Schedule one job for every thread, and wait on a barrier inside the job
execution function.
v2: avoid alloca (fixes Windows build error)
Reviewed-by: Marek Olšák <marek.olsak@amd.com> (v1)
Fences are now 4 bytes instead of 96 bytes (on my 64-bit system).
Signaling a fence is a single atomic operation in the fast case plus a
syscall in the slow case.
Testing if a fence is signaled is the same as before (a simple comparison),
but waiting on a fence is now no more expensive than just testing it in
the fast (already signaled) case.
v2:
- style fixes
- use p_atomic_xxx macros with the right barriers
Acked-by: Marek Olšák <marek.olsak@amd.com>
A tempting alternative fix would be adding a lock/unlock pair in
util_queue_fence_is_signalled. However, that wouldn't actually
improve anything in the semantics of util_queue_fence_is_signalled,
while making that test much more heavy-weight. So this lock/unlock
pair in util_queue_fence_destroy for "flushing out" other threads
that may still be in util_queue_fence_signal looks like the better
fix.
v2: rephrase the comment
Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Gustaw Smolarczyk <wielkiegie@gmail.com>
Consider the following situation:
mtx_lock(mutex);
do_something();
util_queue_add_job(...);
mtx_unlock(mutex);
If the queue is full, util_queue_add_job will wait for a free slot.
If the job which is currently being executed tries to lock the mutex,
it will be stuck forever, because util_queue_add_job is stuck.
The deadlock can be trivially resolved by increasing the queue size
(reallocating the queue) in util_queue_add_job if the queue is full.
Then util_queue_add_job becomes wait-free.
radeonsi will use it.
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
So atexit() is horrible and 4aea8fe7 is probably not a good idea. But
add an extra layer of duct-tape to the problem. Otherwise we hit a
situation where app using an atexit() handler that runs later than ours
doesn't hang when trying to tear down a context.
(gdb) bt
#0 util_queue_killall_and_wait (queue=queue@entry=0x52bc80) at ../../../src/util/u_queue.c:264
#1 0x0000007fb6c380c0 in atexit_handler () at ../../../src/util/u_queue.c:51
#2 0x0000007fb7730e2c in __run_exit_handlers () from /lib64/libc.so.6
#3 0x0000007fb7730e5c in exit () from /lib64/libc.so.6
#4 0x0000007fb7ce17dc in piglit_report_result (result=PIGLIT_PASS) at /home/robclark/src/piglit/tests/util/piglit-util.c:267
#5 0x0000007fb7ef99f8 in process_next_event (x11_fw=0x432c20) at /home/robclark/src/piglit/tests/util/piglit-framework-gl/piglit_x11_framework.c:139
#6 0x0000007fb7ef9a90 in enter_event_loop (winsys_fw=0x432c20) at /home/robclark/src/piglit/tests/util/piglit-framework-gl/piglit_x11_framework.c:153
#7 0x0000007fb7ef8e50 in run_test (gl_fw=0x432c20, argc=1, argv=0x7ffffff588) at /home/robclark/src/piglit/tests/util/piglit-framework-gl/piglit_winsys_framework.c:88
#8 0x0000007fb7edb890 in piglit_gl_test_run (argc=1, argv=0x7ffffff588, config=0x7ffffff400) at /home/robclark/src/piglit/tests/util/piglit-framework-gl.c:203
#9 0x0000000000401224 in main (argc=1, argv=0x7ffffff588) at /home/robclark/src/piglit/tests/bugs/drawbuffer-modes.c:46
(gdb) c
Continuing.
[Thread 0x7fb67580c0 (LWP 3471) exited]
^C
Thread 1 "drawbuffer-mode" received signal SIGINT, Interrupt.
0x0000007fb72dda34 in pthread_cond_wait@@GLIBC_2.17 () from /lib64/libpthread.so.0
(gdb) bt
#0 0x0000007fb72dda34 in pthread_cond_wait@@GLIBC_2.17 () from /lib64/libpthread.so.0
#1 0x0000007fb6c38304 in cnd_wait (mtx=0x5bdc90, cond=0x5bdcc0) at ../../../include/c11/threads_posix.h:159
#2 util_queue_fence_wait (fence=0x5bdc90) at ../../../src/util/u_queue.c:106
#3 0x0000007fb6daac70 in fd_batch_sync (batch=0x5bdc70) at ../../../../../src/gallium/drivers/freedreno/freedreno_batch.c:233
#4 batch_reset (batch=batch@entry=0x5bdc70) at ../../../../../src/gallium/drivers/freedreno/freedreno_batch.c:183
#5 0x0000007fb6daa5e0 in batch_flush (batch=0x5bdc70) at ../../../../../src/gallium/drivers/freedreno/freedreno_batch.c:290
#6 fd_batch_flush (batch=0x5bdc70, sync=<optimized out>) at ../../../../../src/gallium/drivers/freedreno/freedreno_batch.c:308
#7 0x0000007fb6daba2c in fd_bc_flush (cache=0x461220, ctx=0x52b920) at ../../../../../src/gallium/drivers/freedreno/freedreno_batch_cache.c:141
#8 0x0000007fb6dac954 in fd_context_flush (pctx=0x52b920, fence=0x0, flags=<optimized out>) at ../../../../../src/gallium/drivers/freedreno/freedreno_context.c:54
#9 0x0000007fb6b43294 in st_glFlush (ctx=<optimized out>) at ../../../src/mesa/state_tracker/st_cb_flush.c:121
#10 0x0000007fb69a84e8 in _mesa_make_current (newCtx=newCtx@entry=0x0, drawBuffer=drawBuffer@entry=0x0, readBuffer=readBuffer@entry=0x0) at ../../../src/mesa/main/context.c:1654
#11 0x0000007fb6b7ca58 in st_api_make_current (stapi=<optimized out>, stctxi=0x0, stdrawi=0x0, streadi=0x0) at ../../../src/mesa/state_tracker/st_manager.c:827
#12 0x0000007fb6cc87e8 in dri_unbind_context (cPriv=<optimized out>) at ../../../../../src/gallium/state_trackers/dri/dri_context.c:217
#13 0x0000007fb6cc80b0 in driUnbindContext (pcp=0x5271e0) at ../../../../../../src/mesa/drivers/dri/common/dri_util.c:591
#14 0x0000007fb7d1da08 in MakeContextCurrent (dpy=0x433380, draw=0, read=0, gc_user=0x0) at ../../../src/glx/glxcurrent.c:214
#15 0x0000007fb7a8d5e0 in glx_platform_make_current () from /lib64/libwaffle-1.so.0
#16 0x0000007fb7a894e4 in waffle_make_current () from /lib64/libwaffle-1.so.0
#17 0x0000007fb7ef8c60 in piglit_wfl_framework_teardown (wfl_fw=0x432c20) at /home/robclark/src/piglit/tests/util/piglit-framework-gl/piglit_wfl_framework.c:628
#18 0x0000007fb7ef939c in piglit_winsys_framework_teardown (winsys_fw=0x432c20) at /home/robclark/src/piglit/tests/util/piglit-framework-gl/piglit_winsys_framework.c:238
#19 0x0000007fb7ef9c30 in destroy (gl_fw=0x432c20) at /home/robclark/src/piglit/tests/util/piglit-framework-gl/piglit_x11_framework.c:212
#20 0x0000007fb7edb7c4 in destroy () at /home/robclark/src/piglit/tests/util/piglit-framework-gl.c:184
#21 0x0000007fb7730e2c in __run_exit_handlers () from /lib64/libc.so.6
#22 0x0000007fb7730e5c in exit () from /lib64/libc.so.6
#23 0x0000007fb7ce17dc in piglit_report_result (result=PIGLIT_PASS) at /home/robclark/src/piglit/tests/util/piglit-util.c:267
#24 0x0000007fb7ef99f8 in process_next_event (x11_fw=0x432c20) at /home/robclark/src/piglit/tests/util/piglit-framework-gl/piglit_x11_framework.c:139
#25 0x0000007fb7ef9a90 in enter_event_loop (winsys_fw=0x432c20) at /home/robclark/src/piglit/tests/util/piglit-framework-gl/piglit_x11_framework.c:153
#26 0x0000007fb7ef8e50 in run_test (gl_fw=0x432c20, argc=1, argv=0x7ffffff588) at /home/robclark/src/piglit/tests/util/piglit-framework-gl/piglit_winsys_framework.c:88
#27 0x0000007fb7edb890 in piglit_gl_test_run (argc=1, argv=0x7ffffff588, config=0x7ffffff400) at /home/robclark/src/piglit/tests/util/piglit-framework-gl.c:203
#28 0x0000000000401224 in main (argc=1, argv=0x7ffffff588) at /home/robclark/src/piglit/tests/bugs/drawbuffer-modes.c:46
(gdb) r
Fixes: 4aea8fe7 ("gallium/u_queue: fix random crashes when the app calls exit()")
Signed-off-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
