parallelized raster modules: fix buffer sizes (#3070)

* parallelized raster modules: fix buffer sizes

* safety check for unsigned integer subtraction

raster/r.neighbors/main.c

@@ -148,7 +148,7 @@ int main(int argc, char *argv[])
     int *readrow;
     int nrows, ncols, brows;
     int i, n, t;
-    size_t size;
+    size_t size, in_buf_size, out_buf_size;
     struct Colors colr;
     struct Cell_head cellhd;
     struct Cell_head window;
@@ -338,15 +338,6 @@ int main(int argc, char *argv[])
 
     nrows = Rast_window_rows();
     ncols = Rast_window_cols();
-    brows = atoi(parm.memory->answer) * ((1 << 20) / sizeof(DCELL)) / ncols;
-    /* set the output buffer rows to be at most covering the entire map */
-    if (brows > nrows) {
-        brows = nrows;
-    }
-    /* but at least the number of threads */
-    if (brows < ncb.threads) {
-        brows = ncb.threads;
-    }
 
     /* open raster maps */
     in_fd = G_malloc(sizeof(int) * ncb.threads);
@@ -368,6 +359,27 @@ int main(int argc, char *argv[])
 
     outputs = G_calloc(num_outputs, sizeof(struct output));
 
+    /* memory reserved for input */
+    in_buf_size = (Rast_window_cols() + 2 * ncb.dist) * sizeof(DCELL) *
+                  ncb.nsize * ncb.threads;
+    /* memory available for output buffer */
+    out_buf_size = (size_t)atoi(parm.memory->answer) * (1 << 20);
+    /* size_t is unsigned, check if any memory is left for output buffer */
+    if (out_buf_size <= in_buf_size)
+        out_buf_size = 0;
+    else
+        out_buf_size -= in_buf_size;
+    /* number of buffered rows for all output maps */
+    brows = out_buf_size / (sizeof(DCELL) * ncols * num_outputs);
+    /* set the output buffer rows to be at most covering the entire map */
+    if (brows > nrows) {
+        brows = nrows;
+    }
+    /* but at least the number of threads */
+    if (brows < ncb.threads) {
+        brows = ncb.threads;
+    }
+
     /* read the weights */
     weights = 0;
     ncb.weights = NULL;

raster/r.patch/main.c

@@ -41,7 +41,7 @@ int main(int argc, char *argv[])
     int colr_ok;
     int outfd;
     RASTER_MAP_TYPE out_type, map_type;
-    size_t out_cell_size;
+    size_t out_cell_size, in_buf_size, out_buf_size;
     struct History history;
     void **presult, **patch;
     void *outbuf;
@@ -135,7 +135,7 @@ int main(int argc, char *argv[])
     for (t = 0; t < nprocs; t++)
         infd[t] = G_malloc(nfiles * sizeof(int));
     thread_statf = G_malloc(nprocs * (nfiles * sizeof(struct Cell_stats)));
-    for (int t = 0; t < nprocs; t++) {
+    for (t = 0; t < nprocs; t++) {
         thread_statf[t] = G_malloc(nfiles * sizeof(struct Cell_stats));
     }
     cellhd = G_malloc(nfiles * sizeof(struct Cell_head));
@@ -180,7 +180,17 @@ int main(int argc, char *argv[])
     nrows = Rast_window_rows();
     ncols = Rast_window_cols();
 
-    bufrows = atoi(memory->answer) * (((1 << 20) / out_cell_size) / ncols);
+    /* memory reserved for presult and patch */
+    in_buf_size = out_cell_size * ncols * nprocs * 2;
+    /* memory available for output buffer */
+    out_buf_size = (size_t)atoi(memory->answer) * (1 << 20);
+    /* size_t is unsigned, check if any memory is left for output buffer */
+    if (out_buf_size <= in_buf_size)
+        out_buf_size = 0;
+    else
+        out_buf_size -= in_buf_size;
+    /* number of buffered output rows */
+    bufrows = out_buf_size / (out_cell_size * ncols);
     /* set the output buffer rows to be at most covering the entire map */
     if (bufrows > nrows) {
         bufrows = nrows;

raster/r.resamp.filter/main.c

@@ -355,7 +355,6 @@ static void filter(void)
                 if (row0 >= read_row && row0 < read_row + num_rows) {
                     int m = row0 - read_row;
                     int n = read_row + num_rows - row0;
-                    int i;
 
                     for (i = 0; i < n; i++) {
                         DCELL *tmp = bufs[t_id][i];
@@ -415,6 +414,7 @@ int main(int argc, char *argv[])
     char title[64];
     int i, t;
     int nprocs;
+    size_t in_buf_size, out_buf_size;
 
     G_gisinit(argv[0]);
 
@@ -623,11 +623,25 @@ int main(int argc, char *argv[])
     Rast_set_input_window(&src_w);
     Rast_set_output_window(&dst_w);
 
-    bufrows =
-        atoi(parm.memory->answer) * (((1 << 20) / sizeof(DCELL)) / dst_w.cols);
+    /* memory reserved for input */
+    in_buf_size = dst_w.cols * sizeof(DCELL) * row_scale * nprocs;
+    /* memory available for output buffer */
+    out_buf_size = (size_t)atoi(parm.memory->answer) * (1 << 20);
+    /* size_t is unsigned, check if any memory is left for output buffer */
+    if (out_buf_size <= in_buf_size)
+        out_buf_size = 0;
+    else
+        out_buf_size -= in_buf_size;
+    /* number of buffered output rows */
+    bufrows = out_buf_size / (sizeof(DCELL) * dst_w.cols);
+    /* set the output buffer rows to be at most covering the entire map */
     if (bufrows > dst_w.rows) {
         bufrows = dst_w.rows;
     }
+    /* but at least the number of threads */
+    if (bufrows < nprocs) {
+        bufrows = nprocs;
+    }
 
     inbuf = G_malloc(nprocs * sizeof(DCELL *));
     for (t = 0; t < nprocs; t++)

raster/r.series/main.c

@@ -125,6 +125,7 @@ int main(int argc, char *argv[])
     int num_inputs;
     struct input **inputs = NULL;
     int bufrows;
+    size_t in_buf_size, out_buf_size;
 
 #if defined(_OPENMP)
     omp_lock_t fd_lock;
@@ -399,16 +400,6 @@ int main(int argc, char *argv[])
     nrows = Rast_window_rows();
     ncols = Rast_window_cols();
 
-    bufrows = atoi(parm.memory->answer) * (((1 << 20) / sizeof(DCELL)) / ncols);
-    /* set the output buffer rows to be at most covering the entire map */
-    if (bufrows > nrows) {
-        bufrows = nrows;
-    }
-    /* but at least the number of threads */
-    if (bufrows < nprocs) {
-        bufrows = nprocs;
-    }
-
     /* set the locks for lazily opening raster files */
 #if defined(_OPENMP)
     if (flag.lazy->answer && threaded) {
@@ -429,6 +420,26 @@ int main(int argc, char *argv[])
 
     outputs = G_calloc(num_outputs, sizeof(struct output));
 
+    /* memory reserved for input */
+    in_buf_size = ncols * sizeof(DCELL) * num_inputs * nprocs;
+    /* memory available for output buffer */
+    out_buf_size = (size_t)atoi(parm.memory->answer) * (1 << 20);
+    /* size_t is unsigned, check if any memory is left for output buffer */
+    if (out_buf_size <= in_buf_size)
+        out_buf_size = 0;
+    else
+        out_buf_size -= in_buf_size;
+    /* number of buffered rows for all output maps */
+    bufrows = out_buf_size / (sizeof(DCELL) * ncols * num_outputs);
+    /* set the output buffer rows to be at most covering the entire map */
+    if (bufrows > nrows) {
+        bufrows = nrows;
+    }
+    /* but at least the number of threads */
+    if (bufrows < nprocs) {
+        bufrows = nprocs;
+    }
+
     for (i = 0; i < num_outputs; i++) {
         struct output *out = &outputs[i];
         const char *output_name = parm.output->answers[i];