Re: [PATCH v2 2/3] CMA: aggressively allocate the pages on cma reserved memory when not used

[Gioh Kim]

I found 2 problems at my platform.

1st is occured when I set CMA size 528MB and total memory is 960MB.
I print some values in adjust_managed_cma_page_count(),
the total value becomes 105439 and cma value 131072.
Finally movable value becomes negative value.

The total value 105439 means 411MB.
Is the zone->managed_pages value pages amount except the CMA?
I think zone->managed_pages value is including CMA size but it's value is strange.

2nd is a kernel panic at __netdev_alloc_skb().
I'm not sure it is caused by the CMA.
I'm checking it again and going to send you another report with detail call-stacks.



2014-05-30 ìí 11:23, Joonsoo Kim ì ê:
> 2014-05-30 16:53 GMT+09:00 Gioh Kim <gioh.kim@xxxxxxx>:
> > Joonsoo,
> >
> > I'm attaching a patch for combination of __rmqueue and __rmqueue_cma.
> > I didn't test fully but my board is turned on and working well if no frequent memory allocations.
> >
> > I'm sorry to send not-tested code.
> > I just want to report this during your working hour ;-)
> >
> > I'm testing this this evening and reporting next week.
> > Have a nice weekend!
>
> Thanks Gioh. :)
>
> > -------------------------------------- 8< -----------------------------------------
> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > index 7f97767..9ced736 100644
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> > @@ -964,7 +964,7 @@ static int fallbacks[MIGRATE_TYPES][4] = {
> >          [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,     MIGRATE_R
> >   #ifdef CONFIG_CMA
> >          [MIGRATE_MOVABLE]     = { MIGRATE_CMA,         MIGRATE_RECLAIMABLE, MIGRATE_U
> > -       [MIGRATE_CMA]         = { MIGRATE_RESERVE }, /* Never used */
> > +       [MIGRATE_CMA]         = { MIGRATE_MOVABLE,     MIGRATE_RECLAIMABLE, MIGRATE_U
>
> I don't want to use __rmqueue_fallback() for CMA.
> __rmqueue_fallback() takes big order page rather than small order page
> in order to steal large amount of pages and continue to use them in
> next allocation attempts.
> We can use CMA pages on limited cases, so stealing some pages from
> other migrate type
> to CMA type isn't good idea to me.
>
> Thanks.
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