> -----Original Message----- > From: Minchan Kim [mailto:minchan.kim@xxxxxxxxx] > Sent: Friday, July 29, 2011 4:57 PM > To: Shi, Alex > Cc: majordomo@xxxxxxxxx; P@xxxxxxxxxxxxxx; mgorman@xxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; andrea@xxxxxxxxxxxx; Chen, Tim C; Li, > Shaohua; akpm@xxxxxxxxxxxxxxxxxxxx; riel@xxxxxxxxxx; luto@xxxxxxx > Subject: Re: [PATCH] kswapd: assign new_order and new_classzone_idx after > wakeup in sleeping > > On Fri, Jul 29, 2011 at 09:34:42AM +0800, Alex Shi wrote: > > There 2 place to read pgdat in kswapd. One is return from a successful > > balance, another is waked up from sleeping. But the new_order and > > new_classzone_idx are not assigned after kswapd_try_to_sleep(), that > > will cause a bug in the following scenario. > > > > After the last time successful balance, kswapd goes to sleep. So the > > new_order and new_classzone_idx were assigned to 0 and MAX-1 since there > > is no new wakeup during last time balancing. Now, a new wakeup came and > > finish balancing successful with order > 0. But since new_order is still > > 0, this time successful balancing were judged as a failed balance. so, > > if there is another new wakeup coming during balancing, kswapd cann't > > read this and still want to try to sleep. And if the new wakeup is a > > tighter request, kswapd may goes to sleep, not to do balancing. That is > > incorrect. > > > > So, to avoid above problem, the new_order and new_classzone_idx need to > > be assigned for later successful comparison. > > > > Paidrag Brady, Could like do a retry for your problem on this patch? > > > > Signed-off-by: Alex Shi <alex.shi@xxxxxxxxx> > > Acked-by: Mel Gorman <mgorman@xxxxxxx> > Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx> Thanks for review. BTW, I remove the incorrect email address of linux-mm. sorry for this! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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