Update dataloaders.py (#9250)

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

utils/dataloaders.py

@@ -40,6 +40,7 @@ IMG_FORMATS = 'bmp', 'dng', 'jpeg', 'jpg', 'mpo', 'png', 'tif', 'tiff', 'webp',
 VID_FORMATS = 'asf', 'avi', 'gif', 'm4v', 'mkv', 'mov', 'mp4', 'mpeg', 'mpg', 'ts', 'wmv'  # include video suffixes
 BAR_FORMAT = '{l_bar}{bar:10}{r_bar}{bar:-10b}'  # tqdm bar format
 LOCAL_RANK = int(os.getenv('LOCAL_RANK', -1))  # https://pytorch.org/docs/stable/elastic/run.html
+PIN_MEMORY = str(os.getenv('PIN_MEMORY', True)).lower() == 'true'  # global pin_memory for dataloaders
 
 # Get orientation exif tag
 for orientation in ExifTags.TAGS.keys():
@@ -83,7 +84,7 @@ def exif_transpose(image):
             5: Image.TRANSPOSE,
             6: Image.ROTATE_270,
             7: Image.TRANSVERSE,
-            8: Image.ROTATE_90,}.get(orientation)
+            8: Image.ROTATE_90}.get(orientation)
         if method is not None:
             image = image.transpose(method)
             del exif[0x0112]
@@ -144,7 +145,7 @@ def create_dataloader(path,
                   shuffle=shuffle and sampler is None,
                   num_workers=nw,
                   sampler=sampler,
-                  pin_memory=True,
+                  pin_memory=PIN_MEMORY,
                   collate_fn=LoadImagesAndLabels.collate_fn4 if quad else LoadImagesAndLabels.collate_fn,
                   worker_init_fn=seed_worker,
                   generator=generator), dataset
@@ -1152,6 +1153,6 @@ def create_classification_dataloader(path,
                               shuffle=shuffle and sampler is None,
                               num_workers=nw,
                               sampler=sampler,
-                              pin_memory=True,
+                              pin_memory=PIN_MEMORY,
                               worker_init_fn=seed_worker,
                               generator=generator)  # or DataLoader(persistent_workers=True)