Re: [PATCH v3 18/19] kselftests: cgroup: add kernel memory accounting tests

From: Vlastimil Babka
Date: Wed May 27 2020 - 13:00:53 EST

On 5/26/20 5:45 PM, Roman Gushchin wrote:
> On Tue, May 26, 2020 at 05:24:46PM +0200, Vlastimil Babka wrote:
>> 1 << 20 ?
>> Anyway I was getting this:
>> not ok 1 test_kmem_basic
>> ok 2 test_kmem_memcg_deletion
>> ok 3 test_kmem_proc_kpagecgroup
>> not ok 4 test_kmem_kernel_stacks
>> ok 5 test_kmem_dead_cgroups
>> Adding some debugging into kmem_basic I found I get memory.stat == 0 at this
>> point thus it fails the fixed test (otherwise it was failing the <= 0 test after
>> writing to memory.high). But it's just a VM spinned by virtme which has a very
>> simple init, so perhaps things are not as initialized as expected.
> Hm, it's strange, do you have any values in memory.stat::slab for any cgroups?
> Or can you send me your config (and kvm setup), I'll take a look.

Config is attached, KVM setup is just running virtme [1] on the git gree where I
compiled the kernel:

virtme-run --mods=auto --kdir /path/to/linux.git/

So there's only the cgroup the test creates, and the memry.stat::slab is zero
after alloc_dcache(). Although I can see by strace that it does all those
stat()'s. Also /proc/slabinfo also doesn't seem to be increasing number of
dentries. Could be that because root fs is 9p in virtme?


> Btw, thank you very much for reviewing the series! I appreciate it.
> I'll integrate your feedback into the next version, which I'm working on right now.
> Thanks!

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