Merge pull request #17 from natsys/sched/rr

The round-robin scheduler implementation.

tempesta.sh

@@ -7,6 +7,7 @@
 SSOCKET=sync_socket
 TDB=tempesta_db
 TFW=tempesta_fw
+SCHED=tfw_sched_dummy
 TFW_ROOT=`pwd`/$TFW
 TFW_CACHE_SIZE=`expr 256 \* 1024`
 TFW_CACHE_PATH=$TFW_ROOT/cache
@@ -44,6 +45,9 @@ start()
 				 cache_path="$TFW_CACHE_PATH"
 	[ $? -ne 0 ] && error "cannot load tempesta module"
 
+	insmod $TFW_ROOT/sched/$SCHED.ko
+	[ $? -ne 0 ] && error "cannot load scheduler module"
+
 	sysctl --load=tempesta.sysctl.conf
 	[ $? -ne 0 ] && error "cannot apply configuration via sysctl"
 

tempesta_fw/Makefile

@@ -22,6 +22,6 @@ obj-m	= tempesta_fw.o
 tempesta_fw-objs = cache.o classifier.o client.o connection.o filter.o gfsm.o \
 		   http.o http_msg.o http_parser.o if.o lib.o main.o pool.o \
 		   sched.o server.o session.o sock_backend.o sock_frontend.o \
-		   stress.o
+		   stress.o debugfs.o
 
 obj-m	+= log/ classifier/ stress/ sched/ filter/

tempesta_fw/debugfs.c

@@ -0,0 +1,369 @@
+/**
+ *		Tempesta FW
+ *
+ * Copyright (C) 2012-2014 NatSys Lab. (info@natsys-lab.com).
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59
+ * Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/string.h>
+
+#include "debugfs.h"
+#include "log.h"
+#include "tempesta.h"
+
+
+#ifdef DEBUG
+
+/* The root directory for the Tempesta debugfs module.
+ * All paths are referenced relative to this root. */
+struct dentry *tfw_debugfs_root;
+
+/* Name of the directory which is created in the debugfs upon initialization. */
+#define TFW_DEBUGFS_ROOT_NAME "tempesta"
+
+/**
+ * Initialize the debugfs wrapper by creating a directory in the debugfs
+ * where all files owned by the Tempesta FW are hosted.
+ */
+int
+tfw_debugfs_init(void)
+{
+	int ret = 0;
+
+	tfw_debugfs_root = debugfs_create_dir(TFW_DEBUGFS_ROOT_NAME, NULL);
+
+	if (IS_ERR_OR_NULL(tfw_debugfs_root)) {
+		ret = (int)PTR_ERR(tfw_debugfs_root);
+		TFW_WARN("Can't create debugfs directory (%d)\n", ret);
+	}
+
+	return ret;
+}
+
+/**
+ * Delete the Tempesta's debugfs directory with all files recursively.
+ */
+void
+tfw_debugfs_exit(void)
+{
+	if (tfw_debugfs_root) {
+		debugfs_remove_recursive(tfw_debugfs_root);
+		tfw_debugfs_root = NULL;
+	}
+}
+
+/**
+ * Look up for a file (or directory) in VFS.
+ */
+static struct dentry *
+lookup_file(const char *path, struct dentry *parent)
+{
+	int ret;
+	struct path p;
+
+	BUG_ON(!parent);
+	ret = vfs_path_lookup(parent, NULL, path, 0, &p);
+
+	return (ret ? NULL : p.dentry);
+}
+
+/**
+ * Create a file in the debugfs, also create parent directories if needed and
+ * remove the old file if it exists.
+ *
+ * @param path  Path to a file to be created.
+ *              The path is always treated relative to the Tempesta root
+ *              directory in the debugfs (see tfw_debugfs_root).
+ * @param data  A pointer to some data which is saved in 'file' and 'inode'
+ *              structures. It may be retrieved by any function in @fops as
+ *              file->private_data or file->f_inode->i_private (it is copied
+ *              into both places).
+ * @param fops  A set of functions that handle system calls on the created file.
+ *
+ *
+ * The function creates a file in the debugfs, but does it in a robust way:
+ *  - the file is replaced if it already exists
+ *  - all parent directories are created if they don't exist
+ *
+ * Returns: An ERR_PTR if the file is not created.
+ */
+static struct dentry *
+create_with_parents(const char *path, void *data,
+		    const struct file_operations *fops)
+{
+	size_t name_size;
+	char *buf, *pos, *component;
+	struct dentry *parent, *child;
+
+	/* Copy the path to a temporary buffer where it can be modified. */
+	name_size = strlen(path) + 1;
+	buf = kmalloc(name_size, GFP_KERNEL);
+	BUG_ON(ZERO_OR_NULL_PTR(buf));
+	strlcpy(buf, path, name_size);
+
+	/* Eat the leading slash to allow specify either /foo/bar or foo/bar */
+	pos = buf;
+	if (*pos == '/')
+		++pos;
+
+	/* Walk over the path and create non-existing directories. */
+	parent = tfw_debugfs_root;
+	component = pos;
+	do {
+		if (*pos != '/')
+			continue;
+
+		*pos = '\0';
+		child = lookup_file(component, parent);
+		if (!child) {
+			child = debugfs_create_dir(component, parent);
+			BUG_ON(!parent);
+		}
+		parent = child;
+		component = pos + 1;
+	} while (*(++pos));
+
+	/* Remove the file if it already exists. */
+	child = lookup_file(component, parent);
+	if (child) {
+		TFW_DBG("Removing already existing debugfs file: %s\n", path);
+		debugfs_remove(child);
+	}
+
+	/* Create the actual file. */
+	child = debugfs_create_file(component, S_IRWXU, parent, data, fops);
+	if (IS_ERR_OR_NULL(child)) {
+		int err = PTR_ERR(child);
+		TFW_WARN("Can't create debugfs file: %s (%d)\n", path, err);
+	} else {
+		TFW_DBG("Created debugfs file: %s\n", path);
+	}
+
+	kfree(buf);
+
+	return child;
+}
+
+/**
+ * A state maintained between open() and release() calls.
+ *
+ * Usage of this structure depens on the data direction:
+ *
+ * 1. If a file is open()'ed for reading (@is_input is false):
+ * - open() allocates the @buf and invokes a callback that writes data to it.
+ * - read() just copies data from the @buf to the user-space.
+ * - write() returns an error.
+ * - close() releases all the allocated memory.
+ *
+ * 2. If a file is open()'ed for writing (@is_input is true):
+ * - open() allocates the @buf
+ * - read() returns an error.
+ * - write() copies data from user-space to the @buf.
+ * - close() invokes a callback passing the @buf to it and releases the memory.
+ *
+ * The file may be open()'ed only for either reading or writing but not both.
+ */
+typedef struct {
+	bool is_input;
+	int len;
+	int buf_size;
+	char *buf;
+} TfwDebugfsIoState;
+
+static int
+fop_open(struct inode *inode, struct file *file)
+{
+	fmode_t mode = file->f_mode;
+	tfw_debugfs_handler_t fn = file->f_inode->i_private;
+	TfwDebugfsIoState *state;
+
+	if ((mode & FMODE_READ) && (mode & FMODE_WRITE)) {
+		TFW_ERR("This debugfs file can't be opened in read-write mode");
+		return -EPERM;
+	}
+
+	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	BUG_ON(!state);
+
+	/* Simply allocate a fixed-size buffer. The buffer doesn't expand, the
+	 * data is cropped if it doesn't fit to it. Later on we may change it */
+	state->buf_size = PAGE_SIZE;
+	state->buf = kmalloc(state->buf_size, GFP_KERNEL);
+	BUG_ON(!state->buf);
+
+	if (mode & FMODE_WRITE)
+		state->is_input = true;
+	else
+		state->len = fn(state->is_input, state->buf, state->buf_size);
+
+	file->private_data = state;
+
+	return 0;
+}
+
+static ssize_t
+fop_read(struct file *file, char __user *user_buf, size_t count,
+	 loff_t *ppos)
+{
+	TfwDebugfsIoState *state = file->private_data;
+
+	if (state->is_input) {
+		TFW_ERR("Can't read this debugfs file: "
+			"it was open()'ed only for writing\n");
+		return -EPERM;
+	}
+
+	if (state->len < 0)
+		return state->len;
+
+	return simple_read_from_buffer(user_buf, count, ppos,
+				       state->buf,
+				       state->len);
+}
+
+static ssize_t
+fop_write(struct file *file, const char __user *user_buf,
+	  size_t count,
+	  loff_t *ppos)
+{
+	int len;
+	TfwDebugfsIoState *state = file->private_data;
+
+	if (!state->is_input) {
+		TFW_ERR("Can't write to this debugfs file: "
+			"it was open()'ed only for reading\n");
+		return -EPERM;
+	}
+
+	/* copy data from user-space */
+	len = simple_write_to_buffer(state->buf, (state->buf_size - 1),
+				     ppos,
+				     user_buf, count);
+	if (len > 0) {
+		state->len += len;
+		state->buf[state->len] = '\0';
+	}
+
+	return len;
+}
+
+static int
+fop_release(struct inode *inode, struct file *file)
+{
+	int ret = 0;
+	tfw_debugfs_handler_t fn = file->f_inode->i_private;
+	TfwDebugfsIoState *state = file->private_data;
+
+	if (state->is_input)
+		ret = fn(state->is_input, state->buf, state->len);
+
+	kfree(state->buf);
+	kfree(state);
+
+	return ret;
+}
+
+/**
+ * Create a file in debugfs and bind a function with it.
+ *
+ * @path  Path to of a file to be created.
+ *        The path is always treated as relative to tempesta root directory
+ *        in the debugfs. The file may exist, in this case it will be replaced.
+ *        Parent directories may not exist (they will be created automatically).
+ * @fn    A function that handles I/O (that is either receives or sends data to
+ *        user-space).
+ *
+ * This function allows to bind a file (that may be read/written in user-space)
+ * with a function (that works in kernel-space).
+ *
+ * Consider the following example:
+ *
+ * int my_io_handler(bool is_input, char *buf, size_t size)
+ * {
+ *         if (is_input) {
+ *                 printk("got input data from user-space: %.*s", size, buf);
+ *                 return 0;
+ *         } else {
+ *                 return snprintf("hello from kernel-space!\n");
+ *         }
+ * }
+ *
+ * tfw_debugfs_bind("/foo/bar", my_io_handler);
+ *
+ * The code binds the file /foo/bar with the function my_io_handler() and allows
+ * to interact with the kernel function from a user-space shell like this:
+ *   $ cat /sys/kernel/debug/tempesta/foo/bar
+ *   hello from kernel-space!
+ *   $ echo "hi from user-space" > /sys/kernel/debug/tempesta/foo/bar
+ *   $ dmesg | head -n1
+ *   got input data from user-space: hi from user-space
+ *
+ * When the file is open()'ed in read mode, the my_io_handler() is called with
+ * is_input=false. In this case the function is requested to put some data to
+ * the buffer. The buffer then is saved and returned to user-space during
+ * subsequent read() calls until the file is close()'d.
+ *
+ * When the file is open()'ed in write mode, the data is accumulated in the
+ * buffer during write() calls. When the file is close()'d, the my_io_handler()
+ * is called to take the data received from user-space.
+ *
+ * Therefore, the handler function doesn't need to care about streaming, it
+ * receives or sends the data "atomically" with a single big chunk.
+ * This approach simplifies your code (no need to preserve state between calls),
+ * but it is not very effective, so don't use it for large amounts of data.
+ *
+ * @return A status code: 0 if the file is created, -1 otherwise.
+ */
+int
+tfw_debugfs_bind(const char *path, tfw_debugfs_handler_t fn)
+{
+	static const struct file_operations fops = {
+		.llseek = default_llseek,
+		.open = fop_open,
+		.read = fop_read,
+		.write = fop_write,
+		.release = fop_release,
+	};
+	struct dentry *d;
+
+	BUG_ON(!path || !fn);
+	d = create_with_parents(path, fn, &fops);
+
+	return IS_ERR_OR_NULL(d) ? -1 : 0;
+}
+EXPORT_SYMBOL(tfw_debugfs_bind);
+
+#else /* ifdef DEBUG */
+
+int tfw_debugfs_bind(const char *path, tfw_debugfs_handler_t handler_fn)
+{
+	return 0;
+}
+EXPORT_SYMBOL(tfw_debugfs_bind);
+
+int tfw_debugfs_init(void)
+{
+	return 0;
+}
+
+void tfw_debugfs_exit(void)
+{
+}
+
+#endif /* ifndef DEBUG */