On Tue, Oct 15, 2024 at 9:57 PM Yu Zhao <yuzhao@xxxxxxxxxx> wrote:
>
> On Mon, Oct 14, 2024 at 4:12 PM Wei Xu <weixugc@xxxxxxxxxx> wrote:
> >
> > lru_gen_shrink_node() unconditionally clears kswapd_failures, which
> > can prevent kswapd from sleeping and cause 100% kswapd cpu usage even
> > when kswapd repeatedly fails to make progress in reclaim.
> >
> > Only clear kswap_failures in lru_gen_shrink_node() if reclaim makes
> > some progress, similar to shrink_node().
> >
> > Fixes: e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists")
> > Signed-off-by: Wei Xu <weixugc@xxxxxxxxxx>
> > ---
> > mm/vmscan.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/mm/vmscan.c b/mm/vmscan.c
> > index 50dc06d55b1d..9d1e1c4e383d 100644
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -4970,8 +4970,8 @@ static void lru_gen_shrink_node(struct pglist_data *pgdat, struct scan_control *
> >
> > blk_finish_plug(&plug);
> > done:
>
> Nit: the "done:" isn't used anymore, so better just remove it.
>
"goto done" is still used at the beginning of lru_gen_shrink_node().
We can refactor the code to remove it. But it is better to be handled
in a separate change.
> > - /* kswapd should never fail */
> > - pgdat->kswapd_failures = 0;
> > + if (sc->nr_reclaimed > reclaimed)
> > + pgdat->kswapd_failures = 0;
> > }
> >
> > /******************************************************************************
> > --
> > 2.47.0.rc1.288.g06298d1525-goog
> >
> >
