tmem has TMEM_HASH_BUCKETS (256) buckets per pool. However, because of the way the tmem_oid is generated for frontswap pages, only 16 unique tmem_oids are being generated, resulting in only 16 of the 256 buckets being used. This cause high lock contention for the per bucket locks. This patch changes SWIZ_BITS to include more bits of the offset. The result is that all 256 hash buckets are potentially used resulting in a 95% drop in hash bucket lock contention. Signed-off-by: Seth Jennings Acked-by: Dan Magenheimer Signed-off-by: Greg Kroah-Hartman ËfUê›'x