Got error 'Cannot allocate memory'

Code like this:

trainset = COCODataset('data.txt', (416,416), True, is_debug=True)
	trainloader = DataLoader(trainset, batch_size=8,shuffle=False, num_workers=4)

	net = Mynet(file)
	if gpu:
	optimizer = optim.SGD(net.parameters(), lr=0.01)
	for epoch in range(Epochs):
		for i, sample in enumerate(trainloader):
			images, labels = sample['image'], sample['label']

I got an error here for i, sample in enumerate(trainloader): :
OSError: [Errno 12] Cannot allocate memory
What’s that mean?My GPU memory-usage is 1283MiB / 8118MiB

The error message seems to point to your RAM, not the GPU memory.
Could you check it with free -h and see how much memory is left?

This particular error message can be triggered, if new processes would like to spawn / fork and there is not enough memory left.

how can I trigger such particular error message?
Is there any code implementation in pytorch for that?
I obtained this memmory allocation error in loading images from KITTI dataset.

If you are trying to load all images into your RAM, you might trigger this error.
Did you observe the RAM usage?

$ free -h shows the available memory decreasing to almost ZERO and this is the error eventually I get:

RuntimeError: [enforce fail at CPUAllocator.cpp:64] . DefaultCPUAllocator: can't allocate memory: you tried to allocate 12976128000 bytes. Error code 12 (Cannot allocate memory

what’s a better approach to load images or read images without allocating RAM ?

Usually you would lazily load the samples using a Dataset and wrap it in a DataLoader to create batches, shuffle the data, use multiple workers to load each batch etc.

Have a look at the Data loading tutorial for more information on how to write a custom Dataset.

try to set overcommit_memory to 0 in /etc/sysctl.conf

i also meet the memory leak problem. but i dont know how to correct it…

Traceback (most recent call last):
  File "", line 169, in <module>
  File "", line 143, in main
    val_loss, val_acc, val_bacc = validate(model, val_loader, criterion, taskNum, weights=attrWeights)
  File "../", line 30, in validate
    for i, (inputs, labels) in enumerate(val_loader):
  File "/home/user1/miniconda3/lib/python3.7/site-packages/torch/utils/data/", line 193, in __iter__
    return _DataLoaderIter(self)
  File "/home/user1/miniconda3/lib/python3.7/site-packages/torch/utils/data/", line 469, in __init__
  File "/home/user1/miniconda3/lib/python3.7/multiprocessing/", line 112, in start
    self._popen = self._Popen(self)
  File "/home/user1/miniconda3/lib/python3.7/multiprocessing/", line 223, in _Popen
    return _default_context.get_context().Process._Popen(process_obj)
  File "/home/user1/miniconda3/lib/python3.7/multiprocessing/", line 277, in _Popen
    return Popen(process_obj)
  File "/home/user1/miniconda3/lib/python3.7/multiprocessing/", line 20, in __init__
  File "/home/user1/miniconda3/lib/python3.7/multiprocessing/", line 70, in _launch = os.fork()
OSError: [Errno 12] Cannot allocate memory