On Mon, 23 May 2016, Andrew Morton wrote:
> On Fri, 20 May 2016 15:31:21 +0200 Michal Hocko <mhocko@xxxxxxxxxx> wrote:
> > On Fri 20-05-16 15:19:12, Vlastimil Babka wrote:
> > > On 05/20/2016 03:06 PM, Michal Hocko wrote:
> > [...]
> > > > Why don't we need also to count also retries?
> > >
> > > We could, but not like you suggest.
> > >
> > > > ---
> > > > diff --git a/mm/migrate.c b/mm/migrate.c
> > > > index 53ab6398e7a2..ef9c5211ae3c 100644
> > > > --- a/mm/migrate.c
> > > > +++ b/mm/migrate.c
> > > > @@ -1190,9 +1190,9 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
> > > > }
> > > > }
> > > > }
> > > > +out:
> > > > nr_failed += retry;
> > > > rc = nr_failed;
> > >
> > > This overwrites rc == -ENOMEM, which at least compaction needs to recognize.
> > > But we could duplicate "nr_failed += retry" in the case -ENOMEM.
> >
> > Right you are. So we should do
> > ---
> > diff --git a/mm/migrate.c b/mm/migrate.c
> > index 53ab6398e7a2..123fed94022b 100644
> > --- a/mm/migrate.c
> > +++ b/mm/migrate.c
> > @@ -1171,6 +1171,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
> >
> > switch(rc) {
> > case -ENOMEM:
> > + nr_failed += retry + 1;
> > goto out;
> > case -EAGAIN:
> > retry++;
> >
> >
>
> argh, this was lost. Please resend as a real patch sometime?
It's not correct. "retry" is reset to 0 each time around the
loop, and it's only a meaningful number to add on to nr_failed, in
the case when we've gone through the whole list: not in this "goto
out" case. We could add another loop to count how many are left
when we hit -ENOMEM, and add that on to nr_failed; but I'm not
convinced that it's worth the bother.
Hugh
--
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>