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/sysfs-kernel-mm-ksm | 61 +++++++++++++++++++++++++++ 1 file changed, 61 insertions(+) create mode 100644 Documentation/ABI/testing/sysfs-kernel-mm-ksm (limited to 'Documentation/ABI/testing/sysfs-kernel-mm-ksm') diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-ksm b/Documentation/ABI/testing/sysfs-kernel-mm-ksm new file mode 100644 index 000000000..6041a025b --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-mm-ksm @@ -0,0 +1,61 @@ +What: /sys/kernel/mm/ksm +Date: September 2009 +KernelVersion: 2.6.32 +Contact: Linux memory management mailing list +Description: Interface for Kernel Samepage Merging (KSM) + +What: /sys/kernel/mm/ksm/full_scans +What: /sys/kernel/mm/ksm/pages_shared +What: /sys/kernel/mm/ksm/pages_sharing +What: /sys/kernel/mm/ksm/pages_to_scan +What: /sys/kernel/mm/ksm/pages_unshared +What: /sys/kernel/mm/ksm/pages_volatile +What: /sys/kernel/mm/ksm/run +What: /sys/kernel/mm/ksm/sleep_millisecs +Date: September 2009 +Contact: Linux memory management mailing list +Description: Kernel Samepage Merging daemon sysfs interface + + full_scans: how many times all mergeable areas have been + scanned. + + pages_shared: how many shared pages are being used. + + pages_sharing: how many more sites are sharing them i.e. how + much saved. + + pages_to_scan: how many present pages to scan before ksmd goes + to sleep. + + pages_unshared: how many pages unique but repeatedly checked + for merging. + + pages_volatile: how many pages changing too fast to be placed + in a tree. + + run: write 0 to disable ksm, read 0 while ksm is disabled. + + - write 1 to run ksm, read 1 while ksm is running. + - write 2 to disable ksm and unmerge all its pages. + + sleep_millisecs: how many milliseconds ksm should sleep between + scans. + + See Documentation/mm/ksm.rst for more information. + +What: /sys/kernel/mm/ksm/merge_across_nodes +Date: January 2013 +KernelVersion: 3.9 +Contact: Linux memory management mailing list +Description: Control merging pages across different NUMA nodes. + + When it is set to 0 only pages from the same node are merged, + otherwise pages from all nodes can be merged together (default). + +What: /sys/kernel/mm/ksm/general_profit +Date: April 2023 +KernelVersion: 6.4 +Contact: Linux memory management mailing list +Description: Measure how effective KSM is. + general_profit: how effective is KSM. The formula for the + calculation is in Documentation/admin-guide/mm/ksm.rst. -- cgit v1.3.1