On Mon, 21 Feb 2011, Dave Hansen wrote: > > v2 - rework if() block, and remove now redundant split_huge_page() > > Right now, if a mm_walk has either ->pte_entry or ->pmd_entry > set, it will unconditionally split any transparent huge pages > it runs in to. In practice, that means that anyone doing a > > cat /proc/$pid/smaps > > will unconditionally break down every huge page in the process > and depend on khugepaged to re-collapse it later. This is > fairly suboptimal. > > This patch changes that behavior. It teaches each ->pmd_entry > handler (there are five) that they must break down the THPs > themselves. Also, the _generic_ code will never break down > a THP unless a ->pte_entry handler is actually set. > > This means that the ->pmd_entry handlers can now choose to > deal with THPs without breaking them down. > > Acked-by: Mel Gorman <mel@xxxxxxxxx> > Signed-off-by: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx> Acked-by: David Rientjes <rientjes@xxxxxxxxxx> Thanks for adding the comment about ->pmd_entry() being required to split the pages in include/linux/mm.h! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>