Hello,
We discovered that the CONFIG_INFINIBAND_IRDMA configuration option in the linux kernel is causing excessive memory usage on idle mode on specific servers like the DELL VEP4600 (https://www.dell.com/en-us/shop/ipovw/virtual-edge-platform-4600.
By default we were using Debian's linux-image-6.1.0-13-amd64 which is the stable 6.1.55-1 amd64, we then compiled the kernel again with the same config file from the stable 6.1.55 tag and had the same problem. We were able to resolve the memory problem by removing the `CONFIG_INFINIBAND_IRDMA` option from the kernel config.
The tag used to reproduce the problem is v6.1.55. adding the following config `CONFIG_INFINIBAND_IRDMA=m` causes the excessive memory usage to go from 1.4Gb to 7Gb.
Here are the 2 config files used and the outputs showing the Memory usage in both cases.
Do you have any ideas regarding this bug, we only had this bug on this specific hardware model mentioned above.
Debian version of the linux 6.1.55:
#uname -a Linux wibox 6.1.0-13-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.1.55-1 (2023-09-29) x86_64 GNU/Linux
#free -m total used free shared buff/cache available Mem: 15724 6757 8840 3 410 8967 Swap: 0 0 0
Compiled version without INFINIBAND:
#uname -a Linux wibox 6.1.55-without-infiniband #75 SMP PREEMPT_DYNAMIC Mon Apr 29 19:06:23 CEST 2024 x86_64 GNU/Linux
#free -m total used free shared buff/cache available Mem: 15724 1480 13339 3 1205 14244 Swap: 0 0 0
Thank you,