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. 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! -- Mike Kravetz
