lkml.org 
[lkml]   [2020]   [Feb]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    Date
    SubjectRe: [PATCH] mm: Stop kswapd early when nothing's waiting for it to free pages
    On Wed, Feb 26, 2020 at 4:15 AM Hillf Danton <hdanton@sina.com> wrote:
    >
    >
    > On Tue, 25 Feb 2020 14:30:03 -0800 Shakeel Butt wrote:
    > >
    > > BTW we are seeing a similar situation in our production environment.
    > > We have swappiness=0, no swap from kswapd (because we don't swapout on
    > > pressure, only on cold age) and too few file pages, the kswapd goes
    > > crazy on shrink_slab and spends 100% cpu on it.
    >
    > Dunno if swappiness is able to put peace on your kswapd.
    >
    > --- a/mm/vmscan.c
    > +++ b/mm/vmscan.c
    > @@ -2631,8 +2631,14 @@ static inline bool should_continue_recla
    > */
    > pages_for_compaction = compact_gap(sc->order);
    > inactive_lru_pages = node_page_state(pgdat, NR_INACTIVE_FILE);
    > - if (get_nr_swap_pages() > 0)
    > - inactive_lru_pages += node_page_state(pgdat, NR_INACTIVE_ANON);
    > + do {
    > + struct lruvec *lruvec = mem_cgroup_lruvec(sc->target_mem_cgroup, pgdat);
    > + struct mem_cgroup *memcg = lruvec_memcg(lruvec);
    > + int swappiness = mem_cgroup_swappiness(memcg);
    > +
    > + if (swappiness && get_nr_swap_pages() > 0)

    Thanks for finding this. I think we also need to check sc->may_swap as
    well. Can you please send a signed-off patch? It may or maynot help
    kswapd but I think this is needed.

    > + inactive_lru_pages += node_page_state(pgdat, NR_INACTIVE_ANON);
    > + } while (0);
    >
    > return inactive_lru_pages > pages_for_compaction;
    > }
    >

    \
     
     \ /
      Last update: 2020-02-26 18:05    [W:2.788 / U:0.556 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site