On Fri, 2012-07-20 at 12:19 +0900, Kamezawa Hiroyuki wrote:
>
> When I added batching, I didn't touch page-reclaim path because it delays
> res_counter_uncharge() and make more threads run into page reclaim.
> But, from above score, bactching seems required.
>
> And because of current design of per-zone-per-memcg-LRU, batching
> works very very well....all lru pages shrink_page_list() scans are on
> the same memcg.
>
> BTW, it's better to show 'how much improved' in patch description..
I didn't put the specific improvement in patch description as the
performance change is specific to my machine and benchmark and
improvement could be variable for others. However, I did include the
specific number in the body of my message. Hope that is enough.
>
>
> > ---
> > Signed-off-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
> > diff --git a/mm/vmscan.c b/mm/vmscan.c
> > index 33dc256..aac5672 100644
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -779,6 +779,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
> >
> > cond_resched();
> >
> > + mem_cgroup_uncharge_start();
> > while (!list_empty(page_list)) {
> > enum page_references references;
> > struct address_space *mapping;
> > @@ -1026,6 +1027,7 @@ keep_lumpy:
> >
> > list_splice(&ret_pages, page_list);
> > count_vm_events(PGACTIVATE, pgactivate);
> > + mem_cgroup_uncharge_end();
>
> I guess placing mem_cgroup_uncharge_end() just after the loop may be better looking.
I initially though of doing that. I later pushed the statement down to
after list_splice(&ret_pages, page_list) as that's when the page reclaim
is actually completed. It probably doesn't matter one way or the other.
I can move it to just after the loop if people think that's better.
Thanks for reviewing the change.
Tim
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>