Merge pull request #311 from arafatms/tk4/0009-kabi-performance

Improve performance for unixbench test

drivers/android/binder.c

@@ -2232,10 +2232,12 @@ static void binder_deferred_fd_close(int fd)
 		return;
 	init_task_work(&twcb->twork, binder_do_fd_close);
 	__close_fd_get_file(fd, &twcb->file);
-	if (twcb->file)
+	if (twcb->file) {
+		filp_close(twcb->file, current->files);
 		task_work_add(current, &twcb->twork, true);
-	else
+	} else {
 		kfree(twcb);
+	}
 }
 
 static void binder_transaction_buffer_release(struct binder_proc *proc,

fs/file.c

@@ -642,7 +642,9 @@ out_unlock:
 EXPORT_SYMBOL(__close_fd); /* for ksys_close() */
 
 /*
- * variant of __close_fd that gets a ref on the file for later fput
+ * variant of __close_fd that gets a ref on the file for later fput.
+ * The caller must ensure that filp_close() called on the file, and then
+ * an fput().
  */
 int __close_fd_get_file(unsigned int fd, struct file **res)
 {
@@ -662,7 +664,7 @@ int __close_fd_get_file(unsigned int fd, struct file **res)
 	spin_unlock(&files->file_lock);
 	get_file(file);
 	*res = file;
-	return filp_close(file, files);
+	return 0;
 
 out_unlock:
 	spin_unlock(&files->file_lock);
@@ -706,29 +708,79 @@ void do_close_on_exec(struct files_struct *files)
 	spin_unlock(&files->file_lock);
 }
 
-static struct file *__fget(unsigned int fd, fmode_t mask, unsigned int refs)
+static inline struct file *__fget_files_rcu(struct files_struct *files,
+                                            unsigned int fd, fmode_t mask, unsigned int refs)
+{
+	for (;;) {
+		struct file *file;
+		struct fdtable *fdt = rcu_dereference_raw(files->fdt);
+		struct file __rcu **fdentry;
+
+		if (unlikely(fd >= fdt->max_fds))
+			return NULL;
+
+		fdentry = fdt->fd + array_index_nospec(fd, fdt->max_fds);
+		file = rcu_dereference_raw(*fdentry);
+		if (unlikely(!file))
+			return NULL;
+
+		if (unlikely(file->f_mode & mask))
+			return NULL;
+
+		/*
+		 * Ok, we have a file pointer. However, because we do
+		 * this all locklessly under RCU, we may be racing with
+		 * that file being closed.
+		 *
+		 * Such a race can take two forms:
+		 *
+		 *  (a) the file ref already went down to zero,
+		 *      and get_file_rcu_many() fails. Just try
+		 *      again:
+		 */
+		if (unlikely(!get_file_rcu_many(file, refs)))
+			continue;
+
+		/*
+		 *  (b) the file table entry has changed under us.
+		 *       Note that we don't need to re-check the 'fdt->fd'
+		 *       pointer having changed, because it always goes
+		 *       hand-in-hand with 'fdt'.
+		 *
+		 * If so, we need to put our refs and try again.
+		 */
+		if (unlikely(rcu_dereference_raw(files->fdt) != fdt) ||
+		    unlikely(rcu_dereference_raw(*fdentry) != file)) {
+			fput_many(file, refs);
+			continue;
+		}
+
+		/*
+		 * Ok, we have a ref to the file, and checked that it
+		 * still exists.
+		 */
+		return file;
+	}
+}
+
+static struct file *__fget_files(struct files_struct *files, unsigned int fd,
+				 fmode_t mask, unsigned int refs)
 {
-	struct files_struct *files = current->files;
 	struct file *file;
 
 	rcu_read_lock();
-loop:
-	file = fcheck_files(files, fd);
-	if (file) {
-		/* File object ref couldn't be taken.
-		 * dup2() atomicity guarantee is the reason
-		 * we loop to catch the new file (or NULL pointer)
-		 */
-		if (file->f_mode & mask)
-			file = NULL;
-		else if (!get_file_rcu_many(file, refs))
-			goto loop;
-	}
+	file = __fget_files_rcu(files, fd, mask, refs);
 	rcu_read_unlock();
 
 	return file;
 }
 
+static inline struct file *__fget(unsigned int fd, fmode_t mask,
+				  unsigned int refs)
+{
+	return __fget_files(current->files, fd, mask, refs);
+}
+
 struct file *fget_many(unsigned int fd, unsigned int refs)
 {
 	return __fget(fd, FMODE_PATH, refs);
@@ -746,6 +798,18 @@ struct file *fget_raw(unsigned int fd)
 }
 EXPORT_SYMBOL(fget_raw);
 
+struct file *fget_task(struct task_struct *task, unsigned int fd)
+{
+	struct file *file = NULL;
+
+	task_lock(task);
+	if (task->files)
+		file = __fget_files(task->files, fd, 0, 1);
+	task_unlock(task);
+
+	return file;
+}
+
 /*
  * Lightweight file lookup - no refcnt increment if fd table isn't shared.
  *

include/linux/file.h

@@ -16,6 +16,7 @@ extern void fput(struct file *);
 extern void fput_many(struct file *, unsigned int);
 
 struct file_operations;
+struct task_struct;
 struct vfsmount;
 struct dentry;
 struct inode;
@@ -47,6 +48,7 @@ static inline void fdput(struct fd fd)
 extern struct file *fget(unsigned int fd);
 extern struct file *fget_many(unsigned int fd, unsigned int refs);
 extern struct file *fget_raw(unsigned int fd);
+extern struct file *fget_task(struct task_struct *task, unsigned int fd);
 extern unsigned long __fdget(unsigned int fd);
 extern unsigned long __fdget_raw(unsigned int fd);
 extern unsigned long __fdget_pos(unsigned int fd);

mm/slub.c

@@ -282,7 +282,7 @@ static inline void *get_freepointer(struct kmem_cache *s, void *object)
 
 static void prefetch_freepointer(const struct kmem_cache *s, void *object)
 {
-	prefetch(object + s->offset);
+	prefetchw(object + s->offset);
 }
 
 static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)

package/default/config.default

@@ -700,7 +700,8 @@ CONFIG_OPROFILE_EVENT_MULTIPLEX=y
 CONFIG_HAVE_OPROFILE=y
 CONFIG_OPROFILE_NMI_TIMER=y
 CONFIG_KPROBES=y
-# CONFIG_JUMP_LABEL is not set
+CONFIG_JUMP_LABEL=y
+# CONFIG_STATIC_KEYS_SELFTEST is not set
 CONFIG_OPTPROBES=y
 CONFIG_KPROBES_ON_FTRACE=y
 CONFIG_UPROBES=y
@@ -4995,7 +4996,7 @@ CONFIG_RCU_CPU_STALL_TIMEOUT=60
 # CONFIG_NOTIFIER_ERROR_INJECTION is not set
 CONFIG_FUNCTION_ERROR_INJECTION=y
 # CONFIG_FAULT_INJECTION is not set
-CONFIG_LATENCYTOP=y
+# CONFIG_LATENCYTOP is not set
 CONFIG_USER_STACKTRACE_SUPPORT=y
 CONFIG_NOP_TRACER=y
 CONFIG_HAVE_FUNCTION_TRACER=y