From: Alex,Shi Date: Tue, 1 Nov 2011 00:08:45 +0000 (-0700) Subject: kswapd: assign new_order and new_classzone_idx after wakeup in sleeping X-Git-Tag: v3.2-rc1~108^2~82 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f0dfcde099453aa4c0dc42473828d15a6d492936;p=pandora-kernel.git kswapd: assign new_order and new_classzone_idx after wakeup in sleeping There 2 places to read pgdat in kswapd. One is return from a successful balance, another is waked up from kswapd sleeping. The new_order and new_classzone_idx represent the balance input order and classzone_idx. But current new_order and new_classzone_idx are not assigned after kswapd_try_to_sleep(), that will cause a bug in the following scenario. 1: after a successful balance, kswapd goes to sleep, and new_order = 0; new_classzone_idx = __MAX_NR_ZONES - 1; 2: kswapd waked up with order = 3 and classzone_idx = ZONE_NORMAL 3: in the balance_pgdat() running, a new balance wakeup happened with order = 5, and classzone_idx = ZONE_NORMAL 4: the first wakeup(order = 3) finished successufly, return order = 3 but, the new_order is still 0, so, this balancing will be treated as a failed balance. And then the second tighter balancing will be missed. So, to avoid the above problem, the new_order and new_classzone_idx need to be assigned for later successful comparison. Signed-off-by: Alex Shi Acked-by: Mel Gorman Reviewed-by: Minchan Kim Tested-by: Pádraig Brady Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed