linux-kernel - Re: [PATCH v9 2/5] ksm: count all zero pages placed by KSM

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Message-ID: <fdd99465-c4e3-7294-075f-46a9f1c3e63d@redhat.com>
Date:   Wed, 24 May 2023 10:27:47 +0200
From:   David Hildenbrand <david@...hat.com>
To:     xu xin <xu.xin.sc@...il.com>
Cc:     akpm@...ux-foundation.org, imbrenda@...ux.ibm.com,
        jiang.xuexin@....com.cn, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, ran.xiaokai@....com.cn, xu.xin16@....com.cn,
        yang.yang29@....com.cn
Subject: Re: [PATCH v9 2/5] ksm: count all zero pages placed by KSM

On 24.05.23 09:55, xu xin wrote:
>>> +extern unsigned long ksm_zero_pages;
>>> +
>>> +static inline void ksm_notify_unmap_zero_page(pte_t pte)
>>> +{
>>> +	if (is_ksm_zero_pte(pte))
>>> +		ksm_zero_pages--;
>>> +}
>>> +
>>>    static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm)
>>>    {
>>>    	int ret;
>>> @@ -103,6 +111,10 @@ static inline void ksm_exit(struct mm_struct *mm)
>>>    
>>>    #define is_ksm_zero_pte(pte)	0
>>>    
>>> +static inline void ksm_notify_unmap_zero_page(pte_t pte)
>>> +{
>>> +}
>>> +
>>
>> Having proposed that name ... I realize that we call this function
>> whenever there might be a zeropage mapped (when we have !page after
>> vm_normal_page()) -- but it could also not be the zeropage.
>>
>> Not really able to come up with a better name :)
>>
>> ksm_notify_maybe_unmap_zero_page ?
>>
>> ksm_maybe_unmap_zero_page ?
>>
> 
> Analogous to the existing name of ksm_might_need_to_copy, so maybe we can use
> 'ksm_might_unmap_zero_page',

Yes, that should work :)

-- 
Thanks,

David / dhildenb