X-Git-Url: https://repo.jachan.dev/linux.git/blobdiff_plain/3b621ee5df437d3f332a635ab6421aaa61a7dc2b..db1a19b38f3a85f475b4ad716c71be133d8ca48e:/include/linux/file.h

diff --git a/include/linux/file.h b/include/linux/file.h
index d3b1a15d5f21..74183e6f7f45 100644
--- 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 {
-        atomic_t count;
-        spinlock_t file_lock;     /* Protects all the below members.  Nests inside tsk->alloc_lock */
+  /*
+   * read mostly part
+   */
+	atomic_t count;
 	struct fdtable *fdt;
 	struct fdtable fdtab;
-        fd_set close_on_exec_init;
-        fd_set open_fds_init;
-        struct file * fd_array[NR_OPEN_DEFAULT];
+  /*
+   * 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];
 };
 
 #define files_fdtable(files) (rcu_dereference((files)->fdt))
@@ -60,8 +80,6 @@ extern void put_filp(struct file *);
 extern int get_unused_fd(void);
 extern void FASTCALL(put_unused_fd(unsigned int fd));
 struct kmem_cache;
-extern void filp_ctor(void * objp, struct kmem_cache *cachep, unsigned long cflags);
-extern void filp_dtor(void * objp, struct kmem_cache *cachep, unsigned long dflags);
 
 extern struct file ** alloc_fd_array(int);
 extern void free_fd_array(struct file **, int);
@@ -94,5 +112,6 @@ struct task_struct;
 
 struct files_struct *get_files_struct(struct task_struct *);
 void FASTCALL(put_files_struct(struct files_struct *fs));
+void reset_files_struct(struct task_struct *, struct files_struct *);
 
 #endif /* __LINUX_FILE_H */