title: Log the kernel collapsing normal pages into a huge page
name: hugepage_collapse.stp
version: 1.0
author: William Cohen
keywords: memory
subsystem: memory
status: production
exit: user-controlled
output: sorted-list
scope: system-wide
description: The kernel may attempt to group many normal sized pages into a single huge page to improve TLB performance.  This operation may take a significant amount of time and affect program performance.  You can identify if huge page collapse operations are occurring with the systemtap hugepage_collapse.stp script.
test_support: stap -l 'kernel.function("collapse_huge_page")'
test_check: stap -p4 hugepage_collapse.stp
test_installcheck: stap hugepage_collapse.stp -T 1