| Message ID | 20220309122446.1118738-1-rppt@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | docs/kernel-parameters: update description of mem= | expand |
Hi Mike, On 3/9/22 04:24, Mike Rapoport wrote: > From: Mike Rapoport <rppt@linux.ibm.com> > > 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: Mike Rapoport <rppt@linux.ibm.com> > --- > > This is in a way a followup for the discussion of mem= usage on MIPS: > > https://lore.kernel.org/all/1646461289-31992-1-git-send-email-yangtiezhu@loongson.cn > > .../admin-guide/kernel-parameters.txt | 20 +++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index f5a27f067db9..f3597841a031 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -2834,6 +2834,15 @@ > 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. > + > + [HEXAGON] - must be use to set the memory size, there is Above line seems to be missing something? Otherwise looks good AFAIK. > > [X86] Work as limiting max address. Use together > with memmap= to avoid physical address space collisions. > @@ -2844,6 +2853,17 @@ > 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=nn[KMG] [HEXAGON] Set the memory size. > + Must be specified, otherwise memory size will be 0. > + > mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel > memory. >
On 3/9/22 3:24 PM, Mike Rapoport wrote: > From: Mike Rapoport <rppt@linux.ibm.com> > > 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: Mike Rapoport <rppt@linux.ibm.com> > --- > > This is in a way a followup for the discussion of mem= usage on MIPS: > > https://lore.kernel.org/all/1646461289-31992-1-git-send-email-yangtiezhu@loongson.cn > > .../admin-guide/kernel-parameters.txt | 20 +++++++++++++++++++ > 1 file changed, 20 insertions(+) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index f5a27f067db9..f3597841a031 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -2834,6 +2834,15 @@ > 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. > + > + [HEXAGON] - must be use Used? > to set the memory size, there is What? :-) [...] MBR, Sergey
On Wed, Mar 09, 2022 at 08:05:05AM -0800, Randy Dunlap wrote: > Hi Mike, > > On 3/9/22 04:24, Mike Rapoport wrote: > > From: Mike Rapoport <rppt@linux.ibm.com> > > > > 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: Mike Rapoport <rppt@linux.ibm.com> > > --- > > > > This is in a way a followup for the discussion of mem= usage on MIPS: > > > > https://lore.kernel.org/all/1646461289-31992-1-git-send-email-yangtiezhu@loongson.cn > > > > .../admin-guide/kernel-parameters.txt | 20 +++++++++++++++++++ > > 1 file changed, 20 insertions(+) > > > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > > index f5a27f067db9..f3597841a031 100644 > > --- a/Documentation/admin-guide/kernel-parameters.txt > > +++ b/Documentation/admin-guide/kernel-parameters.txt > > @@ -2834,6 +2834,15 @@ > > 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. > > + > > + [HEXAGON] - must be use to set the memory size, there is > > Above line seems to be missing something? Yes :) > Otherwise looks good AFAIK. > > > > > [X86] Work as limiting max address. Use together > > with memmap= to avoid physical address space collisions. > > @@ -2844,6 +2853,17 @@ > > 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=nn[KMG] [HEXAGON] Set the memory size. > > + Must be specified, otherwise memory size will be 0. > > + > > mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel > > memory. > > > > -- > ~Randy
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index f5a27f067db9..f3597841a031 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2834,6 +2834,15 @@ 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. + + [HEXAGON] - must be use to set the memory size, there is [X86] Work as limiting max address. Use together with memmap= to avoid physical address space collisions. @@ -2844,6 +2853,17 @@ 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=nn[KMG] [HEXAGON] Set the memory size. + Must be specified, otherwise memory size will be 0. + mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel memory.