Hi Mike, On 2/14/2018 10:12 AM, Mike Kravetz wrote: > On 02/13/2018 07:46 AM, Reinette Chatre wrote: >> Adding MM maintainers to v2 to share the new MM change (patch 21/22) that >> enables large contiguous regions that was created to support large Cache >> Pseudo-Locked regions (patch 22/22). This week MM team received another >> proposal to support large contiguous allocations ("[RFC PATCH 0/3] >> Interface for higher order contiguous allocations" at >> http://lkml.kernel.org/r/20180212222056.9735-1-mike.kravetz@xxxxxxxxxx). >> I have not yet tested with this new proposal but it does seem appropriate >> and I should be able to rework patch 22 from this series on top of that if >> it is accepted instead of what I have in patch 21 of this series. >> > > Well, I certainly would prefer the adoption and use of a more general > purpose interface rather than exposing alloc_gigantic_page(). > > Both the interface I suggested and alloc_gigantic_page end up calling > alloc_contig_range(). I have not looked at your entire patch series, but > do be aware that in its present form alloc_contig_range will run into > issues if called by two threads simultaneously for the same page range. > Calling alloc_gigantic_page without some form of synchronization will > expose this issue. Currently this is handled by hugetlb_lock for all > users of alloc_gigantic_page. If you simply expose alloc_gigantic_page > without any type of synchronization, you may run into issues. The first > patch in my RFC "mm: make start_isolate_page_range() fail if already > isolated" should handle this situation IF we decide to expose > alloc_gigantic_page (which I do not suggest). My work depends on the ability to create large contiguous regions, creating these large regions is not the goal in itself. Certainly I would want to use the most appropriate mechanism and I would gladly modify my work to do so. I do not insist on using alloc_gigantic_page(). Now that I am aware of your RFC I started the process to convert to the new find_alloc_contig_pages(). I did not do so earlier because it was not available when I prepared this work for submission. I plan to respond to your RFC when my testing is complete but please give me a few days to do so. Could you please also cc me if you do send out any new versions? Thank you very much! Reinette -- 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>