Ping Andi, On Thu, Apr 04, 2013 at 05:09:08PM +0800, Wanpeng Li wrote: >order >= MAX_ORDER pages are only allocated at boot stage using the >bootmem allocator with the "hugepages=xxx" option. These pages are never >free after boot by default since it would be a one-way street(>= MAX_ORDER >pages cannot be allocated later), but if administrator confirm not to >use these gigantic pages any more, these pinned pages will waste memory >since other users can't grab free pages from gigantic hugetlb pool even >if OOM, it's not flexible. The patchset add hugetlb gigantic page pools >shrink supporting. Administrator can enable knob exported in sysctl to >permit to shrink gigantic hugetlb pool. > >Testcase: >boot: hugepagesz=1G hugepages=10 > >[root@localhost hugepages]# free -m > total used free shared buffers cached >Mem: 36269 10836 25432 0 11 288 >-/+ buffers/cache: 10537 25732 >Swap: 35999 0 35999 >[root@localhost hugepages]# echo 0 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages >-bash: echo: write error: Invalid argument >[root@localhost hugepages]# echo 1 > /proc/sys/vm/hugetlb_shrink_gigantic_pool >[root@localhost hugepages]# echo 0 > /sys/kernel/mm/hugepages/hugepages-1048576kB/nr_hugepages >[root@localhost hugepages]# free -m > total used free shared buffers cached >Mem: 36269 597 35672 0 11 288 >-/+ buffers/cache: 297 35972 >Swap: 35999 0 35999 > >Wanpeng Li (6): > introduce new sysctl knob which control gigantic page pools shrinking > update_and_free_page gigantic pages awareness > enable gigantic hugetlb page pools shrinking > use already exist huge_page_order() instead of h->order > remove redundant hugetlb_prefault > use already exist interface huge_page_shift > > Documentation/sysctl/vm.txt | 13 +++++++ > include/linux/hugetlb.h | 5 +-- > kernel/sysctl.c | 7 ++++ > mm/hugetlb.c | 83 +++++++++++++++++++++++++++++-------------- > mm/internal.h | 1 + > mm/page_alloc.c | 2 +- > 6 files changed, 82 insertions(+), 29 deletions(-) > >-- >1.7.10.4 -- 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>