On Mon, 25 Oct 2010 11:28:27 +0800
Wu Fengguang <fengguang.wu@xxxxxxxxx> wrote:
> On Mon, Oct 25, 2010 at 11:05:50AM +0800, KAMEZAWA Hiroyuki wrote:
> > On Mon, 25 Oct 2010 10:57:03 +0800
> > Wu Fengguang <fengguang.wu@xxxxxxxxx> wrote:
> >
> > > On Mon, Oct 25, 2010 at 10:40:17AM +0800, KAMEZAWA Hiroyuki wrote:
> > > > On Mon, 25 Oct 2010 10:47:31 +0800
> > > > Bob Liu <lliubbo@xxxxxxxxx> wrote:
> > > >
> > > > > It's normal for isolate_lru_page() to fail at times. The failures are
> > > > > typically temporal and may well go away when offline_pages() retries
> > > > > the call. So it seems more reasonable to migrate as much as possible
> > > > > to increase the chance of complete success in next retry.
> > > > >
> > > > > This patch remove page_count() check and remove putback_lru_pages() and
> > > > > call migrate_pages() regardless of not_managed to reduce failure as much
> > > > > as possible.
> > > > >
> > > > > Signed-off-by: Bob Liu <lliubbo@xxxxxxxxx>
> > > >
> > > > -EBUSY should be returned.
> > >
> > > It does return -EBUSY when ALL pages cannot be isolated from LRU (or
> > > is non-LRU pages at all). That means offline_pages() will repeat calls
> > > to do_migrate_range() as fast as possible as long as it can make
> > > progress.
> > >
> > I read the patch wrong ? "ret = -EBUSY" is dropped and "ret" will be
> > 0 or just a return code of migrate_page().
>
> for () {
> ret = isolate_lru_page(page);
> }
>
> if (list_empty(&source))
> goto out;
>
> out:
> return ret;
>
> So do_migrate_range() will return -EBUSY if the last isolate_lru_page() returns
> -EBUSY.
>
Then this patch should be put onto "immediately quit loop when not_managed++" patch.
Please write it in description or make a patch series which other guys can see it.
Thanks,
-Kame
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