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dm vdo: add debugging support

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Add support for dumping detailed vdo state to the kernel log via a dmsetup
message. The dump code is not thread-safe and is generally intended for use
only when the vdo is hung.

Co-developed-by: J. corwin Coburn <corwin@hurlbutnet.net>
Signed-off-by: J. corwin Coburn <corwin@hurlbutnet.net>
Co-developed-by: Michael Sclafani <dm-devel@lists.linux.dev>
Signed-off-by: Michael Sclafani <dm-devel@lists.linux.dev>
Co-developed-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Co-developed-by: Bruce Johnston <bjohnsto@redhat.com>
Signed-off-by: Bruce Johnston <bjohnsto@redhat.com>
Co-developed-by: Ken Raeburn <raeburn@redhat.com>
Signed-off-by: Ken Raeburn <raeburn@redhat.com>
Signed-off-by: Matthew Sakai <msakai@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
This commit is contained in:
Matthew Sakai 2023-11-16 21:12:14 -05:00 committed by Mike Snitzer
parent 92f8d7a94f
commit 29a811959c
2 changed files with 295 additions and 0 deletions
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278
drivers/md/dm-vdo/dump.c Normal file
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright 2023 Red Hat
*/
#include "dump.h"
#include <linux/module.h>
#include "memory-alloc.h"
#include "string-utils.h"
#include "constants.h"
#include "data-vio.h"
#include "dedupe.h"
#include "funnel-workqueue.h"
#include "io-submitter.h"
#include "logger.h"
#include "types.h"
#include "vdo.h"
enum dump_options {
/* Work queues */
SHOW_QUEUES,
/* Memory pools */
SHOW_VIO_POOL,
/* Others */
SHOW_VDO_STATUS,
/* This one means an option overrides the "default" choices, instead of altering them. */
SKIP_DEFAULT
};
enum dump_option_flags {
/* Work queues */
FLAG_SHOW_QUEUES = (1 << SHOW_QUEUES),
/* Memory pools */
FLAG_SHOW_VIO_POOL = (1 << SHOW_VIO_POOL),
/* Others */
FLAG_SHOW_VDO_STATUS = (1 << SHOW_VDO_STATUS),
/* Special */
FLAG_SKIP_DEFAULT = (1 << SKIP_DEFAULT)
};
enum {
FLAGS_ALL_POOLS = (FLAG_SHOW_VIO_POOL),
DEFAULT_DUMP_FLAGS = (FLAG_SHOW_QUEUES | FLAG_SHOW_VDO_STATUS)
};
static inline bool is_arg_string(const char *arg, const char *this_option)
{
/* convention seems to be case-independent options */
return strncasecmp(arg, this_option, strlen(this_option)) == 0;
}
static void do_dump(struct vdo *vdo, unsigned int dump_options_requested,
const char *why)
{
u32 active, maximum;
s64 outstanding;
uds_log_info("%s dump triggered via %s", UDS_LOGGING_MODULE_NAME, why);
active = get_data_vio_pool_active_requests(vdo->data_vio_pool);
maximum = get_data_vio_pool_maximum_requests(vdo->data_vio_pool);
outstanding = (atomic64_read(&vdo->stats.bios_submitted) -
atomic64_read(&vdo->stats.bios_completed));
uds_log_info("%u device requests outstanding (max %u), %lld bio requests outstanding, device '%s'",
active, maximum, outstanding,
vdo_get_device_name(vdo->device_config->owning_target));
if (((dump_options_requested & FLAG_SHOW_QUEUES) != 0) && (vdo->threads != NULL)) {
thread_id_t id;
for (id = 0; id < vdo->thread_config.thread_count; id++)
vdo_dump_work_queue(vdo->threads[id].queue);
}
vdo_dump_hash_zones(vdo->hash_zones);
dump_data_vio_pool(vdo->data_vio_pool,
(dump_options_requested & FLAG_SHOW_VIO_POOL) != 0);
if ((dump_options_requested & FLAG_SHOW_VDO_STATUS) != 0)
vdo_dump_status(vdo);
uds_report_memory_usage();
uds_log_info("end of %s dump", UDS_LOGGING_MODULE_NAME);
}
static int parse_dump_options(unsigned int argc, char *const *argv,
unsigned int *dump_options_requested_ptr)
{
unsigned int dump_options_requested = 0;
static const struct {
const char *name;
unsigned int flags;
} option_names[] = {
{ "viopool", FLAG_SKIP_DEFAULT | FLAG_SHOW_VIO_POOL },
{ "vdo", FLAG_SKIP_DEFAULT | FLAG_SHOW_VDO_STATUS },
{ "pools", FLAG_SKIP_DEFAULT | FLAGS_ALL_POOLS },
{ "queues", FLAG_SKIP_DEFAULT | FLAG_SHOW_QUEUES },
{ "threads", FLAG_SKIP_DEFAULT | FLAG_SHOW_QUEUES },
{ "default", FLAG_SKIP_DEFAULT | DEFAULT_DUMP_FLAGS },
{ "all", ~0 },
};
bool options_okay = true;
unsigned int i;
for (i = 1; i < argc; i++) {
unsigned int j;
for (j = 0; j < ARRAY_SIZE(option_names); j++) {
if (is_arg_string(argv[i], option_names[j].name)) {
dump_options_requested |= option_names[j].flags;
break;
}
}
if (j == ARRAY_SIZE(option_names)) {
uds_log_warning("dump option name '%s' unknown", argv[i]);
options_okay = false;
}
}
if (!options_okay)
return -EINVAL;
if ((dump_options_requested & FLAG_SKIP_DEFAULT) == 0)
dump_options_requested |= DEFAULT_DUMP_FLAGS;
*dump_options_requested_ptr = dump_options_requested;
return 0;
}
/* Dump as specified by zero or more string arguments. */
int vdo_dump(struct vdo *vdo, unsigned int argc, char *const *argv, const char *why)
{
unsigned int dump_options_requested = 0;
int result = parse_dump_options(argc, argv, &dump_options_requested);
if (result != 0)
return result;
do_dump(vdo, dump_options_requested, why);
return 0;
}
/* Dump everything we know how to dump */
void vdo_dump_all(struct vdo *vdo, const char *why)
{
do_dump(vdo, ~0, why);
}
/*
* Dump out the data_vio waiters on a wait queue.
* wait_on should be the label to print for queue (e.g. logical or physical)
*/
static void dump_vio_waiters(struct wait_queue *queue, char *wait_on)
{
struct waiter *waiter, *first = vdo_get_first_waiter(queue);
struct data_vio *data_vio;
if (first == NULL)
return;
data_vio = waiter_as_data_vio(first);
uds_log_info(" %s is locked. Waited on by: vio %px pbn %llu lbn %llu d-pbn %llu lastOp %s",
wait_on, data_vio, data_vio->allocation.pbn, data_vio->logical.lbn,
data_vio->duplicate.pbn, get_data_vio_operation_name(data_vio));
for (waiter = first->next_waiter; waiter != first; waiter = waiter->next_waiter) {
data_vio = waiter_as_data_vio(waiter);
uds_log_info(" ... and : vio %px pbn %llu lbn %llu d-pbn %llu lastOp %s",
data_vio, data_vio->allocation.pbn, data_vio->logical.lbn,
data_vio->duplicate.pbn,
get_data_vio_operation_name(data_vio));
}
}
/*
* Encode various attributes of a data_vio as a string of one-character flags. This encoding is for
* logging brevity:
*
* R => vio completion result not VDO_SUCCESS
* W => vio is on a wait queue
* D => vio is a duplicate
* p => vio is a partial block operation
* z => vio is a zero block
* d => vio is a discard
*
* The common case of no flags set will result in an empty, null-terminated buffer. If any flags
* are encoded, the first character in the string will be a space character.
*/
static void encode_vio_dump_flags(struct data_vio *data_vio, char buffer[8])
{
char *p_flag = buffer;
*p_flag++ = ' ';
if (data_vio->vio.completion.result != VDO_SUCCESS)
*p_flag++ = 'R';
if (data_vio->waiter.next_waiter != NULL)
*p_flag++ = 'W';
if (data_vio->is_duplicate)
*p_flag++ = 'D';
if (data_vio->is_partial)
*p_flag++ = 'p';
if (data_vio->is_zero)
*p_flag++ = 'z';
if (data_vio->remaining_discard > 0)
*p_flag++ = 'd';
if (p_flag == &buffer[1]) {
/* No flags, so remove the blank space. */
p_flag = buffer;
}
*p_flag = '\0';
}
/* Implements buffer_dump_function. */
void dump_data_vio(void *data)
{
struct data_vio *data_vio = data;
/*
* This just needs to be big enough to hold a queue (thread) name and a function name (plus
* a separator character and NUL). The latter is limited only by taste.
*
* In making this static, we're assuming only one "dump" will run at a time. If more than
* one does run, the log output will be garbled anyway.
*/
static char vio_completion_dump_buffer[100 + MAX_VDO_WORK_QUEUE_NAME_LEN];
/* Another static buffer... log10(256) = 2.408+, round up: */
enum { DIGITS_PER_U64 = 1 + sizeof(u64) * 2409 / 1000 };
static char vio_block_number_dump_buffer[sizeof("P L D") + 3 * DIGITS_PER_U64];
static char vio_flush_generation_buffer[sizeof(" FG") + DIGITS_PER_U64];
static char flags_dump_buffer[8];
/*
* We're likely to be logging a couple thousand of these lines, and in some circumstances
* syslogd may have trouble keeping up, so keep it BRIEF rather than user-friendly.
*/
vdo_dump_completion_to_buffer(&data_vio->vio.completion,
vio_completion_dump_buffer,
sizeof(vio_completion_dump_buffer));
if (data_vio->is_duplicate) {
snprintf(vio_block_number_dump_buffer,
sizeof(vio_block_number_dump_buffer), "P%llu L%llu D%llu",
data_vio->allocation.pbn, data_vio->logical.lbn,
data_vio->duplicate.pbn);
} else if (data_vio_has_allocation(data_vio)) {
snprintf(vio_block_number_dump_buffer,
sizeof(vio_block_number_dump_buffer), "P%llu L%llu",
data_vio->allocation.pbn, data_vio->logical.lbn);
} else {
snprintf(vio_block_number_dump_buffer,
sizeof(vio_block_number_dump_buffer), "L%llu",
data_vio->logical.lbn);
}
if (data_vio->flush_generation != 0) {
snprintf(vio_flush_generation_buffer,
sizeof(vio_flush_generation_buffer), " FG%llu",
data_vio->flush_generation);
} else {
vio_flush_generation_buffer[0] = 0;
}
encode_vio_dump_flags(data_vio, flags_dump_buffer);
uds_log_info(" vio %px %s%s %s %s%s", data_vio,
vio_block_number_dump_buffer,
vio_flush_generation_buffer,
get_data_vio_operation_name(data_vio),
vio_completion_dump_buffer,
flags_dump_buffer);
/*
* might want info on: wantUDSAnswer / operation / status
* might want info on: bio / bios_merged
*/
dump_vio_waiters(&data_vio->logical.waiters, "lbn");
/* might want to dump more info from vio here */
}

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drivers/md/dm-vdo/dump.h Normal file
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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright 2023 Red Hat
*/
#ifndef VDO_DUMP_H
#define VDO_DUMP_H
#include "types.h"
int vdo_dump(struct vdo *vdo, unsigned int argc, char *const *argv, const char *why);
void vdo_dump_all(struct vdo *vdo, const char *why);
void dump_data_vio(void *data);
#endif /* VDO_DUMP_H */