fs/proc/base.c | 4 ++++ 1 file changed, 4 insertions(+)
From: xu xin <xu.xin16@zte.com.cn>
In /proc/<pid>/ksm_stat, Add two extra ksm involvement items including
MMF_VM_MERGEABLE and MMF_VM_MERGE_ANY. It helps administrators to
better know the system's KSM behavior at process level.
KSM_mergeable: yes/no
whether the process'mm is added by madvise() into the candidate list
of KSM or not.
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.
Changelog
=========
v1 -> v2:
replace the internal flag names with straightforward strings.
* MMF_VM_MERGEABLE -> KSM_mergeable
* MMF_VM_MERGE_ANY -> KSM_merge_any
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
---
fs/proc/base.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 18550c071d71..50e808ffcda4 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -3217,6 +3217,10 @@ static int proc_pid_ksm_stat(struct seq_file *m, struct pid_namespace *ns,
seq_printf(m, "ksm_zero_pages %lu\n", mm->ksm_zero_pages);
seq_printf(m, "ksm_merging_pages %lu\n", mm->ksm_merging_pages);
seq_printf(m, "ksm_process_profit %ld\n", ksm_process_profit(mm));
+ seq_printf(m, "KSM_mergeable: %s\n",
+ test_bit(MMF_VM_MERGEABLE, &mm->flags) ? "yes" : "no");
+ seq_printf(m, "KSM_merge_any: %s\n",
+ test_bit(MMF_VM_MERGE_ANY, &mm->flags) ? "yes" : "no");
mmput(mm);
}
--
2.15.2
On 26.04.24 03:46, xu.xin16@zte.com.cn wrote: > From: xu xin <xu.xin16@zte.com.cn> > > In /proc/<pid>/ksm_stat, Add two extra ksm involvement items including > MMF_VM_MERGEABLE and MMF_VM_MERGE_ANY. It helps administrators to > better know the system's KSM behavior at process level. > > KSM_mergeable: yes/no > whether the process'mm is added by madvise() into the candidate list > of KSM or not. > 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. > Thinking about it, we should avoid exposing internal toggles with unclear semantics to the user. See below. > Changelog > ========= > v1 -> v2: > replace the internal flag names with straightforward strings. > * MMF_VM_MERGEABLE -> KSM_mergeable > * MMF_VM_MERGE_ANY -> KSM_merge_any > > Signed-off-by: xu xin <xu.xin16@zte.com.cn> > --- > fs/proc/base.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/fs/proc/base.c b/fs/proc/base.c > index 18550c071d71..50e808ffcda4 100644 > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -3217,6 +3217,10 @@ static int proc_pid_ksm_stat(struct seq_file *m, struct pid_namespace *ns, > seq_printf(m, "ksm_zero_pages %lu\n", mm->ksm_zero_pages); > seq_printf(m, "ksm_merging_pages %lu\n", mm->ksm_merging_pages); > seq_printf(m, "ksm_process_profit %ld\n", ksm_process_profit(mm)); > + seq_printf(m, "KSM_mergeable: %s\n", > + test_bit(MMF_VM_MERGEABLE, &mm->flags) ? "yes" : "no"); All it *currently* means is "we called __ksm_enter()" once. It does not mean that KSM is still enabled for that process and that any VMA would be considered for merging. I don't think we should expose this. That information can be more reliably had by looking at "/proc/pid/smaps" and looking for "mg". Which tells you exactly if any VMA (and which) is currently applicable to KSM. > + seq_printf(m, "KSM_merge_any: %s\n", > + test_bit(MMF_VM_MERGE_ANY, &mm->flags) ? "yes" : "no"); This makes more sense to export. It's the same as reading prctl(PR_GET_MEMORY_MERGE). The man page [1] calls it simply "KSM has been enabled for this process", so process-wide KSM compared to per-VMA KSM. "KSM_enabled:" *might* be more reasonable in the context of PR_SET_MEMORY_MERGE. It wouldn't tell though if KSM is enabled on the system, though. [1] https://lore.kernel.org/linux-mm/20230227220206.436662-1-shr@devkernel.io/T/ -- Cheers, David / dhildenb
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