Re: [PATCH RFC 2/2] mm, hugetlb: do not rely on overcommit limit during migration

[Michal Hocko]

On Wed 29-11-17 10:22:34, Michal Hocko wrote:
> What about this on top. I haven't tested this yet though.

OK, it seem to work:
root@test1:~# echo 1 > /proc/sys/vm/nr_hugepages
root@test1:~# echo 1 > /sys/kernel/mm/hugepages/hugepages-2048kB/nr_overcommit_hugepages

root@test1:~# grep . /sys/devices/system/node/node*/hugepages/hugepages-2048kB/*
/sys/devices/system/node/node0/hugepages/hugepages-2048kB/free_hugepages:0
/sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages:0
/sys/devices/system/node/node0/hugepages/hugepages-2048kB/surplus_hugepages:0
/sys/devices/system/node/node1/hugepages/hugepages-2048kB/free_hugepages:1
/sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages:1
/sys/devices/system/node/node1/hugepages/hugepages-2048kB/surplus_hugepages:0

# mmap 2 huge pages

root@test1:~# grep . /sys/devices/system/node/node*/hugepages/hugepages-2048kB/*
/sys/devices/system/node/node0/hugepages/hugepages-2048kB/free_hugepages:0
/sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages:0
/sys/devices/system/node/node0/hugepages/hugepages-2048kB/surplus_hugepages:0
/sys/devices/system/node/node1/hugepages/hugepages-2048kB/free_hugepages:0
/sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages:2
/sys/devices/system/node/node1/hugepages/hugepages-2048kB/surplus_hugepages:1

root@test1:~# migratepages $(pidof map_hugetlb) 1 0

/sys/devices/system/node/node0/hugepages/hugepages-2048kB/free_hugepages:0
/sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages:2
/sys/devices/system/node/node0/hugepages/hugepages-2048kB/surplus_hugepages:1
/sys/devices/system/node/node1/hugepages/hugepages-2048kB/free_hugepages:0
/sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages:0
/sys/devices/system/node/node1/hugepages/hugepages-2048kB/surplus_hugepages:0

and exit the mmap

root@test1:~# grep . /sys/devices/system/node/node*/hugepages/hugepages-2048kB/*
/sys/devices/system/node/node0/hugepages/hugepages-2048kB/free_hugepages:1
/sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages:1
/sys/devices/system/node/node0/hugepages/hugepages-2048kB/surplus_hugepages:0
/sys/devices/system/node/node1/hugepages/hugepages-2048kB/free_hugepages:0
/sys/devices/system/node/node1/hugepages/hugepages-2048kB/nr_hugepages:0
/sys/devices/system/node/node1/hugepages/hugepages-2048kB/surplus_hugepages:0
-- 
Michal Hocko
SUSE Labs