On 6/5/19 1:30 AM, Mike Kravetz wrote:
> While looking at some really long hugetlb page allocation times, I noticed
> instances where should_compact_retry() was returning true more often that
> I expected. In one allocation attempt, it returned true 765668 times in a
> row. To me, this was unexpected because of the following:
>
> #define MAX_COMPACT_RETRIES 16
> int max_retries = MAX_COMPACT_RETRIES;
>
> However, if should_compact_retry() returns true via the following path we
> do not increase the retry count.
>
> /*
> * make sure the compaction wasn't deferred or didn't bail out early
> * due to locks contention before we declare that we should give up.
> * But do not retry if the given zonelist is not suitable for
> * compaction.
> */
> if (compaction_withdrawn(compact_result)) {
> ret = compaction_zonelist_suitable(ac, order, alloc_flags);
> goto out;
> }
>
> Just curious, is this intentional?
Hmm I guess we didn't expect compaction_withdrawn() to be so
consistently returned. Do you know what value of compact_result is there
in your test?
