Huge-page support
Note: Across the IT industry, huge pages and large pages are
used synonymously for memory pages that exceed 4 KB. In keeping with the more commonly used
term in the context of Linux®, this publication uses
huge pages.
Huge-page support entails support for the Linux hugetlbfs file system.
This virtual file system is backed by larger memory pages than the usual 4 K pages; for IBM Z® the hardware page size is 1 MB.
To check whether 1 MB huge pages are supported in your
environment, issue the command:
# grep -o edat /proc/cpuinfo
edatedat as a feature indicates 1 MB huge-page support. Applications that use huge-page memory save a considerable amount of page table memory. Another benefit from the support might be an acceleration in the address translation and overall memory access speed.
You can also configure 2 GB huge pages if Linux is running on an LPAR or as a KVM guest.
Ubuntu Server 22.04 LTS also supports transparent
hugepages. For more information, see the transhuge.txt file, available in the
linux-doc package. You can find it, for example, by issuing the following
command:
# find / -type f -iname "*transhuge*" 2> /dev/null
/usr/share/doc/linux-doc/vm/transhuge.txt.gz