Free Video Kernel Samepage Merging At Meta And Future Improvements This article describes how linux kernel samepage merging (ksm) has changed. kernel samepage merging has changed over the last couple of versions. this document provides an overview of the changes by version. the document will be updated as new kernel versions become available. optimization for fast changing pages. Ksm was originally developed for use with kvm (where it was known as kernel shared memory), to fit more virtual machines into physical memory, by sharing the data common between them. but it can be useful to any application which generates many instances of the same data.
V Kompany S Blog Ksm Kernel Samepage Merging In the kernel summit track at the 2023 linux plumbers conference (lpc), stefan roesch led a session on kernel samepage merging (ksm). he gave an overview of the feature and described some recent changes to ksm. Since the contents of the pages may change at any moment, ksm cannot just insert the pages into a normal sorted tree and expect it to find anything. therefore ksm uses two data structures the stable and the unstable tree. Ksm only merges anonymous (private) pages, never pagecache (file) pages. ksm’s merged pages were originally locked into kernel memory, but can now be swapped out just like other user pages (but sharing is broken when they are swapped back in: ksmd must rediscover their identity and merge again). While not directly linked, kernel based virtual machine (kvm) can use ksm to merge memory pages occupied by virtual machines.
V Kompany S Blog Ksm Kernel Samepage Merging Ksm only merges anonymous (private) pages, never pagecache (file) pages. ksm’s merged pages were originally locked into kernel memory, but can now be swapped out just like other user pages (but sharing is broken when they are swapped back in: ksmd must rediscover their identity and merge again). While not directly linked, kernel based virtual machine (kvm) can use ksm to merge memory pages occupied by virtual machines. Kernel same page merging (ksm), used by the kvm hypervisor, allows kvm guests to share identical memory pages. these shared pages are usually common libraries or other identical, high use data. What is kernel samepage merging (ksm)? kernel samepage merging is a memory de duplicating scheme that finds duplicate anonymous memory pages and shares them in order to alleviate memory bottlenecks. The project consists of developing code to test the performance of the memory saving feature kernel samepage merging (ksm) when using huge pages. these tests are called kselftests, and are contained in the kernel tree.
V Kompany S Blog Ksm Kernel Samepage Merging Kernel same page merging (ksm), used by the kvm hypervisor, allows kvm guests to share identical memory pages. these shared pages are usually common libraries or other identical, high use data. What is kernel samepage merging (ksm)? kernel samepage merging is a memory de duplicating scheme that finds duplicate anonymous memory pages and shares them in order to alleviate memory bottlenecks. The project consists of developing code to test the performance of the memory saving feature kernel samepage merging (ksm) when using huge pages. these tests are called kselftests, and are contained in the kernel tree.
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