FRR config "no zebra nexthop kernel enable" increases system mem usage in T2 downstream LC

[ysmanman]

Is it platform specific

generic

Importance or Severity

High

Description of the bug

#23294 was integrated in msft-202405 .33 image. With this change, PerCpu mem usage ( in /proc/meminfo) in .33 image had increased a lot ( > ~2GB) on downstream LC in T2 chassis.

Steps to Reproduce

Load msft .32 and .33 on a T2 testbed and then check PerCpu & system mem usage each image.

Actual Behavior and Expected Behavior

The system & PerCpu mem usage has increased > 2GB in .33 image.

Relevant log output

Output of show version, show techsupport

Attach files (if any)

No response

[ysmanman]

@arlakshm @deepak-singhal0408 @rlhui @kenneth-arista

[ysmanman]

#23294 was reverted with the proper fix in FRR #18953. But the change was not reverted in 202405.

[deepak-singhal0408]

#23294 was reverted with the proper fix in FRR #18953. But the change was not reverted in 202405.

#18953 is present in 202405, "no zebra nexthop kernel enable" was reverted earlier but later brought back in 202405 via #23294

[judyjoseph]

Revert this "no zebra nexthop kernel enable" in 202405 branch + add test/fix for route earlier issue where kernel and zebra routes go out of sync

[deepak-singhal0408]

in 202405 all the required changes are merged..
Related PRs..
Azure/sonic-buildimage-msft#1908
Azure/sonic-buildimage-msft#1904
Enhance route-check to detect FRR Failed routes · Azure/sonic-utilities.msft@551cb96