[PATCH 05/10] AXFS: axfs_profiling.c

[Jared Hulbert <jaredeh@gmail.com>]

Profiling is a fault instrumentation and /proc formating system.
This is used to get an accurate picture of what the pages are actually used.
Using this info the image can be optimized for XIP

Signed-off-by: Jared Hulbert <jaredeh@gmail.com>
---
diff --git a/fs/axfs/axfs_profiling.c b/fs/axfs/axfs_profiling.c
new file mode 100644
index 0000000..30d881c
--- /dev/null
+++ b/fs/axfs/axfs_profiling.c
@@ -0,0 +1,594 @@
+/*
+ * Advanced XIP File System for Linux - AXFS
+ *   Readonly, compressed, and XIP filesystem for Linux systems big and small
+ *
+ * Copyright(c) 2008 Numonyx
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * Authors:
+ *  Eric Anderson
+ *  Jared Hulbert <jaredeh@gmail.com>
+ *  Sujaya Srinivasan
+ *  Justin Treon
+ *
+ * More info and current contacts at http://axfs.sourceforge.net
+ *
+ * axfs_profiling.c -
+ *   Tracks pages of files that enter the page cache.  Outputs through a proc
+ *   file which generates a comma separated data file with path, page offset,
+ *   count of times entered page cache.
+ */
+
+#include <linux/axfs.h>
+#ifdef CONFIG_AXFS_PROFILING
+#include <linux/module.h>
+#include <linux/vmalloc.h>
+#include <linux/proc_fs.h>
+
+#define AXFS_PROC_DIR_NAME "axfs"
+
+struct axfs_profiling_manager {
+	struct axfs_profiling_data *profiling_data;
+	struct axfs_super *sbi;
+	u32 *dir_structure;
+	u32 size;
+};
+
+#define MAX_STRING_LEN 1024
+
+/* Handles for our Directory and File */
+static struct proc_dir_entry *axfs_proc_dir;
+static u32 proc_name_inc;
+
+/******************************************************************************
+ *
+ * axfs_init_profile_dir_structure
+ *
+ * Description:
+ *   Creates the structures for tracking the page usage data and creates the
+ *   proc file that will be used to get the data.
+ *
+ * Parameters:
+ *    (IN) manager - pointer to the profile manager for the filing system
+ *
+ *    (IN) num_inodes - number of files in the system
+ *
+ * Returns:
+ *    0
+ *
+ *****************************************************************************/
+static int axfs_init_profile_dir_structure(struct axfs_profiling_manager
+					   *manager, u32 num_inodes)
+{
+
+	struct axfs_super *sbi = (struct axfs_super *)manager->sbi;
+	u32 child_index = 0, i, j;
+	u32 *dir_structure = manager->dir_structure;
+
+	/* loop through each inode in the image and find all
+	   of the directories and mark their children */
+	for (i = 0; i < num_inodes; i++) {
+		/* determine if the entry is a directory */
+		if (!S_ISDIR(AXFS_GET_MODE(sbi, i)))
+			continue;
+
+		/* get the index number for this directory */
+		child_index = AXFS_GET_INODE_ARRAY_INDEX(sbi, i);
+
+		/* get the offset to its children */
+		for (j = 0; j < AXFS_GET_INODE_NUM_ENTRIES(sbi, i); j++) {
+			if (dir_structure[child_index + j] != 0) {
+				printk(KERN_ERR
+				       "axfs: ERROR inode was already set old "
+				       "%lu new %lu\n", (unsigned long)
+				       dir_structure[child_index + j],
+				       (unsigned long)i);
+			}
+			dir_structure[child_index + j] = i;
+		}
+	}
+
+	return 0;
+}
+
+/******************************************************************************
+ *
+ * axfs_get_directory_path
+ *
+ * Description:
+ *   Determines the directory path of every file for printing the spreadsheet.
+ *
+ * Parameters:
+ *    (IN) manager - Pointer to axfs profile manager
+ *
+ *    (OUT) buffer - Pointer to the printable directory path for each file
+ *
+ *    (IN) inode_number - Inode number of file to look up
+ *
+ * Returns:
+ *    Size of the path to the file
+ *
+ *
+ **************************************************************************/
+static int axfs_get_directory_path(struct axfs_profiling_manager *manager,
+				   char *buffer, u32 inode_number)
+{
+	u32 path_depth = 0;
+	u32 path_size = 0;
+	u32 string_len = 0;
+	u32 index = inode_number;
+	u32 dir_number;
+	u8 **path_array = NULL;
+	struct axfs_super *sbi = (struct axfs_super *)manager->sbi;
+	int i;
+
+	/* determine how deep the directory path is and how big the name
+	   string will be walk back until the root directory index is found
+	   (index 0 is root) */
+	while (manager->dir_structure[index] != 0) {
+		path_depth++;
+		/* set the index to the index of the parent directory */
+		index = manager->dir_structure[index];
+	}
+
+	if (path_depth != 0) {
+		/* create an array that will hold a pointer for each of the
+		   directories names */
+		path_array = vmalloc(path_depth * sizeof(*path_array));
+		if (path_array == NULL) {
+			printk(KERN_DEBUG
+			       "axfs: directory_path vmalloc failed.\n");
+			goto out;
+		}
+	}
+
+	index = manager->dir_structure[inode_number];
+	for (i = path_depth; i > 0; i--) {
+		/* get the array_index for the directory corresponding to
+		   index */
+		dir_number = AXFS_GET_INODE_ARRAY_INDEX(sbi, index);
+
+		/* store a pointer to the name in the array */
+		path_array[(i - 1)] = (u8 *) AXFS_GET_INODE_NAME(sbi, index);
+
+		index = manager->dir_structure[index];
+	}
+
+	/* now print out the directory structure from the begining */
+	string_len = sprintf(buffer, "./");
+	path_size += string_len;
+	for (i = 0; i < path_depth; i++) {
+		buffer = buffer + string_len;
+		string_len = sprintf(buffer, "%s/", (char *)path_array[i]);
+		path_size += string_len;
+	}
+
+	if (path_array != NULL)
+		vfree(path_array);
+
+out:
+	return path_size;
+
+}
+
+static ssize_t axfs_procfile_read(char *buffer,
+				  char **buffer_location,
+				  off_t offset, int buffer_length, int *eof,
+				  void *data)
+{
+	struct axfs_profiling_manager *man;
+	struct axfs_profiling_data *profile;
+	struct axfs_super *sbi;
+	u64 array_index;
+	u64 loop_size, inode_page_offset, node_offset, inode_number;
+	u64 print_len = 0;
+	unsigned long addr;
+	int len = 0;
+	int i;
+	char *buff, *name = NULL;
+
+	man = (struct axfs_profiling_manager *)data;
+	sbi = man->sbi;
+
+	loop_size = man->size / sizeof(*profile);
+
+	/* If all data has been returned set EOF */
+	if (offset >= loop_size) {
+		*eof = 1;
+		return 0;
+	}
+
+	buff = buffer;
+	/* print as much as the buffer can take */
+	for (i = offset; i < loop_size; i++) {
+
+		if ((print_len + MAX_STRING_LEN) > buffer_length)
+			break;
+		/* get the first profile data structure */
+		profile = &(man->profiling_data[i]);
+
+		if (profile->count == 0)
+			continue;
+
+		inode_number = profile->inode_number;
+
+		/* file names can be duplicated so we must print out the path */
+		len = axfs_get_directory_path(man, buff, inode_number);
+
+		print_len += len;
+		buff += len;
+
+		/* get a pointer to the inode name */
+		array_index = AXFS_GET_INODE_ARRAY_INDEX(sbi, inode_number);
+		name = (char *)AXFS_GET_INODE_NAME(sbi, inode_number);
+
+		/* need to convert the page number in the node area to
+		   the page number within the file */
+		node_offset = i;
+		/* gives the offset of the node in the node list area
+		   then substract that from the */
+		inode_page_offset = node_offset - array_index;
+
+		/* set everything up to print out */
+		addr = (unsigned long)(inode_page_offset * PAGE_SIZE);
+		len = sprintf(buff, "%s,%lu,%lu\n", name, addr, profile->count);
+
+		print_len += len;
+		buff += len;
+	}
+
+	/* return the number of items printed.
+	   This will be added to offset and passed back to us */
+	*buffer_location = (char *)(i - offset);
+
+	return print_len;
+}
+
+static ssize_t axfs_procfile_write(struct file *file,
+				   const char *buffer, unsigned long count,
+				   void *data)
+{
+	struct axfs_profiling_manager *man_ptr =
+	    (struct axfs_profiling_manager *)data;
+
+	if ((count >= 2) && (0 == memcmp(buffer, "on", 2))) {
+		man_ptr->sbi->profiling_on = TRUE;
+	} else if ((count >= 3) && (0 == memcmp(buffer, "off", 3))) {
+		man_ptr->sbi->profiling_on = FALSE;
+	} else if ((count >= 5) && (0 == memcmp(buffer, "clear", 5))) {
+		memset(man_ptr->profiling_data, 0, man_ptr->size);
+	} else {
+		printk(KERN_INFO
+		       "axfs: Unknown command.  Supported options are:\n");
+		printk(KERN_INFO "\t\"on\"\tTurn on profiling\n");
+		printk(KERN_INFO "\t\"off\"\tTurn off profiling\n");
+		printk(KERN_INFO "\t\"clear\"\tClear profiling buffer\n");
+	}
+
+	return count;
+}
+
+static int axfs_create_proc_directory(void)
+{
+	if (axfs_proc_dir == NULL) {
+		axfs_proc_dir = proc_mkdir(AXFS_PROC_DIR_NAME, NULL);
+		if (!axfs_proc_dir) {
+			printk(KERN_WARNING
+			       "axfs: Failed to create directory\n");
+			return FALSE;
+		}
+	}
+	return TRUE;
+}
+
+static void axfs_delete_proc_directory(void)
+{
+	/* Determine if there are any directory elements
+	   and remove if all of the proc files are removed. */
+	if (axfs_proc_dir != NULL) {
+		if (axfs_proc_dir->subdir == NULL) {
+			remove_proc_entry(AXFS_PROC_DIR_NAME, NULL);
+			axfs_proc_dir = NULL;
+		}
+	}
+}
+
+/******************************************************************************
+ *
+ * axfs_delete_proc_file
+ *
+ * Description:
+ *   Will search through the proc directory for the correct proc file,
+ *   then delete it
+ *
+ * Parameters:
+ *    (IN) sbi- axfs superblock pointer to determine which proc file to remove
+ *
+ * Returns:
+ *    The profiling manager pointer for the proc file.
+ *
+ *****************************************************************************/
+static struct axfs_profiling_manager *axfs_delete_proc_file(struct axfs_super
+							    *sbi)
+{
+	struct proc_dir_entry *current_proc_file;
+	struct axfs_profiling_manager *manager;
+	void *rv = NULL;
+
+	if (!axfs_proc_dir)
+		return NULL;
+
+	/* Walk through the proc file entries to find the matching sbi */
+	current_proc_file = axfs_proc_dir->subdir;
+
+	while (current_proc_file != NULL) {
+		manager = current_proc_file->data;
+		if (manager == NULL) {
+			printk(KERN_WARNING
+			       "axfs: Error removing proc file private "
+			       "data was NULL.\n");
+			rv = NULL;
+			break;
+		}
+		if (manager->sbi == sbi) {
+			/* we found the match */
+			remove_proc_entry(current_proc_file->name,
+					  axfs_proc_dir);
+			rv = (void *)manager;
+			break;
+		}
+		current_proc_file = axfs_proc_dir->next;
+	}
+	return (struct axfs_profiling_manager *)rv;
+}
+
+/******************************************************************************
+ *
+ * axfs_register_profiling_proc
+ *
+ * Description:
+ *   Will register the instance of the proc file for a given volume.
+ *
+ * Parameters:
+ *    (IN) manager - Pointer to the profiling manager for the axfs volume
+ *
+ * Returns:
+ *    0 or error number
+ *
+ *****************************************************************************/
+static int axfs_register_profiling_proc(struct axfs_profiling_manager *manager)
+{
+	int rv = 0;
+	struct proc_dir_entry *proc_file;
+	char file_name[20];
+
+	if (!axfs_create_proc_directory()) {
+		rv = -ENOMEM;
+		goto out;
+	}
+
+	sprintf(file_name, "volume%d", proc_name_inc);
+	proc_file = create_proc_entry(file_name, (mode_t) 0644, axfs_proc_dir);
+	if (proc_file == NULL) {
+		remove_proc_entry(file_name, axfs_proc_dir);
+		axfs_delete_proc_directory();
+		rv = -ENOMEM;
+		goto out;
+	}
+
+	proc_name_inc++;
+	proc_file->read_proc = axfs_procfile_read;
+	proc_file->write_proc = axfs_procfile_write;
+	proc_file->owner = THIS_MODULE;
+	proc_file->mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
+	proc_file->uid = 0;
+	proc_file->gid = 0;
+	proc_file->data = manager;
+
+	printk(KERN_DEBUG "axfs: Proc entry created\n");
+
+out:
+	return rv;
+}
+
+/******************************************************************************
+ *
+ * axfs_unregister_profiling_proc
+ *
+ * Description:
+ *   Will unregister the instance of the proc file for the volume that was
+ *   mounted.  If this is the last volume mounted then the proc directory
+ *   will also be removed.
+ *
+ * Parameters:
+ *    (IN) sbi- axfs superblock pointer to determine which proc file to remove
+ *
+ * Returns:
+ *    The profiling manager pointer for the proc file.
+ *
+ *****************************************************************************/
+static struct axfs_profiling_manager *axfs_unregister_profiling_proc(struct
+								     axfs_super
+								     *sbi)
+{
+	struct axfs_profiling_manager *manager;
+	manager = axfs_delete_proc_file(sbi);
+	axfs_delete_proc_directory();
+	return manager;
+}
+
+/******************************************************************************
+ *
+ * axfs_init_profiling
+ *
+ * Description:
+ *   Creates the structures for tracking the page usage data and creates the
+ *   proc file that will be used to get the data.
+ *
+ * Parameters:
+ *    (IN) sbi- axfs superblock pointer
+ *
+ * Returns:
+ *    TRUE or FALSE
+ *
+ *****************************************************************************/
+int axfs_init_profiling(struct axfs_super *sbi)
+{
+
+	u32 num_nodes, num_inodes;
+	struct axfs_profiling_manager *manager = NULL;
+	struct axfs_profiling_data *profile_data = NULL;
+	int err = -ENOMEM;
+
+	/* determine the max number of pages in the FS */
+	num_nodes = sbi->blocks;
+	if (!num_nodes)
+		return 0;
+
+	manager = vmalloc(sizeof(*manager));
+	if (!manager)
+		goto out;
+
+	profile_data = vmalloc(num_nodes * sizeof(*profile_data));
+	if (!profile_data)
+		goto out;
+
+	memset(profile_data, 0, num_nodes * sizeof(*profile_data));
+
+	/* determine the max number of inodes in the FS */
+	num_inodes = sbi->files;
+
+	manager->dir_structure = vmalloc(num_inodes * sizeof(u32 *));
+	if (!manager->dir_structure)
+		goto out;
+
+	memset(manager->dir_structure, 0, (num_inodes * sizeof(u32 *)));
+
+	manager->profiling_data = profile_data;
+	manager->size = num_nodes * sizeof(*profile_data);
+	manager->sbi = sbi;
+	sbi->profiling_on = TRUE;	/* Turn on profiling by default */
+	sbi->profile_data_ptr = profile_data;
+
+	err = axfs_init_profile_dir_structure(manager, num_inodes);
+	if (err)
+		goto out;
+
+	err = axfs_register_profiling_proc(manager);
+	if (err)
+		goto out;
+
+	return 0;
+
+out:
+	if (manager->dir_structure)
+		vfree(manager->dir_structure);
+	if (profile_data)
+		vfree(profile_data);
+	if (manager)
+		vfree(manager);
+	return err;
+}
+
+/******************************************************************************
+ *
+ * axfs_shutdown_profiling
+ *
+ * Description:
+ *   Remove the proc file for this volume and release the memory in the
+ *   profiling manager
+ *
+ * Parameters:
+ *    (IN) sbi- axfs superblock pointer
+ *
+ * Returns:
+ *    TRUE or FALSE
+ *
+ *****************************************************************************/
+int axfs_shutdown_profiling(struct axfs_super *sbi)
+{
+	struct axfs_profiling_manager *manager;
+	/* remove the proc file for this volume and release the memory in the
+	   profiling manager */
+
+	if (!sbi)
+		return TRUE;
+
+	if (!sbi->profile_data_ptr)
+		return TRUE;
+
+	manager = axfs_unregister_profiling_proc(sbi);
+
+	if (manager == NULL)
+		return FALSE;
+
+	if (manager->dir_structure)
+		vfree(manager->dir_structure);
+	if (manager->profiling_data)
+		vfree(manager->profiling_data);
+	if (manager)
+		vfree(manager);
+	return TRUE;
+}
+
+/******************************************************************************
+ *
+ * axfs_profiling_add
+ *
+ * Description:
+ *    Log when a node is paged into memory by incrementing the count in the
+ *    array profile data structure.
+ *
+ * Parameters:
+ *    (IN) sbi- axfs superblock pointer
+ *
+ *    (IN) array_index - The offset into the nodes table of file (node number)
+ *
+ *    (IN) axfs_inode_number - Inode of the node to determine file name later
+ *
+ * Returns:
+ *    none
+ *
+ *****************************************************************************/
+void axfs_profiling_add(struct axfs_super *sbi, unsigned long array_index,
+			unsigned int axfs_inode_number)
+{
+	unsigned long addr;
+	struct axfs_profiling_data *profile_data;
+
+	if (sbi->profiling_on != TRUE)
+		return;
+
+	addr = (unsigned long)sbi->profile_data_ptr;
+	addr += array_index * sizeof(*profile_data);
+
+	profile_data = (struct axfs_profiling_data *)addr;
+
+	/* Record the inode number to determine the file name later. */
+	profile_data->inode_number = axfs_inode_number;
+
+	/* Increment the number of times the node has been paged in */
+	profile_data->count++;
+}
+
+#else
+
+int axfs_init_profiling(struct axfs_super *sbi)
+{
+	return 0;
+}
+
+int axfs_shutdown_profiling(struct axfs_super *sbi)
+{
+	return 0;
+}
+
+void axfs_profiling_add(struct axfs_super *sbi, unsigned long array_index,
+			unsigned int axfs_inode_number)
+{
+}
+
+#endif /* CONFIG_AXFS_PROFILING */