Re: mlock ulimits for SHM_HUGETLB

[Michal Hocko]

Hi,
On Mon 19-05-25 10:21:17, Bharat Agrawal wrote:
> Hi all,
> 
> Could anyone please help comment on the risks associated with an
> application throwing the "Using mlock ulimits for SHM_HUGETLB is
> deprecated" message on RHEL 8.9 with 4.18.0-513.18.1.el8_9.x86_64
> Linux kernel?

This is not RHEL specific behavior. The current Linus tree has the same
warning which has been added by 
: commit 2584e517320bd48dc8d20e38a2621a2dbe58fade
: Author: Ravikiran G Thirumalai <kiran@xxxxxxxxxxxx>
: Date:   Tue Mar 31 15:21:26 2009 -0700
: 
:     mm: reintroduce and deprecate rlimit based access for SHM_HUGETLB
: 
:     Allow non root users with sufficient mlock rlimits to be able to allocate
:     hugetlb backed shm for now.  Deprecate this though.  This is being
:     deprecated because the mlock based rlimit checks for SHM_HUGETLB is not
:     consistent with mmap based huge page allocations.
: 
:     Signed-off-by: Ravikiran Thirumalai <kiran@xxxxxxxxxxxx>
:     Reviewed-by: Mel Gorman <mel@xxxxxxxxx>
:     Cc: William Lee Irwin III <wli@xxxxxxxxxxxxxx>
:     Cc: Adam Litke <agl@xxxxxxxxxx>
:     Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
:     Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>

HTH
-- 
Michal Hocko
SUSE Labs