From 3ab76c767bc783c122a8dfe105fbc10a0b029b42 Mon Sep 17 00:00:00 2001 From: xu xin Date: Fri, 10 Jan 2025 17:40:34 +0800 Subject: ksm: add ksm involvement information for each process In /proc//ksm_stat, add two extra ksm involvement items including KSM_mergeable and KSM_merge_any. It helps administrators to better know the system's KSM behavior at process level. ksm_merge_any: yes/no whether the process'mm is added by prctl() into the candidate list of KSM or not, and fully enabled at process level. ksm_mergeable: yes/no whether any VMAs of the process'mm are currently applicable to KSM. Purpose ======= These two items are just to improve the observability of KSM at process level, so that users can know if a certain process has enabled KSM. For example, if without these two items, when we look at /proc//ksm_stat and there's no merging pages found, We are not sure whether it is because KSM was not enabled or because KSM did not successfully merge any pages. Although "mg" in /proc//smaps indicate VM_MERGEABLE, it's opaque and not very obvious for non professionals. [akpm@linux-foundation.org: wording tweaks, per David and akpm] Link: https://lkml.kernel.org/r/20250110174034304QOb8eDoqtFkp3_t8mqnqc@zte.com.cn Signed-off-by: xu xin Acked-by: David Hildenbrand Tested-by: Mario Casquero Cc: Wang Yaxin Cc: Yang Yang Signed-off-by: Andrew Morton --- include/linux/ksm.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/ksm.h') diff --git a/include/linux/ksm.h b/include/linux/ksm.h index 6a53ac4885bb..d73095b5cd96 100644 --- a/include/linux/ksm.h +++ b/include/linux/ksm.h @@ -93,6 +93,7 @@ void folio_migrate_ksm(struct folio *newfolio, struct folio *folio); void collect_procs_ksm(const struct folio *folio, const struct page *page, struct list_head *to_kill, int force_early); long ksm_process_profit(struct mm_struct *); +bool ksm_process_mergeable(struct mm_struct *mm); #else /* !CONFIG_KSM */ -- cgit v1.2.3