From 119e9db233ad0f4cbd4cfb9f9385a7bca378b37d Mon Sep 17 00:00:00 2001 From: Zeng Chi Date: Mon, 21 Sep 2026 18:24:42 +0800 Subject: KVM: Don't pre-reserve xarray entries when storing empty/NULL attributes Skip the xarray reservation loop when clearing all memory attributes, as storing NULL only erases the entry and never needs to allocate, so no reservation (and no cleanup of a failed one) is required in that case. Suggested-by: Sean Christopherson Cc: David Ballesteros Signed-off-by: Zeng Chi Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com [sean: split to separate patch] Signed-off-by: Sean Christopherson --- Documentation/ABI/testing/ppc-memtrace | 46 ++++++++++++++++++++++++++++++++++ 1 file changed, 46 insertions(+) create mode 100644 Documentation/ABI/testing/ppc-memtrace (limited to 'Documentation/ABI/testing/ppc-memtrace') diff --git a/Documentation/ABI/testing/ppc-memtrace b/Documentation/ABI/testing/ppc-memtrace new file mode 100644 index 000000000..9606aed33 --- /dev/null +++ b/Documentation/ABI/testing/ppc-memtrace @@ -0,0 +1,46 @@ +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 each NUMA node in the kernel mappings and the following + debugfs files will be created. Once memory is successfully + removed from each node, the following files are created. To + re-add memory to the kernel, echo 0 into this file (it will be + automatically onlined). + +What: /sys/kernel/debug/powerpc/memtrace/ +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//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//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//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. -- cgit v1.3.1