Document URL: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html-single/monitoring_and_managing_system_status_and_performance/index#parameters-for-reserving-hugetlb-pages-at-boot-time_configuring-huge-pages https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html-single/monitoring_and_managing_system_status_and_performance/index#configuring-hugetlb-at-boot-time_configuring-huge-pages Section Number and Name: 36.2. Parameters for reserving HugeTLB pages at boot time 36.3. Configuring HugeTLB at boot time Describe the issue: The note in Section 36.3 says "The most reliable way to reserve 1 GB pages is by using this hugetlb-reserve-pages.sh script, which runs early during boot." However, section 36.2 just above describes how to reserve huge pages through the kernel cmdline, which should be even even more reliable as it is applied even earlier in the boot process than any systemd controlled script is . Additionally, the upstream kernel docs https://docs.kernel.org/admin-guide/mm/hugetlbpage.html mentions "The administrator can allocate persistent huge pages on the kernel boot command line by specifying the "hugepages=N" parameter, where 'N' = the number of huge pages requested. This is the most reliable method of allocating huge pages as memory has not yet become fragmented." which seems to contradict the note about hugetlb-reserve-pages.sh in section 36.3 Suggestions for improvement: Either clarify/explain why hugetlb-reserve-pages.sh should be regarded as the most reliable method or align RH docs with upstream kernel docs Additional information: RHEL9 docs contain the same guidance about using hugetlb-reserve-pages.sh https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html-single/monitoring_and_managing_system_status_and_performance/index#configuring-hugetlb-at-boot-time_configuring-huge-pages RHEL7 docs contain the same guidance about using hugetlb-reserve-pages.sh https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html-single/performance_tuning_guide/index#sect-Red_Hat_Enterprise_Linux-Performance_Tuning_Guide-Memory-Configuring-huge-pages
Hi, thanks for the report. I'll get to work on it!
Updates published at: RHEL7: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html-single/performance_tuning_guide/index#sect-Red_Hat_Enterprise_Linux-Performance_Tuning_Guide-Memory-Configuring-huge-pages RHEL8: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/monitoring_and_managing_system_status_and_performance/configuring-huge-pages_monitoring-and-managing-system-status-and-performance#configuring-hugetlb-at-boot-time_configuring-huge-pages RHEL9: https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/monitoring_and_managing_system_status_and_performance/configuring-huge-pages_monitoring-and-managing-system-status-and-performance#configuring-hugetlb-at-boot-time_configuring-huge-pages Moving to closed, thanks for the report