Commit 75c05fab authored by Mike Rapoport's avatar Mike Rapoport Committed by Jonathan Corbet
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docs/kernel-parameters: update description of mem= 



The existing description of mem= does not cover all the cases and
differences between how architectures treat it.

Extend the description to match the code.

Signed-off-by: default avatarMike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/20220310082736.1346366-1-rppt@kernel.org


Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent c01c2e43

Documentation/admin-guide/kernel-parameters.txt

+18 −0
Original line number Diff line number Diff line
@@ -2827,6 +2827,9 @@ 


			For details see: Documentation/admin-guide/hw-vuln/mds.rst



	mem=nn[KMG]	[HEXAGON] Set the memory size.

			Must be specified, otherwise memory size will be 0.



	mem=nn[KMG]	[KNL,BOOT] Force usage of a specific amount of memory

			Amount of memory to be used in cases as follows:
@@ -2834,6 +2837,13 @@ 
			2 when the kernel is not able to see the whole system memory;

			3 memory that lies after 'mem=' boundary is excluded from

			 the hypervisor, then assigned to KVM guests.

			4 to limit the memory available for kdump kernel.



			[ARC,MICROBLAZE] - the limit applies only to low memory,

			high memory is not affected.



			[ARM64] - only limits memory covered by the linear

			mapping. The NOMAP regions are not affected.



			[X86] Work as limiting max address. Use together

			with memmap= to avoid physical address space collisions.
@@ -2844,6 +2854,14 @@ 
			in above case 3, memory may need be hot added after boot

			if system memory of hypervisor is not sufficient.



	mem=nn[KMG]@ss[KMG]

			[ARM,MIPS] - override the memory layout reported by

			firmware.

			Define a memory region of size nn[KMG] starting at

			ss[KMG].

			Multiple different regions can be specified with

			multiple mem= parameters on the command line.



	mem=nopentium	[BUGS=X86-32] Disable usage of 4MB pages for kernel

			memory.