Commit 2da9f630 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Linus Torvalds
Browse files

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 730ec8c0
("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]

Fixes: 730ec8c0 ("mm/vmscan.c: change prototype for shrink_page_list")
Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Acked-by: default avatarMichal 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>
Link: https://lkml.kernel.org/r/20201029032320.1448441-1-npiggin@gmail.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d20bdd57

mm/vmscan.c

+3 −2
Original line number Diff line number Diff line
@@ -1516,7 +1516,8 @@ 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
@@ -1526,7 +1527,7 @@ unsigned int reclaim_clean_pages_from_list(struct zone *zone, 
	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;

}