On Wed, 13 Apr 2022 22:47:48 +0800 Muchun Song <songmuchun@xxxxxxxxxxxxx> wrote: > We must add hugetlb_free_vmemmap=on (or "off") to the boot cmdline and > reboot the server to enable or disable the feature of optimizing vmemmap > pages associated with HugeTLB pages. However, rebooting usually takes a > long time. So add a sysctl to enable or disable the feature at runtime > without rebooting. Do we really need this feature? Really? What's the use case and what is the end-user value? Presumably CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP worsens things for some setups/workloads? Please tell us much more about that. What is the magnitude of the deoptimization?
