From: Nicholas Piggin npiggin@gmail.com Subject: mm/vmscan: fix NR_ISOLATED_FILE corruption on 64-bit
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)))".
[akpm@linux-foundation.org: fix -stat.nr_lazyfree_fail as well, per Michal] Link: https://lkml.kernel.org/r/20201029032320.1448441-1-npiggin@gmail.com Fixes: 730ec8c01a2b ("mm/vmscan.c: change prototype for shrink_page_list") Signed-off-by: Nicholas Piggin npiggin@gmail.com Acked-by: Michal Hocko mhocko@suse.com Cc: Vaneet Narang v.narang@samsung.com Cc: Maninder Singh maninder1.s@samsung.com Cc: Amit Sahrawat a.sahrawat@samsung.com Cc: Mel Gorman mgorman@suse.de Cc: Vlastimil Babka vbabka@suse.cz Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
mm/vmscan.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
--- a/mm/vmscan.c~mm-vmscan-fix-nr_isolated_file-corruption-on-64-bit +++ 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, -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; }
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