linux_dsm_epyc7002/drivers/dma-buf/sync_debug.c
Chris Wilson 71ebc9a379 dma-buf/sync-file: Defer creation of sync_file->name
Constructing the name takes the majority of the time for allocating a
sync_file to wrap a fence, and the name is very rarely used (only via
the sync_file status user interface). To reduce the impact on the common
path (that of creating sync_file to pass around), defer the construction
of the name until it is first used.

v2: Update kerneldoc (kbuild test robot)
v3: sync_debug.c was peeking at the name
v4: Comment upon the potential race between two users of
sync_file_get_name() and claim that such a race is below the level of
notice. However, to prevent any future nuisance, use a global spinlock
to serialize the assignment of the name.
v5: Completely avoid the read/write race by only storing the name passed
in from the user inside sync_file->user_name and passing in a buffer to
dynamically construct the name otherwise.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Herrmann <dh.herrmann@gmail.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170516111042.24719-1-chris@chris-wilson.co.uk
2017-05-24 13:08:29 -03:00

239 lines
5.9 KiB
C

/*
* Sync File validation framework and debug information
*
* Copyright (C) 2012 Google, Inc.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* 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.
*
*/
#include <linux/debugfs.h>
#include "sync_debug.h"
static struct dentry *dbgfs;
static LIST_HEAD(sync_timeline_list_head);
static DEFINE_SPINLOCK(sync_timeline_list_lock);
static LIST_HEAD(sync_file_list_head);
static DEFINE_SPINLOCK(sync_file_list_lock);
void sync_timeline_debug_add(struct sync_timeline *obj)
{
unsigned long flags;
spin_lock_irqsave(&sync_timeline_list_lock, flags);
list_add_tail(&obj->sync_timeline_list, &sync_timeline_list_head);
spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
}
void sync_timeline_debug_remove(struct sync_timeline *obj)
{
unsigned long flags;
spin_lock_irqsave(&sync_timeline_list_lock, flags);
list_del(&obj->sync_timeline_list);
spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
}
void sync_file_debug_add(struct sync_file *sync_file)
{
unsigned long flags;
spin_lock_irqsave(&sync_file_list_lock, flags);
list_add_tail(&sync_file->sync_file_list, &sync_file_list_head);
spin_unlock_irqrestore(&sync_file_list_lock, flags);
}
void sync_file_debug_remove(struct sync_file *sync_file)
{
unsigned long flags;
spin_lock_irqsave(&sync_file_list_lock, flags);
list_del(&sync_file->sync_file_list);
spin_unlock_irqrestore(&sync_file_list_lock, flags);
}
static const char *sync_status_str(int status)
{
if (status < 0)
return "error";
if (status > 0)
return "signaled";
return "active";
}
static void sync_print_fence(struct seq_file *s,
struct dma_fence *fence, bool show)
{
struct sync_timeline *parent = dma_fence_parent(fence);
int status;
status = dma_fence_get_status_locked(fence);
seq_printf(s, " %s%sfence %s",
show ? parent->name : "",
show ? "_" : "",
sync_status_str(status));
if (status) {
struct timespec64 ts64 =
ktime_to_timespec64(fence->timestamp);
seq_printf(s, "@%lld.%09ld", (s64)ts64.tv_sec, ts64.tv_nsec);
}
if (fence->ops->timeline_value_str &&
fence->ops->fence_value_str) {
char value[64];
bool success;
fence->ops->fence_value_str(fence, value, sizeof(value));
success = strlen(value);
if (success) {
seq_printf(s, ": %s", value);
fence->ops->timeline_value_str(fence, value,
sizeof(value));
if (strlen(value))
seq_printf(s, " / %s", value);
}
}
seq_putc(s, '\n');
}
static void sync_print_obj(struct seq_file *s, struct sync_timeline *obj)
{
struct list_head *pos;
unsigned long flags;
seq_printf(s, "%s: %d\n", obj->name, obj->value);
spin_lock_irqsave(&obj->child_list_lock, flags);
list_for_each(pos, &obj->child_list_head) {
struct sync_pt *pt =
container_of(pos, struct sync_pt, child_list);
sync_print_fence(s, &pt->base, false);
}
spin_unlock_irqrestore(&obj->child_list_lock, flags);
}
static void sync_print_sync_file(struct seq_file *s,
struct sync_file *sync_file)
{
char buf[128];
int i;
seq_printf(s, "[%p] %s: %s\n", sync_file,
sync_file_get_name(sync_file, buf, sizeof(buf)),
sync_status_str(dma_fence_get_status(sync_file->fence)));
if (dma_fence_is_array(sync_file->fence)) {
struct dma_fence_array *array = to_dma_fence_array(sync_file->fence);
for (i = 0; i < array->num_fences; ++i)
sync_print_fence(s, array->fences[i], true);
} else {
sync_print_fence(s, sync_file->fence, true);
}
}
static int sync_debugfs_show(struct seq_file *s, void *unused)
{
unsigned long flags;
struct list_head *pos;
seq_puts(s, "objs:\n--------------\n");
spin_lock_irqsave(&sync_timeline_list_lock, flags);
list_for_each(pos, &sync_timeline_list_head) {
struct sync_timeline *obj =
container_of(pos, struct sync_timeline,
sync_timeline_list);
sync_print_obj(s, obj);
seq_putc(s, '\n');
}
spin_unlock_irqrestore(&sync_timeline_list_lock, flags);
seq_puts(s, "fences:\n--------------\n");
spin_lock_irqsave(&sync_file_list_lock, flags);
list_for_each(pos, &sync_file_list_head) {
struct sync_file *sync_file =
container_of(pos, struct sync_file, sync_file_list);
sync_print_sync_file(s, sync_file);
seq_putc(s, '\n');
}
spin_unlock_irqrestore(&sync_file_list_lock, flags);
return 0;
}
static int sync_info_debugfs_open(struct inode *inode, struct file *file)
{
return single_open(file, sync_debugfs_show, inode->i_private);
}
static const struct file_operations sync_info_debugfs_fops = {
.open = sync_info_debugfs_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
};
static __init int sync_debugfs_init(void)
{
dbgfs = debugfs_create_dir("sync", NULL);
/*
* The debugfs files won't ever get removed and thus, there is
* no need to protect it against removal races. The use of
* debugfs_create_file_unsafe() is actually safe here.
*/
debugfs_create_file_unsafe("info", 0444, dbgfs, NULL,
&sync_info_debugfs_fops);
debugfs_create_file_unsafe("sw_sync", 0644, dbgfs, NULL,
&sw_sync_debugfs_fops);
return 0;
}
late_initcall(sync_debugfs_init);
#define DUMP_CHUNK 256
static char sync_dump_buf[64 * 1024];
void sync_dump(void)
{
struct seq_file s = {
.buf = sync_dump_buf,
.size = sizeof(sync_dump_buf) - 1,
};
int i;
sync_debugfs_show(&s, NULL);
for (i = 0; i < s.count; i += DUMP_CHUNK) {
if ((s.count - i) > DUMP_CHUNK) {
char c = s.buf[i + DUMP_CHUNK];
s.buf[i + DUMP_CHUNK] = 0;
pr_cont("%s", s.buf + i);
s.buf[i + DUMP_CHUNK] = c;
} else {
s.buf[s.count] = 0;
pr_cont("%s", s.buf + i);
}
}
}