *fdt;
        struct fdtable fdtab;
-       fd_set close_on_exec_init;
-       fd_set open_fds_init;
+  /*
+   * written part on a separate cache line in SMP
+   */
+       spinlock_t file_lock ____cacheline_aligned_in_smp;
+       int next_fd;
+       struct embedded_fd_set close_on_exec_init;
+       struct embedded_fd_set open_fds_init;
        struct file * fd_array[NR_OPEN_DEFAULT];
-       spinlock_t file_lock;     /* Protects concurrent writers.  Nests inside tsk->alloc_lock */
 };
 
 #define files_fdtable(files) (rcu_dereference((files)->fdt))