On Thu, 29 Oct 2020 14:11:03 +0100 Michal Hocko <mhocko@xxxxxxxx> wrote:
> On Thu 29-10-20 13:23:20, Nicholas Piggin wrote:
> > Previously the negated unsigned long would be cast back to signed long
> > which would have the correct negative value. After commit 730ec8c01a2b
> > ("mm/vmscan.c: change prototype for shrink_page_list"), the large
> > unsigned int converts to a large positive signed long.
> >
> > Symptoms include CMA allocations hanging forever holding the cma_mutex
> > due to alloc_contig_range->...->isolate_migratepages_block waiting
> > forever in "while (unlikely(too_many_isolated(pgdat)))".
>
> Nasty.
>
> > Cc: linux-mm@xxxxxxxxx
> > Cc: Maninder Singh <maninder1.s@xxxxxxxxxxx>
> > Cc: Vaneet Narang <v.narang@xxxxxxxxxxx>
> > Cc: Maninder Singh <maninder1.s@xxxxxxxxxxx>
> > Cc: Michal Hocko <mhocko@xxxxxxxx>
> > Cc: Amit Sahrawat <a.sahrawat@xxxxxxxxxxx>
> > Cc: Mel Gorman <mgorman@xxxxxxx>
> > Cc: Vlastimil Babka <vbabka@xxxxxxx>
> > Fixes: 730ec8c01a2b ("mm/vmscan.c: change prototype for shrink_page_list")
> > Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
> > ---
> > mm/vmscan.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/mm/vmscan.c b/mm/vmscan.c
> > index 1b8f0e059767..92c507bacf09 100644
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -1516,7 +1516,7 @@ unsigned int reclaim_clean_pages_from_list(struct zone *zone,
> > nr_reclaimed = shrink_page_list(&clean_pages, zone->zone_pgdat, &sc,
> > TTU_IGNORE_ACCESS, &stat, true);
> > list_splice(&clean_pages, page_list);
> > - mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE, -nr_reclaimed);
> > + mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE, -(long)nr_reclaimed);
> > /*
> > * Since lazyfree pages are isolated from file LRU from the beginning,
> > * they will rotate back to anonymous LRU in the end if it failed to
>
> You want the same also for -stat.nr_lazyfree_fail right?
I did the below, and added a cc:stable.
--- a/mm/vmscan.c~mm-vmscan-fix-nr_isolated_file-corruption-on-64-bit-fix
+++ a/mm/vmscan.c
@@ -1516,7 +1516,8 @@ unsigned int reclaim_clean_pages_from_li
nr_reclaimed = shrink_page_list(&clean_pages, zone->zone_pgdat, &sc,
TTU_IGNORE_ACCESS, &stat, true);
list_splice(&clean_pages, page_list);
- mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE, -(long)nr_reclaimed);
+ mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE,
+ -(long)nr_reclaimed);
/*
* Since lazyfree pages are isolated from file LRU from the beginning,
* they will rotate back to anonymous LRU in the end if it failed to
@@ -1526,7 +1527,7 @@ unsigned int reclaim_clean_pages_from_li
mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_ANON,
stat.nr_lazyfree_fail);
mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE,
- -stat.nr_lazyfree_fail);
+ -(long)stat.nr_lazyfree_fail);
return nr_reclaimed;
}
_
