[FFmpeg-cvslog] vp8: make wait/thread_mb_pos atomic.
Ronald S. Bultje
git at videolan.org
Thu Apr 13 03:31:46 EEST 2017
ffmpeg | branch: release/3.3 | Ronald S. Bultje <rsbultje at gmail.com> | Wed Apr 5 16:18:54 2017 -0400| [9d742f774a85fa82cbfd667f69b0ba4d14556d54] | committer: Michael Niedermayer
vp8: make wait/thread_mb_pos atomic.
Fixes tsan warnings like this in fate-vp8-test-vector-007:
WARNING: ThreadSanitizer: data race (pid=3590)
Write of size 4 at 0x7d8c0000e07c by thread T2:
#0 decode_mb_row_no_filter src/libavcodec/vp8.c:2330 (ffmpeg+0x000000ffb59e)
[..]
Previous write of size 4 at 0x7d8c0000e07c by thread T1:
#0 decode_mb_row_no_filter src/libavcodec/vp8.c:2330 (ffmpeg+0x000000ffb59e)
(cherry picked from commit 9a54c6f243412f62bae498ddcac337cb18ae6290)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=9d742f774a85fa82cbfd667f69b0ba4d14556d54
---
libavcodec/vp8.c | 29 ++++++++++++++---------------
libavcodec/vp8.h | 6 ++++--
2 files changed, 18 insertions(+), 17 deletions(-)
diff --git a/libavcodec/vp8.c b/libavcodec/vp8.c
index 1e8808c46f..9bc1d95220 100644
--- a/libavcodec/vp8.c
+++ b/libavcodec/vp8.c
@@ -2247,15 +2247,15 @@ static void vp8_decode_mv_mb_modes(AVCodecContext *avctx, VP8Frame *cur_frame,
#define check_thread_pos(td, otd, mb_x_check, mb_y_check) \
do { \
int tmp = (mb_y_check << 16) | (mb_x_check & 0xFFFF); \
- if (otd->thread_mb_pos < tmp) { \
+ if (atomic_load(&otd->thread_mb_pos) < tmp) { \
pthread_mutex_lock(&otd->lock); \
- td->wait_mb_pos = tmp; \
+ atomic_store(&td->wait_mb_pos, tmp); \
do { \
- if (otd->thread_mb_pos >= tmp) \
+ if (atomic_load(&otd->thread_mb_pos) >= tmp) \
break; \
pthread_cond_wait(&otd->cond, &otd->lock); \
} while (1); \
- td->wait_mb_pos = INT_MAX; \
+ atomic_store(&td->wait_mb_pos, INT_MAX); \
pthread_mutex_unlock(&otd->lock); \
} \
} while (0)
@@ -2266,12 +2266,10 @@ static void vp8_decode_mv_mb_modes(AVCodecContext *avctx, VP8Frame *cur_frame,
int sliced_threading = (avctx->active_thread_type == FF_THREAD_SLICE) && \
(num_jobs > 1); \
int is_null = !next_td || !prev_td; \
- int pos_check = (is_null) ? 1 \
- : (next_td != td && \
- pos >= next_td->wait_mb_pos) || \
- (prev_td != td && \
- pos >= prev_td->wait_mb_pos); \
- td->thread_mb_pos = pos; \
+ int pos_check = (is_null) ? 1 : \
+ (next_td != td && pos >= atomic_load(&next_td->wait_mb_pos)) || \
+ (prev_td != td && pos >= atomic_load(&prev_td->wait_mb_pos)); \
+ atomic_store(&td->thread_mb_pos, pos); \
if (sliced_threading && pos_check) { \
pthread_mutex_lock(&td->lock); \
pthread_cond_broadcast(&td->cond); \
@@ -2288,7 +2286,7 @@ static av_always_inline int decode_mb_row_no_filter(AVCodecContext *avctx, void
{
VP8Context *s = avctx->priv_data;
VP8ThreadData *prev_td, *next_td, *td = &s->thread_data[threadnr];
- int mb_y = td->thread_mb_pos >> 16;
+ int mb_y = atomic_load(&td->thread_mb_pos) >> 16;
int mb_x, mb_xy = mb_y * s->mb_width;
int num_jobs = s->num_jobs;
VP8Frame *curframe = s->curframe, *prev_frame = s->prev_frame;
@@ -2428,7 +2426,7 @@ static av_always_inline void filter_mb_row(AVCodecContext *avctx, void *tdata,
{
VP8Context *s = avctx->priv_data;
VP8ThreadData *td = &s->thread_data[threadnr];
- int mb_x, mb_y = td->thread_mb_pos >> 16, num_jobs = s->num_jobs;
+ int mb_x, mb_y = atomic_load(&td->thread_mb_pos) >> 16, num_jobs = s->num_jobs;
AVFrame *curframe = s->curframe->tf.f;
VP8Macroblock *mb;
VP8ThreadData *prev_td, *next_td;
@@ -2507,7 +2505,7 @@ int vp78_decode_mb_row_sliced(AVCodecContext *avctx, void *tdata, int jobnr,
td->thread_nr = threadnr;
for (mb_y = jobnr; mb_y < s->mb_height; mb_y += num_jobs) {
- td->thread_mb_pos = mb_y << 16;
+ atomic_store(&td->thread_mb_pos, mb_y << 16);
ret = s->decode_mb_row_no_filter(avctx, tdata, jobnr, threadnr);
if (ret < 0) {
update_pos(td, s->mb_height, INT_MAX & 0xFFFF);
@@ -2667,8 +2665,9 @@ int vp78_decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
s->mv_min.y = -MARGIN;
s->mv_max.y = ((s->mb_height - 1) << 6) + MARGIN;
for (i = 0; i < MAX_THREADS; i++) {
- s->thread_data[i].thread_mb_pos = 0;
- s->thread_data[i].wait_mb_pos = INT_MAX;
+ VP8ThreadData *td = &s->thread_data[i];
+ atomic_init(&td->thread_mb_pos, 0);
+ atomic_init(&td->wait_mb_pos, INT_MAX);
}
if (is_vp7)
avctx->execute2(avctx, vp7_decode_mb_row_sliced, s->thread_data, NULL,
diff --git a/libavcodec/vp8.h b/libavcodec/vp8.h
index 3910b5c0dd..d7e7680276 100644
--- a/libavcodec/vp8.h
+++ b/libavcodec/vp8.h
@@ -26,6 +26,8 @@
#ifndef AVCODEC_VP8_H
#define AVCODEC_VP8_H
+#include <stdatomic.h>
+
#include "libavutil/buffer.h"
#include "libavutil/thread.h"
@@ -114,8 +116,8 @@ typedef struct VP8ThreadData {
pthread_mutex_t lock;
pthread_cond_t cond;
#endif
- int thread_mb_pos; // (mb_y << 16) | (mb_x & 0xFFFF)
- int wait_mb_pos; // What the current thread is waiting on.
+ atomic_int thread_mb_pos; // (mb_y << 16) | (mb_x & 0xFFFF)
+ atomic_int wait_mb_pos; // What the current thread is waiting on.
#define EDGE_EMU_LINESIZE 32
DECLARE_ALIGNED(16, uint8_t, edge_emu_buffer)[21 * EDGE_EMU_LINESIZE];
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