On 7/25/19 7:15 PM, Mike Kravetz wrote: > On 7/25/19 1:13 AM, Mel Gorman wrote: >> On Wed, Jul 24, 2019 at 10:50:14AM -0700, Mike Kravetz wrote: >>> When allocating hugetlbfs pool pages via /proc/sys/vm/nr_hugepages, >>> the pages will be interleaved between all nodes of the system. If >>> nodes are not equal, it is quite possible for one node to fill up >>> before the others. When this happens, the code still attempts to >>> allocate pages from the full node. This results in calls to direct >>> reclaim and compaction which slow things down considerably. >>> >>> When allocating pool pages, note the state of the previous allocation >>> for each node. If previous allocation failed, do not use the >>> aggressive retry algorithm on successive attempts. The allocation >>> will still succeed if there is memory available, but it will not try >>> as hard to free up memory. >>> >>> Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> >> >> set_max_huge_pages can fail the NODEMASK_ALLOC() alloc which you handle >> *but* in the event of an allocation failure this bug can silently recur. >> An informational message might be justified in that case in case the >> stall should recur with no hint as to why. > > Right. > Perhaps a NODEMASK_ALLOC() failure should just result in a quick exit/error. > If we can't allocate a node mask, it is unlikely we will be able to allocate > a/any huge pages. And, the system must be extremely low on memory and there > are likely other bigger issues. Agreed. But I would perhaps drop __GFP_NORETRY from the mask allocation as that can fail for transient conditions. > There have been discussions elsewhere about discontinuing the use of > NODEMASK_ALLOC() and just putting the mask on the stack. That may be > acceptable here as well. > >> Technically passing NULL into >> NODEMASK_FREE is also safe as kfree (if used for that kernel config) can >> handle freeing of a NULL pointer. However, that is cosmetic more than >> anything. Whether you decide to change either or not; > > Yes. > I will clean up with an updated series after more feedback. > >> >> Acked-by: Mel Gorman <mgorman@xxxxxxx> >> > > Thanks! >
