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Fix race condition in Gravity.cpp

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iczero authored and LBPHacker committed Apr 7, 2019
1 parent ff39c82 commit 2ba0f70efdbdf9a33f077a5c7da204c584ad5d5b
Showing with 51 additions and 49 deletions.
  1. +1 −0 .gitignore
  2. +50 −49 src/simulation/Gravity.cpp
@@ -65,5 +65,6 @@ config.log
*.pyc
site_scons/site_tools/mfprogram/*.pyc
site_scons/site_tools/gch/*.pyc
.vscode/ipch

screenshot_*
@@ -83,47 +83,49 @@ void Gravity::gravity_cleanup()
void Gravity::gravity_update_async()
{
int result;
if(ngrav_enable)
if (ngrav_enable)
{
pthread_mutex_lock(&gravmutex);
result = grav_ready;
if(result) //Did the gravity thread finish?
if (!pthread_mutex_trylock(&gravmutex))
{
//if (!sys_pause||framerender){ //Only update if not paused
//Switch the full size gravmaps, we don't really need the two above any more
float *tmpf;

if (th_gravchanged && !ignoreNextResult)
{
#if !defined(GRAVFFT) && defined(GRAV_DIFF)
memcpy(gravy, th_gravy, (XRES/CELL)*(YRES/CELL)*sizeof(float));
memcpy(gravx, th_gravx, (XRES/CELL)*(YRES/CELL)*sizeof(float));
memcpy(gravp, th_gravp, (XRES/CELL)*(YRES/CELL)*sizeof(float));
#else
tmpf = gravy;
gravy = th_gravy;
th_gravy = tmpf;

tmpf = gravx;
gravx = th_gravx;
th_gravx = tmpf;

tmpf = gravp;
gravp = th_gravp;
th_gravp = tmpf;
#endif
}
ignoreNextResult = false;
result = grav_ready;
if (result) //Did the gravity thread finish?
{
//if (!sys_pause||framerender){ //Only update if not paused
//Switch the full size gravmaps, we don't really need the two above any more
float *tmpf;

if (th_gravchanged && !ignoreNextResult)
{
#if !defined(GRAVFFT) && defined(GRAV_DIFF)
memcpy(gravy, th_gravy, (XRES/CELL)*(YRES/CELL)*sizeof(float));
memcpy(gravx, th_gravx, (XRES/CELL)*(YRES/CELL)*sizeof(float));
memcpy(gravp, th_gravp, (XRES/CELL)*(YRES/CELL)*sizeof(float));
#else
tmpf = gravy;
gravy = th_gravy;
th_gravy = tmpf;

tmpf = gravx;
gravx = th_gravx;
th_gravx = tmpf;

tmpf = gravp;
gravp = th_gravp;
th_gravp = tmpf;
#endif
}
ignoreNextResult = false;

tmpf = gravmap;
gravmap = th_gravmap;
th_gravmap = tmpf;
tmpf = gravmap;
gravmap = th_gravmap;
th_gravmap = tmpf;

grav_ready = 0; //Tell the other thread that we're ready for it to continue
pthread_cond_signal(&gravcv);
//}
grav_ready = 0; //Tell the other thread that we're ready for it to continue
pthread_cond_signal(&gravcv);
//}
}
pthread_mutex_unlock(&gravmutex);
}
pthread_mutex_unlock(&gravmutex);
//Apply the gravity mask
membwand(gravy, gravmask, (XRES/CELL)*(YRES/CELL)*sizeof(float), (XRES/CELL)*(YRES/CELL)*sizeof(unsigned));
membwand(gravx, gravmask, (XRES/CELL)*(YRES/CELL)*sizeof(float), (XRES/CELL)*(YRES/CELL)*sizeof(unsigned));
@@ -153,32 +155,30 @@ void Gravity::update_grav_async()
if (!grav_fft_status)
grav_fft_init();
#endif
while(!thread_done){
if(!done){
pthread_mutex_lock(&gravmutex);
while (!thread_done)
{
if (!done)
{
// run gravity update
update_grav();
done = 1;
pthread_mutex_lock(&gravmutex);

grav_ready = done;
grav_ready = 1;
thread_done = gravthread_done;

pthread_mutex_unlock(&gravmutex);
} else {
pthread_mutex_lock(&gravmutex);
// wait for main thread
pthread_cond_wait(&gravcv, &gravmutex);

done = grav_ready;
thread_done = gravthread_done;

pthread_mutex_unlock(&gravmutex);
}
}
pthread_mutex_unlock(&gravmutex);
pthread_exit(NULL);
}

void Gravity::start_grav_async()
{
if(ngrav_enable) //If it's already enabled, restart it
if (ngrav_enable) //If it's already enabled, restart it
stop_grav_async();

gravthread_done = 0;
@@ -196,7 +196,8 @@ void Gravity::start_grav_async()

void Gravity::stop_grav_async()
{
if(ngrav_enable){
if (ngrav_enable)
{
pthread_mutex_lock(&gravmutex);
gravthread_done = 1;
pthread_cond_signal(&gravcv);

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