System memory flow management

1. A method for wireless communications implemented by a user equipment (UE), comprising:

transmitting, by the UE, a data message to a receiver via a first radio access technology of the UE;

storing the data message in a retransmission buffer;

dynamically scaling up or down, by the UE, a size of an acknowledgement window based at least in part on available memory of the UE, wherein the size of the acknowledgement window indicates a threshold quantity for data messages awaiting acknowledgement in the retransmission buffer, and wherein a system memory utilization threshold is less than the size of the acknowledgement window;

transmitting, via the first radio access technology, a feedback request to the receiver in a subsequent data message based at least in part on the system memory utilization threshold for the retransmission buffer being satisfied due to storage of the data message; and

transmitting a low system memory indication to a second radio access technology of the UE different from the first radio access technology based at least in part on the system memory utilization threshold for the retransmission buffer being satisfied.

2. The method of claim 1 , wherein the transmitting the feedback request comprises:

transmitting the subsequent data message that includes a poll bit set to a defined value to indicate the feedback request.

3. The method of claim 1 , further comprising:

transmitting, via the second radio access technology, a second feedback request to the receiver or a second receiver in a second subsequent data message based at least in part on the low system memory indication.

4. The method of claim 1 , further comprising:

monitoring for a feedback response from the receiver corresponding to the data message based at least in part on transmitting the feedback request.

5. The method of claim 4 , wherein the monitoring further comprises:

receiving the feedback response from the receiver; and

retransmitting the data message to the receiver based at least in part on the feedback response.

6. The method of claim 4 , wherein the monitoring further comprises:

receiving the feedback response from the receiver; and

removing the data message from the retransmission buffer based at least in part on the feedback response.

7. The method of claim 6 , further comprising:

refraining from transmitting a second feedback request to the receiver in a second subsequent data message based at least in part on the system memory utilization threshold for the retransmission buffer not being satisfied due to removal of the data message from the retransmission buffer.

8. The method of claim 7 , wherein the refraining from transmitting the second feedback request comprises:

refraining from transmitting the second feedback request in the second subsequent data message based at least in part on a system memory availability threshold for the retransmission buffer being satisfied due to removal of the data message from the retransmission buffer.

9. The method of claim 4 , wherein the monitoring further comprises:

retransmitting the data message to the receiver based at least in part on the feedback response not being received within a time period.

10. The method of claim 4 , wherein the feedback response indicates that the receiver successfully received the data message or did not successfully receive the data message.

11. The method of claim 1 , wherein the system memory utilization threshold is less than a preconfigured size.

12. The method of claim 1 , wherein the size of the acknowledgement window of a transmitter entity of the UE is based at least in part on the available memory of the UE.

13. The method of claim 12 , wherein dynamically scaling up or down the size comprises:

dynamically scaling up or down, by a transmitter entity of the UE, the size based at least in part on memory usage by the UE.

14. The method of claim 1 , wherein the data message is a radio link control protocol data unit transmission.

15. An apparatus for wireless communications at a user equipment (UE), comprising:

a processor, and

memory coupled with the processor, wherein the memory comprises instructions executable by the processor to cause the apparatus to:

transmit, by the apparatus, a data message to a receiver via a first radio access technology of the apparatus;

store the data message in a retransmission buffer;

dynamically scale up or down a size of an acknowledgement window based at least in part on available memory of the UE, wherein the size of the acknowledgement window indicates a threshold quantity for data messages awaiting acknowledgement in the retransmission buffer, and wherein a system memory utilization threshold is less than the size of the acknowledgement window;

transmit, via the first radio access technology, a feedback request to the receiver in a subsequent data message based at least in part on the system memory utilization threshold for the retransmission buffer being satisfied due to storage of the data message; and

transmit a low system memory indication to a second radio access technology of the apparatus different from the first radio access technology based at least in part on the system memory utilization threshold for the retransmission buffer being satisfied.

16. The apparatus of claim 15 , wherein the instructions to transmit the feedback request are executable by the processor to cause the apparatus to:

transmit the subsequent data message that includes a poll bit set to a defined value to indicate the feedback request.

17. The apparatus of claim 15 , wherein the instructions are further executable by the processor to cause the apparatus to:

transmit, via the second radio access technology, a second feedback request to the receiver or a second receiver in a second subsequent data message based at least in part on the low system memory indication.

18. The apparatus of claim 15 , wherein the instructions are further executable by the processor to cause the apparatus to:

monitor for a feedback response from the receiver corresponding to the data message based at least in part on transmitting the feedback request.

19. The apparatus of claim 18 , wherein the instructions to monitor are executable by the processor to cause the apparatus to:

receive the feedback response from the receiver; and

retransmit the data message to the receiver based at least in part on the feedback response.

20. The apparatus of claim 18 , wherein the instructions to monitor are executable by the processor to cause the apparatus to:

receive the feedback response from the receiver; and

remove the data message from the retransmission buffer based at least in part on the feedback response.

21. The apparatus of claim 20 , wherein the instructions are further executable by the processor to cause the apparatus to:

refrain from transmitting a second feedback request to the receiver in a second subsequent data message based at least in part on the system memory utilization threshold for the retransmission buffer not being satisfied due to removal of the data message from the retransmission buffer.

22. The apparatus of claim 21 , wherein the instructions to refrain from transmitting the second feedback request are executable by the processor to cause the apparatus to:

refrain from transmitting the second feedback request in the second subsequent data message based at least in part on a system memory availability threshold for the retransmission buffer being satisfied due to removal of the data message from the retransmission buffer.

23. The apparatus of claim 18 , wherein the instructions to monitor are executable by the processor to cause the apparatus to:

retransmit the data message to the receiver based at least in part on the feedback response not being received within a time period.

24. The apparatus of claim 18 , wherein the feedback response indicates that the receiver successfully received the data message or did not successfully receive the data message.

25. The apparatus of claim 15 , wherein the system memory utilization threshold is less than a preconfigured size.

26. An apparatus for wireless communications at a user equipment (UE), comprising:

means for transmitting, by the apparatus, a data message to a receiver via a first radio access technology of the apparatus;

means for storing the data message in a retransmission buffer;

means for dynamically scaling up or down, by the UE, a size of an acknowledgement window based at least in part on available memory of the UE, wherein the size of the acknowledgement window indicates a threshold quantity for data messages awaiting acknowledgement in the retransmission buffer, and wherein a system memory utilization threshold is less than the size of the acknowledgement window;

means for transmitting, via the first radio access technology, a feedback request to the receiver in a subsequent data message based at least in part on the system memory utilization threshold for the retransmission buffer being satisfied due to storage of the data message; and

means for transmitting a low system memory indication to a second radio access technology of the apparatus different from the first radio access technology based at least in part on the system memory utilization threshold for the retransmission buffer being satisfied.

27. A non-transitory computer-readable medium storing code for wireless communications by a user equipment (UE), the code comprising instructions executable by a processor to:

transmit, by the UE, a data message to a receiver via a first radio access technology of the UE;

store the data message in a retransmission buffer;

dynamically scaling up or down, by the UE, a size of an acknowledgement window based at least in part on available memory of the UE, wherein the size of the acknowledgement window indicates a threshold quantity for data messages awaiting acknowledgement in the retransmission buffer, and wherein a system memory utilization threshold is less than the size of the acknowledgement window;

transmit, via the first radio access technology, a feedback request to the receiver in a subsequent data message based at least in part on the system memory utilization threshold for the retransmission buffer being satisfied due to storage of the data message; and

transmit a low system memory indication to a second radio access technology of the UE different from the first radio access technology based at least in part on the system memory utilization threshold for the retransmission buffer being satisfied.