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Message-ID: <ebea3b6f-efc0-4d98-bf4d-3e2b867fa886@redhat.com>
Date:   Tue, 12 Dec 2023 14:45:26 +0100
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH v3 2/4] mm/ksm: add sysfs knobs for advisor
Content-Language: en-US
To:     Stefan Roesch <shr@devkernel.io>, kernel-team@fb.com
Cc:     akpm@linux-foundation.org, hannes@cmpxchg.org, riel@surriel.com,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
References: <20231204234906.1237478-1-shr@devkernel.io>
 <20231204234906.1237478-3-shr@devkernel.io>
From:   David Hildenbrand <david@redhat.com>
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Organization: Red Hat
In-Reply-To: <20231204234906.1237478-3-shr@devkernel.io>
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On 05.12.23 00:49, Stefan Roesch wrote:
> This adds four new knobs for the KSM advisor to influence its behaviour.
> 
> The knobs are:
> - advisor_mode:
>      none:      no advisor (default)
>      scan-time: scan time advisor
> - advisor_max_cpu: 70 (default, cpu usage percent)
> - advisor_min_pages: 500 (default)
> - advisor_max_pages: 30000 (default)
> - advisor_target_scan_time: 200 (default in seconds)
> 
> The new values will take effect on the next scan round.
> 
> Signed-off-by: Stefan Roesch <shr@devkernel.io>
> ---
>   mm/ksm.c | 127 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 127 insertions(+)
> 
> diff --git a/mm/ksm.c b/mm/ksm.c
> index b27010fa2e946..18b7185bbc65b 100644
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -3735,6 +3735,128 @@ static ssize_t smart_scan_store(struct kobject *kobj,
>   }
>   KSM_ATTR(smart_scan);
>   
> +static ssize_t advisor_mode_show(struct kobject *kobj,
> +				 struct kobj_attribute *attr, char *buf)
> +{
> +	const char *output;
> +
> +	if (ksm_advisor == KSM_ADVISOR_NONE)
> +		output = "[none] scan-time";
> +	else if (ksm_advisor == KSM_ADVISOR_SCAN_TIME)
> +		output = "none [scan-time]";
> +
> +	return sysfs_emit(buf, "%s\n", output);
> +}
> +
> +static ssize_t advisor_mode_store(struct kobject *kobj,
> +				  struct kobj_attribute *attr, const char *buf,
> +				  size_t count)
> +{
> +	if (sysfs_streq("scan-time", buf))
> +		ksm_advisor = KSM_ADVISOR_SCAN_TIME;
> +	else if (sysfs_streq("none", buf))
> +		ksm_advisor = KSM_ADVISOR_NONE;
> +	else
> +		return -EINVAL;
> +
> +	/* Set advisor default values */
> +	init_advisor();

Is the "init_advisor()" really required?

> +	set_advisor_defaults();

That function should go to this patch.


-- 
Cheers,

David / dhildenb