Re: [PATCH 0/12] memcg updates v5

From: KAMEZAWA Hiroyuki
Date: Fri Sep 26 2008 - 06:29:28 EST


On Fri, 26 Sep 2008 15:01:46 +0530
Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:

> KAMEZAWA Hiroyuki wrote:
> > On Fri, 26 Sep 2008 13:48:58 +0530
> > Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:
> >
> >> KAMEZAWA Hiroyuki wrote:
> >>> Hi, I updated the stack and reflected comments.
> >>> Against the latest mmotm. (rc7-mm1)
> >>>
> >>> Major changes from previous one is
> >>> - page_cgroup allocation/lookup manner is changed.
> >>> all FLATMEM/DISCONTIGMEM/SPARSEMEM and MEMORY_HOTPLUG is supported.
> >>> - force_empty is totally rewritten. and a problem that "force_empty takes long time"
> >>> in previous version is fixed (I think...)
> >>> - reordered patches.
> >>> - first half are easy ones.
> >>> - second half are big ones.
> >>>
> >>> I'm still testing with full debug option. No problem found yet.
> >>> (I'm afraid of race condition which have not been caught yet.)
> >>>
> >>> [1/12] avoid accounting special mappings not on LRU. (fix)
> >>> [2/12] move charege() call to swapped-in page under lock_page() (clean up)
> >>> [3/12] make root cgroup to be unlimited. (change semantics.)
> >>> [4/12] make page->mapping NULL before calling uncharge (clean up)
> >>> [5/12] make page->flags to use atomic ops. (changes in infrastructure)
> >>> [6/12] optimize stat. (clean up)
> >>> [7/12] add support function for moving account. (new function)
> >>> [8/12] rewrite force_empty to use move_account. (change semantics.)
> >>> [9/12] allocate all page_cgroup at boot. (changes in infrastructure)
> >>> [10/12] free page_cgroup from LRU in lazy way (optimize)
> >>> [11/12] add page_cgroup to LRU in lazy way (optimize)
> >>> [12/12] fix race at charging swap (fix by new logic.)
> >>>
> >>> *Any* comment is welcome.
> >> Kame,
> >>
> >> I'm beginning to review test the patches now. It would be really nice to split
> >> the development patches from the maintenance ones. I think the full patchset has
> >> too many things and is confusing to look at.
> >>
> > I hope I can do....but maybe difficult.
> > If you give me ack, 1,2,4,6, can be pushed at early stage.
>
> I think (1) might be OK, except for the accounting issues pointed out (change in
> behaviour visible to end user again, sigh! :( ).
But it was just a BUG from my point of view...

> Is (1) a serious issue?
considering force_empty(), it's serious.

> (2) seems OK, except for the locking change for mark_page_accessed. I am looking at
> (4) and (6) currently.
>
Thanks,
-Kmae

> --
> Balbir
>

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