diff options
Diffstat (limited to 'mm/kmemtrace.c')
| -rw-r--r-- | mm/kmemtrace.c | 333 |
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"); +} + |