Re: [PATCH v11 09/15] khugepaged: add per-order mTHP collapse failure statistics
From: Baolin Wang <baolin.wang@linux.alibaba.com>
Date: 2025-09-12 09:40:57
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On 2025/9/12 11:28, Nico Pache wrote:
Add three new mTHP statistics to track collapse failures for different orders when encountering swap PTEs, excessive none PTEs, and shared PTEs: - collapse_exceed_swap_pte: Increment when mTHP collapse fails due to swap PTEs - collapse_exceed_none_pte: Counts when mTHP collapse fails due to exceeding the none PTE threshold for the given order - collapse_exceed_shared_pte: Counts when mTHP collapse fails due to shared PTEs These statistics complement the existing THP_SCAN_EXCEED_* events by providing per-order granularity for mTHP collapse attempts. The stats are exposed via sysfs under `/sys/kernel/mm/transparent_hugepage/hugepages-*/stats/` for each supported hugepage size. As we currently dont support collapsing mTHPs that contain a swap or shared entry, those statistics keep track of how often we are encountering failed mTHP collapses due to these restrictions. Signed-off-by: Nico Pache <npache@redhat.com> ---
LGTM. Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>