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Who	When	What	Removed	Added
Red Hat Bugzilla	2021-05-11 08:52:15 UTC	Pool ID		sst_ccs_rhel_8
Red Hat One Jira (issues.redhat.com)	2021-05-11 08:53:18 UTC	Link ID		Red Hat Issue Tracker RHELPLAN-78756
Tomas Capek	2021-05-11 09:25:25 UTC	Keywords		Documentation
		Priority	unspecified	high
		Assignee	rhel-docs	lkuprova
Lenka Špačková	2021-05-12 12:37:35 UTC	CC		jklech, lkuprova
		Assignee	lkuprova	jklech
		Flags		needinfo?(jklech)
Jaroslav Klech	2021-06-08 08:09:03 UTC	CC		llong
		Flags	needinfo?(jklech)	needinfo?(llong)
Jaroslav Klech	2021-06-08 08:10:30 UTC	Status	NEW	ASSIGNED
Waiman Long	2021-06-08 14:38:10 UTC	Flags	needinfo?(llong)
Jaroslav Klech	2021-06-08 17:09:07 UTC	Doc Text		With the extended address range, the memory management in Red Hat Enterprise Linux 8 adds support for 5-level page table implementation, to be able to handle the expanded address range. The 5-level page table is enabled for hardware capable of supporting this feature. You can use the `no5lvl` kernel command-line parameter to disable the 5-level paging on the eligible systems. Also, users should use `no5lvl` to disable 5-level page table if their installed memory does not exceed the limit imposed by 4-level page table to avoid the additional page table walking overhead.
		Flags		needinfo?(llong)
Waiman Long	2021-06-08 17:19:38 UTC	Flags	needinfo?(llong)
Jaroslav Klech	2021-06-09 07:12:55 UTC	Doc Text	With the extended address range, the memory management in Red Hat Enterprise Linux 8 adds support for 5-level page table implementation, to be able to handle the expanded address range. The 5-level page table is enabled for hardware capable of supporting this feature. You can use the `no5lvl` kernel command-line parameter to disable the 5-level paging on the eligible systems. Also, users should use `no5lvl` to disable 5-level page table if their installed memory does not exceed the limit imposed by 4-level page table to avoid the additional page table walking overhead.	With the extended address range, the memory management in Red Hat Enterprise Linux 8 adds support for 5-level page table implementation. This implementation is able to handle the expanded address range. The 5-level page table is enabled for hardware capable of supporting this feature. You can use the `no5lvl` kernel command-line parameter to disable the 5-level paging on the eligible systems. To avoid additional page table walk overhead, users should disable 5-level page table if their installed memory does not exceed the limit imposed by 4-level page table.
		Flags		needinfo?(llong)
Waiman Long	2021-06-09 14:29:20 UTC	Flags	needinfo?(llong)
Jaroslav Klech	2021-06-10 08:18:55 UTC	Doc Text	With the extended address range, the memory management in Red Hat Enterprise Linux 8 adds support for 5-level page table implementation. This implementation is able to handle the expanded address range. The 5-level page table is enabled for hardware capable of supporting this feature. You can use the `no5lvl` kernel command-line parameter to disable the 5-level paging on the eligible systems. To avoid additional page table walk overhead, users should disable 5-level page table if their installed memory does not exceed the limit imposed by 4-level page table.	.5-level page tables x86_64 With Red Hat Enterprise Linux 7, existing memory bus had 48/46 bit of virtual/physical memory addressing capacity, and the Linux kernel implemented 4 levels of page tables to manage these virtual addresses to physical addresses. The physical bus addressing line put the physical memory upper limit capacity at 64 TB. These limits have been extended to 57/52 bit of virtual/physical memory addressing with 128 PiB of virtual address space (64PB user/64PB kernel) and 4 PB of physical memory capacity. With the extended address range, the memory management in Red Hat Enterprise Linux 8 adds support for 5-level page table implementation. This implementation is able to handle the expanded address range with up to 128 PiB of virtual address space and 4 PiB of physical address space. The 5-level page table is enabled by default for hardware capable of supporting this feature even if the installed physical memory is less than 64 TiB. For systems with less than 64 TiB of memory, there is a small overhead increase in walking the 5-level page table. To avoid this overhead, users can disable 5-level page table with the `no5lvl` kernel command-line parameter to force the use of 4-level page table.
Jaroslav Klech	2021-06-10 14:10:10 UTC	Doc Text	.5-level page tables x86_64 With Red Hat Enterprise Linux 7, existing memory bus had 48/46 bit of virtual/physical memory addressing capacity, and the Linux kernel implemented 4 levels of page tables to manage these virtual addresses to physical addresses. The physical bus addressing line put the physical memory upper limit capacity at 64 TB. These limits have been extended to 57/52 bit of virtual/physical memory addressing with 128 PiB of virtual address space (64PB user/64PB kernel) and 4 PB of physical memory capacity. With the extended address range, the memory management in Red Hat Enterprise Linux 8 adds support for 5-level page table implementation. This implementation is able to handle the expanded address range with up to 128 PiB of virtual address space and 4 PiB of physical address space. The 5-level page table is enabled by default for hardware capable of supporting this feature even if the installed physical memory is less than 64 TiB. For systems with less than 64 TiB of memory, there is a small overhead increase in walking the 5-level page table. To avoid this overhead, users can disable 5-level page table with the `no5lvl` kernel command-line parameter to force the use of 4-level page table.	.5-level page tables x86_64 In Red Hat Enterprise Linux 7, existing memory bus had 48/46 bit of virtual/physical memory addressing capacity, and the Linux kernel implemented 4 levels of page tables to manage these virtual addresses to physical addresses. The physical bus addressing line put the physical memory upper limit capacity at 64 TB. These limits have been extended to 57/52 bit of virtual/physical memory addressing with 128 PiB of virtual address space (64PB user/64PB kernel) and 4 PB of physical memory capacity. With the extended address range, the memory management in Red Hat Enterprise Linux 8 adds support for 5-level page table implementation. This implementation is able to handle the expanded address range with up to 128 PiB of virtual address space and 4 PiB of physical address space. The 5-level page table is enabled by default for hardware capable of supporting this feature even if the installed physical memory is less than 64 TiB. For systems with less than 64 TiB of memory, there is a small overhead increase in walking the 5-level page table. To avoid this overhead, users can disable 5-level page table by using the `no5lvl` kernel command-line parameter to force the use of 4-level page table.
Jaroslav Klech	2021-06-10 14:12:03 UTC	Flags		needinfo?(lkuprova)
Jaroslav Klech	2021-06-10 14:12:22 UTC	Status	ASSIGNED	VERIFIED
Lenka Špačková	2021-06-10 16:19:10 UTC	Flags	needinfo?(lkuprova)	needinfo?(jklech)
Jaroslav Klech	2021-06-14 08:59:10 UTC	Status	VERIFIED	CLOSED
		Resolution	---	CURRENTRELEASE
		Flags	needinfo?(jklech)
		Last Closed		2021-06-14 08:59:10 UTC
Jaroslav Klech	2021-06-14 09:00:33 UTC	Doc Text	.5-level page tables x86_64 In Red Hat Enterprise Linux 7, existing memory bus had 48/46 bit of virtual/physical memory addressing capacity, and the Linux kernel implemented 4 levels of page tables to manage these virtual addresses to physical addresses. The physical bus addressing line put the physical memory upper limit capacity at 64 TB. These limits have been extended to 57/52 bit of virtual/physical memory addressing with 128 PiB of virtual address space (64PB user/64PB kernel) and 4 PB of physical memory capacity. With the extended address range, the memory management in Red Hat Enterprise Linux 8 adds support for 5-level page table implementation. This implementation is able to handle the expanded address range with up to 128 PiB of virtual address space and 4 PiB of physical address space. The 5-level page table is enabled by default for hardware capable of supporting this feature even if the installed physical memory is less than 64 TiB. For systems with less than 64 TiB of memory, there is a small overhead increase in walking the 5-level page table. To avoid this overhead, users can disable 5-level page table by using the `no5lvl` kernel command-line parameter to force the use of 4-level page table.

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