Messages in this thread | | | Date | Tue, 19 Jan 2021 19:49:49 -0800 | From | Roman Gushchin <> | Subject | Re: [PATCH] mm: net: memcg accounting for TCP rx zerocopy |
| |
On Tue, Jan 19, 2021 at 07:31:51PM -0800, Arjun Roy wrote: > On Wed, Jan 13, 2021 at 11:55 AM Shakeel Butt <shakeelb@google.com> wrote: > > > > On Wed, Jan 13, 2021 at 11:49 AM Yang Shi <shy828301@gmail.com> wrote: > > > > > > On Wed, Jan 13, 2021 at 11:13 AM Shakeel Butt <shakeelb@google.com> wrote: > > > > > > > > On Wed, Jan 13, 2021 at 10:43 AM Roman Gushchin <guro@fb.com> wrote: > > > > > > > > > > On Tue, Jan 12, 2021 at 04:18:44PM -0800, Shakeel Butt wrote: > > > > > > On Tue, Jan 12, 2021 at 4:12 PM Arjun Roy <arjunroy@google.com> wrote: > > > > > > > > > > > > > > On Tue, Jan 12, 2021 at 3:48 PM Roman Gushchin <guro@fb.com> wrote: > > > > > > > > > > > > > > [snip] > > > > > > > > Historically we have a corresponding vmstat counter to each charged page. > > > > > > > > It helps with finding accounting/stastistics issues: we can check that > > > > > > > > memory.current ~= anon + file + sock + slab + percpu + stack. > > > > > > > > It would be nice to preserve such ability. > > > > > > > > > > > > > > > > > > > > > > Perhaps one option would be to have it count as a file page, or have a > > > > > > > new category. > > > > > > > > > > > > > > > > > > > Oh these are actually already accounted for in NR_FILE_MAPPED. > > > > > > > > > > Well, it's confusing. Can't we fix this by looking at the new page memcg flag? > > > > > > > > Yes we can. I am inclined more towards just using NR_FILE_PAGES (as > > > > Arjun suggested) instead of adding a new metric. > > > > > > IMHO I tend to agree with Roman, it sounds confusing. I'm not sure how > > > people relies on the counter to have ballpark estimation about the > > > amount of reclaimable memory for specific memcg, but they are > > > unreclaimable. And, I don't think they are accounted to > > > NR_ACTIVE_FILE/NR_INACTIVE_FILE, right? So, the disparity between > > > NR_FILE_PAGES and NR_{IN}ACTIVE_FILE may be confusing either. > > > > > > > Please note that due to shmem/tmpfs there is already disparity between > > NR_FILE_PAGES and NR_{IN}ACTIVE_FILE. > > > > BTW I don't have a strong opinion against adding a new metric. If > > there is consensus we can add one. > > Just wanted to see if there were any thoughts/consensus on what the > best way to proceed is - should there be a v2 patch with specific > changes? Or is NR_FILE_PAGES alright?
I struggle to see why these pages should be considered file pages. (NR_FILE_MAPPED is a different story). I'm ok with slab/kmem, sock and a new metric, we can discuss what's the best option out of three.
> And similar query, for pre-charging vs. post charging.
IMO double accounting is bad. If it means post charging, I vote for post charging.
Thanks!
| |