On Tue, Oct 19, 2010 at 12:05 PM, Wu Fengguang <fengguang.wu@xxxxxxxxx> wrote:
> On Tue, Oct 19, 2010 at 10:52:47AM +0800, Minchan Kim wrote:
>> Hi Wu,
>>
>> On Tue, Oct 19, 2010 at 11:35 AM, Wu Fengguang <fengguang.wu@xxxxxxxxx> wrote:
>> >> @@ -2054,10 +2069,11 @@ rebalance:
>> >> goto got_pg;
>> >>
>> >> /*
>> >> - * If we failed to make any progress reclaiming, then we are
>> >> - * running out of options and have to consider going OOM
>> >> + * If we failed to make any progress reclaiming and there aren't
>> >> + * many parallel reclaiming, then we are unning out of options and
>> >> + * have to consider going OOM
>> >> */
>> >> - if (!did_some_progress) {
>> >> + if (!did_some_progress && !too_many_isolated_zone(preferred_zone)) {
>> >> if ((gfp_mask & __GFP_FS) && !(gfp_mask & __GFP_NORETRY)) {
>> >> if (oom_killer_disabled)
>> >> goto nopage;
>> >
>> > This is simply wrong.
>> >
>> > It disabled this block for 99% system because there won't be enough
>> > tasks to make (!too_many_isolated_zone == true). As a result the LRU
>> > will be scanned like mad and no task get OOMed when it should be.
>>
>> If !too_many_isolated_zone is false, it means there are already many
>> direct reclaiming tasks.
>> So they could exit reclaim path and !too_many_isolated_zone will be true