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Add documentation for the powerpc memtrace debugfs files 

CONFIG_PPC_MEMTRACE must be set to use this feature. This can only be
used on powernv platforms.

Signed-off-by: Rashmica Gupta <rashmica.g@gmail.com>
[mpe: Update dates and kernel versions, mention size is in bytes]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
hifive-unleashed-5.1
Rashmica Gupta 2017-06-01 15:34:40 +10:00 committed by Michael Ellerman
parent 9d5171a8f2
commit 1f84c2624a
1 changed files with 45 additions and 0 deletions
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Documentation/ABI/testing/ppc-memtrace 100644
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What: /sys/kernel/debug/powerpc/memtrace
Date: Aug 2017
KernelVersion: 4.14
Contact: linuxppc-dev@lists.ozlabs.org
Description: This folder contains the relevant debugfs files for the
hardware trace macro to use. CONFIG_PPC64_HARDWARE_TRACING
must be set.
What: /sys/kernel/debug/powerpc/memtrace/enable
Date: Aug 2017
KernelVersion: 4.14
Contact: linuxppc-dev@lists.ozlabs.org
Description: Write an integer containing the size in bytes of the memory
you want removed from each NUMA node to this file - it must be
aligned to the memblock size. This amount of RAM will be removed
from the kernel mappings and the following debugfs files will be
created. This can only be successfully done once per boot. Once
memory is successfully removed from each node, the following
files are created.
What: /sys/kernel/debug/powerpc/memtrace/<node-id>
Date: Aug 2017
KernelVersion: 4.14
Contact: linuxppc-dev@lists.ozlabs.org
Description: This directory contains information about the removed memory
from the specific NUMA node.
What: /sys/kernel/debug/powerpc/memtrace/<node-id>/size
Date: Aug 2017
KernelVersion: 4.14
Contact: linuxppc-dev@lists.ozlabs.org
Description: This contains the size of the memory removed from the node.
What: /sys/kernel/debug/powerpc/memtrace/<node-id>/start
Date: Aug 2017
KernelVersion: 4.14
Contact: linuxppc-dev@lists.ozlabs.org
Description: This contains the start address of the removed memory.
What: /sys/kernel/debug/powerpc/memtrace/<node-id>/trace
Date: Aug 2017
KernelVersion: 4.14
Contact: linuxppc-dev@lists.ozlabs.org
Description: This is where the hardware trace macro will output the trace
it generates.