Huge Page Support: Difference between revisions
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== What Are Huge Pages? == |
== What Are Huge Pages? == |
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DirectMap4k: 1056768 kB |
DirectMap4k: 1056768 kB |
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DirectMap2M: 0 kB |
DirectMap2M: 0 kB |
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=== References === |
=== References === |
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Revision as of 13:51, 7 May 2015
What Are Huge Pages?
- Huge pages are also known as 'superpages' in FreeBSD (or 'large pages' in the Microsoft Windows world)
- Newer AMD64 processors can use 1GB pages in long mode.
- Linux has supported huge pages on several architectures since the 2.6 series via the hugetlbfs filesystem.
- Xen Project supports allocating huge pages for HVM and PVH guests (use in PV guests is not supported). The hypervisor itself uses huge pages wherever it can.
Using Huge Pages
- Specify the hypervisor boot command line flag `allowsuperpage` (it was called `allowhugepage` before).
- Specify the Linux boot command line flag `balloon_hugepages`.
- In the guest::
# echo 20 > /proc/sys/vm/nr_hugepages # cat /proc/meminfo ... AnonHugePages: 0 kB HugePages_Total: 20 HugePages_Free: 20 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB DirectMap4k: 1056768 kB DirectMap2M: 0 kB
References
- Wikipedia entry for Huge Pages
- Huge Pages from Linux memory management site
- Huge Page Document from Kernel.org
- And the source document for this page: http://zhigang.org/wiki/XenHugePages
