Hi SeongJae, On Sun, 17 Mar 2024 12:13:57 -0700 SeongJae Park <sj@xxxxxxxxxx> wrote: > On Sun, 17 Mar 2024 08:31:44 -0700 SeongJae Park <sj@xxxxxxxxxx> wrote: > > > Hi Honggyu, > > > > On Sun, 17 Mar 2024 17:36:29 +0900 Honggyu Kim <honggyu.kim@xxxxxx> wrote: > > > > > Hi SeongJae, > > > > > > Thanks for the confirmation. I have a few comments on young filter so > > > please read the inline comments again. > > > > > > On Wed, 12 Mar 2024 08:53:00 -0800 SeongJae Park <sj@xxxxxxxxxx> wrote: > > > > Hi Honggyu, > [...] > > > Thanks. I see that it works fine, but I would like to have more > > > discussion about "young" filter. What I think about filter is that if I > > > apply "young" filter "true" for demotion, then the action applies only > > > for "young" pages, but the current implementation works opposite. > > > > > > I understand the function name of internal implementation is > > > "damos_pa_filter_out" so the basic action is filtering out, but the > > > cgroup filter works in the opposite way for now. > > > > Does memcg filter works in the opposite way? I don't think so because > > __damos_pa_filter_out() sets 'matches' as 'true' only if the the given folio is > > contained in the given memcg. 'young' filter also simply sets 'matches' as > > 'true' only if the given folio is young. > > > > If it works in the opposite way, it's a bug that need to be fixed. Please let > > me know if I'm missing something. > > I just read the DAMOS filters part of the documentation for DAMON sysfs > interface again. I believe it is explaining the meaning of 'matching' as I > intended to, as below: > > You can write ``Y`` or ``N`` to ``matching`` file to filter out pages that does > or does not match to the type, respectively. Then, the scheme's action will > not be applied to the pages that specified to be filtered out. > > But, I found the following example for memcg filter is wrong, as below: > > For example, below restricts a DAMOS action to be applied to only non-anonymous > pages of all memory cgroups except ``/having_care_already``.:: > > # echo 2 > nr_filters > # # filter out anonymous pages > echo anon > 0/type > echo Y > 0/matching > # # further filter out all cgroups except one at '/having_care_already' > echo memcg > 1/type > echo /having_care_already > 1/memcg_path > echo N > 1/matching > > Specifically, the last line of the commands should write 'Y' instead of 'N' to > do what explained. Without the fix, the action will be applied to only > non-anonymous pages of 'having_care_already' memcg. This is definitely wrong. > I will fix this soon. I'm unsure if this is what made you to believe memcg > DAMOS filter is working in the opposite way, though. I got confused not because of this. I just think it again that this user interface is better to be more intuitive as I mentioned in the previous thread. Thanks, Honggyu > > Thanks, > SJ > > [...]
