On Thu, Dec 9, 2010 at 8:18 PM, Mel Gorman <mel@xxxxxxxxx> wrote: > When kswapd is woken up for a high-order allocation, it takes account of > the highest usable zone by the caller (the classzone idx). During > allocation, this index is used to select the lowmem_reserve[] that > should be applied to the watermark calculation in zone_watermark_ok(). > > When balancing a node, kswapd considers the highest unbalanced zone to be the > classzone index. This will always be at least be the callers classzone_idx > and can be higher. However, sleeping_prematurely() always considers the > lowest zone (e.g. ZONE_DMA) to be the classzone index. This means that > sleeping_prematurely() can consider a zone to be balanced that is unusable > by the allocation request that originally woke kswapd. This patch changes > sleeping_prematurely() to use a classzone_idx matching the value it used > in balance_pgdat(). > > Signed-off-by: Mel Gorman <mel@xxxxxxxxx> Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx> Nice catch! and it does make sense to me. -- Kind regards, Minchan Kim -- 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 policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>