On Tue, Sep 26, 2017 at 04:46:42PM +0800, Hui Zhu wrote: > Current HighAtomic just to handle the high atomic page alloc. > But I found that use it handle the normal unmovable continuous page > alloc will help to against long-term fragmentation. > This is not wise. High-order atomic allocations do not always have a smooth recovery path such as network drivers with large MTUs that have no choice but to drop the traffic and hope for a retransmit. That's why they have the highatomic reserve. If the reserve is used for normal unmovable allocations then allocation requests that could have waited for reclaim may cause high-order atomic allocations to fail. Changing it may allow improve latencies in some limited cases while causing functional failures in others. If there is a special case where there are a large number of other high-order allocations then I would suggest increasing min_free_kbytes instead as a workaround. -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
