Commit: dca32f2b4f290bcf8c110c21d2cdecc04d390934 Author: Alexander Gavrilov Date: Sat Oct 26 11:06:19 2019 +0300 Branches: master https://developer.blender.org/rBdca32f2b4f290bcf8c110c21d2cdecc04d390934
Fluid Particles: fix threading crash with viscoelastic springs. As correctly pointed out by a comment in the code, adding new springs wasn't thread safe, and caused crashes. Fix by buffering new springs in intermediate thread-local arrays, which are flushed on the main thread. This is valid because the new springs are not used until the next sim step. Differential Revision: https://developer.blender.org/D6133 =================================================================== M source/blender/blenkernel/BKE_particle.h M source/blender/blenkernel/intern/particle_system.c M source/blender/blenlib/BLI_buffer.h =================================================================== diff --git a/source/blender/blenkernel/BKE_particle.h b/source/blender/blenkernel/BKE_particle.h index e9b4c2b5a66..857ed607dd8 100644 --- a/source/blender/blenkernel/BKE_particle.h +++ b/source/blender/blenkernel/BKE_particle.h @@ -28,6 +28,7 @@ */ #include "BLI_utildefines.h" +#include "BLI_buffer.h" #include "DNA_particle_types.h" #include "DNA_object_types.h" @@ -108,6 +109,9 @@ typedef struct SPHData { float element_size; float flow[3]; + /* Temporary thread-local buffer for springs created during this step. */ + BLI_Buffer new_springs; + /* Integrator callbacks. This allows different SPH implementations. */ void (*force_cb)(void *sphdata_v, ParticleKey *state, float *force, float *impulse); void (*density_cb)(void *rangedata_v, int index, const float co[3], float squared_dist); diff --git a/source/blender/blenkernel/intern/particle_system.c b/source/blender/blenkernel/intern/particle_system.c index 43484a57f1c..5985d498606 100644 --- a/source/blender/blenkernel/intern/particle_system.c +++ b/source/blender/blenkernel/intern/particle_system.c @@ -1901,8 +1901,7 @@ static void sph_force_cb(void *sphdata_v, ParticleKey *state, float *force, floa temp_spring.rest_length = (fluid->flag & SPH_CURRENT_REST_LENGTH) ? rij : rest_length; temp_spring.delete_flag = 0; - /* sph_spring_add is not thread-safe. - z0r */ - sph_spring_add(psys[0], &temp_spring); + BLI_buffer_append(&sphdata->new_springs, ParticleSpring, temp_spring); } } else { /* PART_SPRING_HOOKES - Hooke's spring force */ @@ -2124,6 +2123,8 @@ void psys_sph_init(ParticleSimulationData *sim, SPHData *sphdata) ParticleTarget *pt; int i; + BLI_buffer_field_init(&sphdata->new_springs, ParticleSpring); + // Add other coupled particle systems. sphdata->psys[0] = sim->psys; for (i = 1, pt = sim->psys->targets.first; i < 10; i++, pt = (pt ? pt->next : NULL)) { @@ -2156,13 +2157,26 @@ void psys_sph_init(ParticleSimulationData *sim, SPHData *sphdata) } } +static void psys_sph_flush_springs(SPHData *sphdata) +{ + for (int i = 0; i < sphdata->new_springs.count; i++) { + /* sph_spring_add is not thread-safe. - z0r */ + sph_spring_add(sphdata->psys[0], &BLI_buffer_at(&sphdata->new_springs, ParticleSpring, i)); + } + + BLI_buffer_field_free(&sphdata->new_springs); +} + void psys_sph_finalise(SPHData *sphdata) { + psys_sph_flush_springs(sphdata); + if (sphdata->eh) { BLI_edgehash_free(sphdata->eh, NULL); sphdata->eh = NULL; } } + /* Sample the density field at a point in space. */ void psys_sph_density(BVHTree *tree, SPHData *sphdata, float co[3], float vars[2]) { @@ -3683,6 +3697,14 @@ typedef struct DynamicStepSolverTaskData { SpinLock spin; } DynamicStepSolverTaskData; +static void dynamics_step_finalize_sphdata(void *__restrict UNUSED(userdata), + void *__restrict tls_userdata_chunk) +{ + SPHData *sphdata = tls_userdata_chunk; + + psys_sph_flush_springs(sphdata); +} + static void dynamics_step_sph_ddr_task_cb_ex(void *__restrict userdata, const int p, const TaskParallelTLS *__restrict tls) @@ -3969,6 +3991,7 @@ static void dynamics_step(ParticleSimulationData *sim, float cfra) settings.use_threading = (psys->totpart > 100); settings.userdata_chunk = &sphdata; settings.userdata_chunk_size = sizeof(sphdata); + settings.func_finalize = dynamics_step_finalize_sphdata; BLI_task_parallel_range( 0, psys->totpart, &task_data, dynamics_step_sph_ddr_task_cb_ex, &settings); @@ -4000,6 +4023,7 @@ static void dynamics_step(ParticleSimulationData *sim, float cfra) settings.use_threading = (psys->totpart > 100); settings.userdata_chunk = &sphdata; settings.userdata_chunk_size = sizeof(sphdata); + settings.func_finalize = dynamics_step_finalize_sphdata; BLI_task_parallel_range(0, psys->totpart, &task_data, @@ -4014,6 +4038,7 @@ static void dynamics_step(ParticleSimulationData *sim, float cfra) settings.use_threading = (psys->totpart > 100); settings.userdata_chunk = &sphdata; settings.userdata_chunk_size = sizeof(sphdata); + settings.func_finalize = dynamics_step_finalize_sphdata; BLI_task_parallel_range(0, psys->totpart, &task_data, diff --git a/source/blender/blenlib/BLI_buffer.h b/source/blender/blenlib/BLI_buffer.h index 6fe1e9bb693..22d21262712 100644 --- a/source/blender/blenlib/BLI_buffer.h +++ b/source/blender/blenlib/BLI_buffer.h @@ -83,4 +83,14 @@ void _bli_buffer_free(BLI_Buffer *buffer); } \ (void)0 +/* A buffer embedded in a struct. Using memcpy is allowed until first resize. */ +#define BLI_buffer_field_init(name_, type_) \ + { \ + memset(name_, 0, sizeof(*name_)); \ + *(size_t *)&((name_)->elem_size) = sizeof(type_); \ + } \ + (void)0 + +#define BLI_buffer_field_free(name_) _bli_buffer_free(name_) + #endif /* __BLI_BUFFER_H__ */ _______________________________________________ Bf-blender-cvs mailing list Bf-blender-cvs@blender.org https://lists.blender.org/mailman/listinfo/bf-blender-cvs