Bug 213123

Summary: The performance deteriorates because the ip_victor function is deleted.
Product: Networking Reporter: kircher (kircherlike)
Component: IPV4Assignee: Stephen Hemminger (stephen)
Status: NEW ---    
Severity: normal    
Priority: P1    
Hardware: All   
OS: Linux   
Kernel Version: 4.19.90 Subsystem:
Regression: No Bisected commit-id:

Description kircher 2021-05-18 07:31:29 UTC 
In the 4.19 kernel, we see that there is this commit

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/net/ipv4/ip_fragment.c?id=86e93e470cadedda9181a2bd9aee1d9d2e5e9c0f 

Before the integration, the ip_victor function is used to release the old fragmented data when the fragmented IP data occupies the fragmented buffer.

However, in the same scenario, the kernel of 4.19 discards all subsequent data until the 30-second buffer wait time set by ipfrag_time expires.
After this, subsequent fragmented data is received.