On Wed, Mar 06, 2019 at 06:15:25PM +0530, Aneesh Kumar K.V wrote: > On 3/6/19 5:14 PM, Michal Suchánek wrote: > > On Wed, 06 Mar 2019 14:47:33 +0530 > > "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> wrote: > > > > > Dan Williams <dan.j.williams@xxxxxxxxx> writes: > > > > > > > On Thu, Feb 28, 2019 at 1:40 AM Oliver <oohall@xxxxxxxxx> wrote: > > > > > > > > > > On Thu, Feb 28, 2019 at 7:35 PM Aneesh Kumar K.V > > > > > <aneesh.kumar@xxxxxxxxxxxxx> wrote: > > > Also even if the user decided to not use THP, by > > > echo "never" > transparent_hugepage/enabled , we should continue to map > > > dax fault using huge page on platforms that can support huge pages. > > > > Is this a good idea? > > > > This knob is there for a reason. In some situations having huge pages > > can severely impact performance of the system (due to host-guest > > interaction or whatever) and the ability to really turn off all THP > > would be important in those cases, right? > > > > My understanding was that is not true for dax pages? These are not regular > memory that got allocated. They are allocated out of /dev/dax/ or > /dev/pmem*. Do we have a reason not to use hugepages for mapping pages in > that case? Yes. Like when you don't want dax to compete for TLB with mission-critical application (which uses hugetlb for instance). -- Kirill A. Shutemov
