1 files changed, 333 insertions, 0 deletions
diff --git a/mm/kmemtrace.c b/mm/kmemtrace.c
new file mode 100644
index 000000000000..2a70a805027c
--- /dev/null
+++ b/mm/kmemtrace.c
@@ -0,0 +1,333 @@
+/*
+ * Copyright (C) 2008 Pekka Enberg, Eduard - Gabriel Munteanu
+ *
+ * This file is released under GPL version 2.
+ */
+
+#include <linux/string.h>
+#include <linux/debugfs.h>
+#include <linux/relay.h>
+#include <linux/module.h>
+#include <linux/marker.h>
+#include <linux/gfp.h>
+#include <linux/kmemtrace.h>
+
+#define KMEMTRACE_SUBBUF_SIZE		524288
+#define KMEMTRACE_DEF_N_SUBBUFS		20
+
+static struct rchan *kmemtrace_chan;
+static u32 kmemtrace_buf_overruns;
+
+static unsigned int kmemtrace_n_subbufs;
+
+/* disabled by default */
+static unsigned int kmemtrace_enabled;
+
+/*
+ * The sequence number is used for reordering kmemtrace packets
+ * in userspace, since they are logged as per-CPU data.
+ *
+ * atomic_t should always be a 32-bit signed integer. Wraparound is not
+ * likely to occur, but userspace can deal with it by expecting a certain
+ * sequence number in the next packet that will be read.
+ */
+static atomic_t kmemtrace_seq_num;
+
+#define KMEMTRACE_ABI_VERSION		1
+
+static u32 kmemtrace_abi_version __read_mostly = KMEMTRACE_ABI_VERSION;
+
+enum kmemtrace_event_id {
+	KMEMTRACE_EVENT_ALLOC = 0,
+	KMEMTRACE_EVENT_FREE,
+};
+
+struct kmemtrace_event {
+	u8		event_id;
+	u8		type_id;
+	u16		event_size;
+	s32		seq_num;
+	u64		call_site;
+	u64		ptr;
+} __attribute__ ((__packed__));
+
+struct kmemtrace_stats_alloc {
+	u64		bytes_req;
+	u64		bytes_alloc;
+	u32		gfp_flags;
+	s32		numa_node;
+} __attribute__ ((__packed__));
+
+static void kmemtrace_probe_alloc(void *probe_data, void *call_data,
+				  const char *format, va_list *args)
+{
+	unsigned long flags;
+	struct kmemtrace_event *ev;
+	struct kmemtrace_stats_alloc *stats;
+	void *buf;
+
+	local_irq_save(flags);
+
+	buf = relay_reserve(kmemtrace_chan,
+			    sizeof(struct kmemtrace_event) +
+			    sizeof(struct kmemtrace_stats_alloc));
+	if (!buf)
+		goto failed;
+
+	/*
+	 * Don't convert this to use structure initializers,
+	 * C99 does not guarantee the rvalues evaluation order.
+	 */
+
+	ev = buf;
+	ev->event_id = KMEMTRACE_EVENT_ALLOC;
+	ev->type_id = va_arg(*args, int);
+	ev->event_size = sizeof(struct kmemtrace_event) +
+			 sizeof(struct kmemtrace_stats_alloc);
+	ev->seq_num = atomic_add_return(1, &kmemtrace_seq_num);
+	ev->call_site = va_arg(*args, unsigned long);
+	ev->ptr = va_arg(*args, unsigned long);
+
+	stats = buf + sizeof(struct kmemtrace_event);
+	stats->bytes_req = va_arg(*args, unsigned long);
+	stats->bytes_alloc = va_arg(*args, unsigned long);
+	stats->gfp_flags = va_arg(*args, unsigned long);
+	stats->numa_node = va_arg(*args, int);
+
+failed:
+	local_irq_restore(flags);
+}
+
+static void kmemtrace_probe_free(void *probe_data, void *call_data,
+				 const char *format, va_list *args)
+{
+	unsigned long flags;
+	struct kmemtrace_event *ev;
+
+	local_irq_save(flags);
+
+	ev = relay_reserve(kmemtrace_chan, sizeof(struct kmemtrace_event));
+	if (!ev)
+		goto failed;
+
+	/*
+	 * Don't convert this to use structure initializers,
+	 * C99 does not guarantee the rvalues evaluation order.
+	 */
+	ev->event_id = KMEMTRACE_EVENT_FREE;
+	ev->type_id = va_arg(*args, int);
+	ev->event_size = sizeof(struct kmemtrace_event);
+	ev->seq_num = atomic_add_return(1, &kmemtrace_seq_num);
+	ev->call_site = va_arg(*args, unsigned long);
+	ev->ptr = va_arg(*args, unsigned long);
+
+failed:
+	local_irq_restore(flags);
+}
+
+static struct dentry *
+kmemtrace_create_buf_file(const char *filename, struct dentry *parent,
+			  int mode, struct rchan_buf *buf, int *is_global)
+{
+	return debugfs_create_file(filename, mode, parent, buf,
+				   &relay_file_operations);
+}
+
+static int kmemtrace_remove_buf_file(struct dentry *dentry)
+{
+	debugfs_remove(dentry);
+
+	return 0;
+}
+
+static int kmemtrace_subbuf_start(struct rchan_buf *buf,
+				  void *subbuf,
+				  void *prev_subbuf,
+				  size_t prev_padding)
+{
+	if (relay_buf_full(buf)) {
+		/*
+		 * We know it's not SMP-safe, but neither
+		 * debugfs_create_u32() is.
+		 */
+		kmemtrace_buf_overruns++;
+		return 0;
+	}
+
+	return 1;
+}
+
+static struct rchan_callbacks relay_callbacks = {
+	.create_buf_file = kmemtrace_create_buf_file,
+	.remove_buf_file = kmemtrace_remove_buf_file,
+	.subbuf_start = kmemtrace_subbuf_start,
+};
+
+static struct dentry *kmemtrace_dir;
+static struct dentry *kmemtrace_overruns_dentry;
+static struct dentry *kmemtrace_abi_version_dentry;
+
+static struct dentry *kmemtrace_enabled_dentry;
+
+static int kmemtrace_start_probes(void)
+{
+	int err;
+
+	err = marker_probe_register("kmemtrace_alloc", "type_id %d "
+				    "call_site %lu ptr %lu "
+				    "bytes_req %lu bytes_alloc %lu "
+				    "gfp_flags %lu node %d",
+				    kmemtrace_probe_alloc, NULL);
+	if (err)
+		return err;
+	err = marker_probe_register("kmemtrace_free", "type_id %d "
+				    "call_site %lu ptr %lu",
+				    kmemtrace_probe_free, NULL);
+
+	return err;
+}
+
+static void kmemtrace_stop_probes(void)
+{
+	marker_probe_unregister("kmemtrace_alloc",
+				kmemtrace_probe_alloc, NULL);
+	marker_probe_unregister("kmemtrace_free",
+				kmemtrace_probe_free, NULL);
+}
+
+static int kmemtrace_enabled_get(void *data, u64 *val)
+{
+	*val = *((int *) data);
+
+	return 0;
+}
+
+static int kmemtrace_enabled_set(void *data, u64 val)
+{
+	u64 old_val = kmemtrace_enabled;
+
+	*((int *) data) = !!val;
+
+	if (old_val == val)
+		return 0;
+	if (val)
+		kmemtrace_start_probes();
+	else
+		kmemtrace_stop_probes();
+
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(kmemtrace_enabled_fops,
+			kmemtrace_enabled_get,
+			kmemtrace_enabled_set, "%llu\n");
+
+static void kmemtrace_cleanup(void)
+{
+	if (kmemtrace_enabled_dentry)
+		debugfs_remove(kmemtrace_enabled_dentry);
+
+	kmemtrace_stop_probes();
+
+	if (kmemtrace_abi_version_dentry)
+		debugfs_remove(kmemtrace_abi_version_dentry);
+	if (kmemtrace_overruns_dentry)
+		debugfs_remove(kmemtrace_overruns_dentry);
+
+	relay_close(kmemtrace_chan);
+	kmemtrace_chan = NULL;
+
+	if (kmemtrace_dir)
+		debugfs_remove(kmemtrace_dir);
+}
+
+static int __init kmemtrace_setup_late(void)
+{
+	if (!kmemtrace_chan)
+		goto failed;
+
+	kmemtrace_dir = debugfs_create_dir("kmemtrace", NULL);
+	if (!kmemtrace_dir)
+		goto cleanup;
+
+	kmemtrace_abi_version_dentry =
+		debugfs_create_u32("abi_version", S_IRUSR,
+				   kmemtrace_dir, &kmemtrace_abi_version);
+	kmemtrace_overruns_dentry =
+		debugfs_create_u32("total_overruns", S_IRUSR,
+				   kmemtrace_dir, &kmemtrace_buf_overruns);
+	if (!kmemtrace_overruns_dentry || !kmemtrace_abi_version_dentry)
+		goto cleanup;
+
+	kmemtrace_enabled_dentry =
+		debugfs_create_file("enabled", S_IRUSR | S_IWUSR,
+				    kmemtrace_dir, &kmemtrace_enabled,
+				    &kmemtrace_enabled_fops);
+	if (!kmemtrace_enabled_dentry)
+		goto cleanup;
+
+	if (relay_late_setup_files(kmemtrace_chan, "cpu", kmemtrace_dir))
+		goto cleanup;
+
+	printk(KERN_INFO "kmemtrace: fully up.\n");
+
+	return 0;
+
+cleanup:
+	kmemtrace_cleanup();
+failed:
+	return 1;
+}
+late_initcall(kmemtrace_setup_late);
+
+static int __init kmemtrace_set_boot_enabled(char *str)
+{
+	if (!str)
+		return -EINVAL;
+
+	if (!strcmp(str, "yes"))
+		kmemtrace_enabled = 1;
+	else if (!strcmp(str, "no"))
+		kmemtrace_enabled = 0;
+	else
+		return -EINVAL;
+
+	return 0;
+}
+early_param("kmemtrace.enable", kmemtrace_set_boot_enabled);
+
+static int __init kmemtrace_set_subbufs(char *str)
+{
+	get_option(&str, &kmemtrace_n_subbufs);
+	return 0;
+}
+early_param("kmemtrace.subbufs", kmemtrace_set_subbufs);
+
+void kmemtrace_init(void)
+{
+	if (!kmemtrace_n_subbufs)
+		kmemtrace_n_subbufs = KMEMTRACE_DEF_N_SUBBUFS;
+
+	kmemtrace_chan = relay_open(NULL, NULL, KMEMTRACE_SUBBUF_SIZE,
+				    kmemtrace_n_subbufs, &relay_callbacks,
+				    NULL);
+	if (!kmemtrace_chan) {
+		printk(KERN_ERR "kmemtrace: could not open relay channel.\n");
+		return;
+	}
+
+	if (!kmemtrace_enabled) {
+		printk(KERN_INFO "kmemtrace: disabled. Pass "
+			"kemtrace.enable=yes as kernel parameter for "
+			"boot-time tracing.\n");
+		return;
+	}
+	if (kmemtrace_start_probes()) {
+		printk(KERN_ERR "kmemtrace: could not register marker probes!\n");
+		kmemtrace_cleanup();
+		return;
+	}
+
+	printk(KERN_INFO "kmemtrace: enabled.\n");
+}
+