On 8/1/19 10:33 PM, Mike Kravetz wrote: > On 8/1/19 6:01 AM, Vlastimil Babka wrote: >> Could you try testing the patch below instead? It should hopefully >> eliminate the stalls. If it makes hugepage allocation give up too early, >> we'll know we have to involve __GFP_RETRY_MAYFAIL in allowing the >> MIN_COMPACT_PRIORITY priority. Thanks! > > Thanks. This patch does eliminate the stalls I was seeing. Great, thanks! I'll send a proper patch then. > In my testing, there is little difference in how many hugetlb pages are > allocated. It does not appear to be giving up/failing too early. But, > this is only with __GFP_RETRY_MAYFAIL. The real concern would with THP > requests. Any suggestions on how to test that? AFAICS the default THP defrag mode is unaffected, as GFP_TRANSHUGE_LIGHT doesn't include __GFP_DIRECT_RECLAIM, so it never reaches this code. Madvised THP allocations will be affected, which should best be tested the same way as Andrea and Mel did in the __GFP_THISNODE debate.
