2 files changed, 336 insertions, 0 deletions

diff --git a/mm/Makefile b/mm/Makefile
index c06b45a1ff5f..3782eb66d4b3 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -34,3 +34,4 @@ obj-$(CONFIG_MIGRATION) += migrate.o
 obj-$(CONFIG_SMP) += allocpercpu.o
 obj-$(CONFIG_QUICKLIST) += quicklist.o
 obj-$(CONFIG_CGROUP_MEM_RES_CTLR) += memcontrol.o page_cgroup.o
+obj-$(CONFIG_KMEMTRACE) += kmemtrace.o
diff --git a/mm/kmemtrace.c b/mm/kmemtrace.c
new file mode 100644
index 000000000000..83ad1cc71a92
--- /dev/null
+++ b/mm/kmemtrace.c
@@ -0,0 +1,335 @@
+/*
+ * 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;
+#ifdef CONFIG_KMEMTRACE_DEFAULT_ENABLED
+static unsigned int kmemtrace_enabled = 1;
+#else
+static unsigned int kmemtrace_enabled = 0;
+#endif
+
+/*
+ * 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_enabled)
+                return;
+
+        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 (unlikely(!kmemtrace_chan)) {
+                printk(KERN_ERR "kmemtrace: could not open relay channel.\n");
+                return;
+        }
+
+        if (unlikely(kmemtrace_start_probes()))
+                goto probe_fail;
+
+        printk(KERN_INFO "kmemtrace: early init successful.\n");
+
+        return;
+
+probe_fail:
+        printk(KERN_ERR "kmemtrace: could not register marker probes!\n");
+        kmemtrace_cleanup();
+}
+