Messages in this thread | | | Date | Tue, 19 Oct 2010 12:09:29 +0900 | Subject | Re: Deadlock possibly caused by too_many_isolated. | From | Minchan Kim <> |
| |
On Tue, Oct 19, 2010 at 12:05 PM, Wu Fengguang <fengguang.wu@intel.com> 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@intel.com> 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. >> What am I missing now? > > Ah sorry, my brain get short circuited.. but I still feel uneasy with > this change. It's not fixing the root cause and won't prevent too many > LRU pages be isolated. It's too late to test too_many_isolated_zone() > after direct reclaim returns (after sleeping for a long time). >
Intend to agree. I think root cause is a infinite looping in too_many_isolated holding FS lock. Would it be simple that too_many_isolated would be bail out after some try?
> Thanks, > Fengguang >
-- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |