Hi Michal, On Wed, Apr 27, 2022 at 04:09:28PM +0200, Michal Koutný wrote: > Hello David. > > On Sat, Apr 23, 2022 at 08:56:19AM -0700, David Vernet <void@xxxxxxxxxxxxx> wrote: > > This unfortunately broke the memcg tests, which asserts that a sibling > > that experienced reclaim but had a memory.low value of 0, would not > > observe any memory.low events. This patch updates test_memcg_low() to > > account for the new behavior introduced by memory_recursiveprot. > > I think the test is correct, there should be no (not even recursive) > protection in this particular case (when the remaining siblings consume > all of parental protection). > > This should be fixed in the kernel (see also [1], no updates from me yet > :-/) > > Michal > > [1] https://lore.kernel.org/lkml/20220322182248.29121-1-mkoutny@xxxxxxxx/ > I see, thanks for sharing that context. I think I see your point about the implementation of the reclaim mechanism potentially overcounting, but my interpretation of the rest of that discussion with Roman is that we haven't yet decided whether we don't want to propagate memory.low events from children cgroups with memory.low == 0. Or at the very least, some more justification was requested on why not counting such events was prudent. Would you be ok with merging this patch so that the cgroup selftests can pass again based on the current behavior of the kernel, and we can then revert the changes to test_memcg_low() later on if and when we decide that we don't want to propagate memory.low events for memory.low == 0 children? Thanks, David
