From: Rik van Riel <riel@xxxxxxxxxxx> Subject: mm,shmem,thp: limit shmem THP allocations to requested zones Hugh pointed out that the gma500 driver uses shmem pages, but needs to limit them to the DMA32 zone. Ensure the allocations resulting from the gfp_mask returned by limit_gfp_mask use the zone flags that were originally passed to shmem_getpage_gfp. Link: https://lkml.kernel.org/r/20210224121016.1314ed6d@xxxxxxxxxxxxxxxxxxxx Signed-off-by: Rik van Riel <riel@xxxxxxxxxxx> Suggested-by: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Cc: Xu Yu <xuyu@xxxxxxxxxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxx> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/shmem.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/mm/shmem.c~mmshmemthp-limit-shmem-thp-allocations-to-requested-zones +++ a/mm/shmem.c @@ -1513,7 +1513,11 @@ static gfp_t limit_gfp_mask(gfp_t huge_g { gfp_t allowflags = __GFP_IO | __GFP_FS | __GFP_RECLAIM; gfp_t denyflags = __GFP_NOWARN | __GFP_NORETRY; - gfp_t result = huge_gfp & ~allowflags; + gfp_t zoneflags = limit_gfp & GFP_ZONEMASK; + gfp_t result = huge_gfp & ~(allowflags | GFP_ZONEMASK); + + /* Allow allocations only from the originally specified zones. */ + result |= zoneflags; /* * Minimize the result gfp by taking the union with the deny flags, _
