On 8/28/25 6:00 PM, Kuniyuki Iwashima wrote:
The test does the following for IPv4/IPv6 x TCP/UDP sockets with/without BPF prog. 1. Create socket pairs 2. Send a bunch of data that requires more than 256 pages 3. Read memory_allocated from the 3rd column in /proc/net/protocols 4. Check if unread data is charged to memory_allocated If BPF prog is attached, memory_allocated should not be changed, but we allow a small error (up to 10 pages) in case other processes on the host use some amounts of TCP/UDP memory. At 2., the test actually sends more than 1024 pages because the sysctl net.core.mem_pcpu_rsv is 256 is by default, which means 256 pages are buffered per cpu before reporting to sk->sk_prot->memory_allocated. BUF_SINGLE (1024) * NR_SEND (64) * NR_SOCKETS (64) / 4096 = 1024 pages When I reduced it to 512 pages, the following assertion for the non-isolated case got flaky. ASSERT_GT(memory_allocated[1], memory_allocated[0] + 256, ...) Another contributor to slowness is 150ms sleep to make sure 1 RCU grace period passes because UDP recv queue is destroyed after that.
There is a kern_sync_rcu() in testing_helpers.c.
# time ./test_progs -t sk_memcg #370/1 sk_memcg/TCP :OK #370/2 sk_memcg/UDP :OK #370/3 sk_memcg/TCPv6 :OK #370/4 sk_memcg/UDPv6 :OK #370 sk_memcg:OK Summary: 1/4 PASSED, 0 SKIPPED, 0 FAILED real 0m1.214s user 0m0.014s sys 0m0.318s
Thanks. It finished much faster in my setup also comparing with the earlier revision. However, it is a bit flaky when I run it in a loop:
check_isolated:FAIL:not isolated unexpected not isolated: actual 861 <= expected 861 I usually can hit this at ~40-th iteration.
