Re: [PATCH v9 2/3] mm: add new KSM process and sysfs knobs

[Stefan Roesch <shr@devkernel.io>]

xu xin <xu.xin.sc@gmail.com> writes:

>> This adds the general_profit KSM sysfs knob and the process profit metric
>> knobs to ksm_stat.
>>
>> 1) expose general_profit metric
>>
>>    The documentation mentions a general profit metric, however this
>>    metric is not calculated.  In addition the formula depends on the size
>>    of internal structures, which makes it more difficult for an
>>    administrator to make the calculation.  Adding the metric for a better
>>    user experience.
>>
>> 2) document general_profit sysfs knob
>>
>> 3) calculate ksm process profit metric
>>
>>    The ksm documentation mentions the process profit metric and how to
>>    calculate it.  This adds the calculation of the metric.
>>
>> 4) mm: expose ksm process profit metric in ksm_stat
>>
>>    This exposes the ksm process profit metric in /proc/<pid>/ksm_stat.
>>    The documentation mentions the formula for the ksm process profit
>>    metric, however it does not calculate it.  In addition the formula
>>    depends on the size of internal structures.  So it makes sense to
>>    expose it.
>>
>
> Hi, Stefan, I think you should give some credits to me about my contributions on
> the concept and formula of ksm profit (process wide and system wide),  it's kind
> of idea stealing.
>
>

I wasn't aware the formula that is described in the documentation is
from you. I simply implemented the documented metrics. If you came up
with it, happy to give you credit.

> Besides, the idea of Process control KSM was proposed by me last year although you use
> prctl instead of /proc fs. you even didn't CC my email. I think you should CC my email
> (xu.xin16@zte.com.cn) as least.
>
>> 5) document new procfs ksm knobs
>>
>> Signed-off-by: Stefan Roesch <shr@devkernel.io>
>> Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
>> Acked-by: David Hildenbrand <david@redhat.com>
>> Cc: David Hildenbrand <david@redhat.com>
>> Cc: Johannes Weiner <hannes@cmpxchg.org>
>> Cc: Michal Hocko <mhocko@suse.com>
>> Cc: Rik van Riel <riel@surriel.com>
>> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
>> ---
>>  Documentation/ABI/testing/sysfs-kernel-mm-ksm |  8 +++++++
>>  Documentation/admin-guide/mm/ksm.rst          |  5 ++++-
>>  fs/proc/base.c                                |  3 +++
>>  include/linux/ksm.h                           |  4 ++++
>>  mm/ksm.c                                      | 21 +++++++++++++++++++
>>  5 files changed, 40 insertions(+), 1 deletion(-)
>>
>> diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-ksm b/Documentation/ABI/testing/sysfs-kernel-mm-ksm
>> index d244674a9480..6041a025b65a 100644
>> --- a/Documentation/ABI/testing/sysfs-kernel-mm-ksm
>> +++ b/Documentation/ABI/testing/sysfs-kernel-mm-ksm
>> @@ -51,3 +51,11 @@ 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 <linux-mm@kvack.org>
>> +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.
>> diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst