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Thu, 2 Apr 2026 10:07:39 +0800 (CST) Received: from dggpemf200002.china.huawei.com (unknown [7.185.36.244]) by mail.maildlp.com (Postfix) with ESMTPS id 08EEB203B2; Thu, 2 Apr 2026 10:13:29 +0800 (CST) Received: from [10.174.178.174] (10.174.178.174) by dggpemf200002.china.huawei.com (7.185.36.244) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Thu, 2 Apr 2026 10:13:27 +0800 Subject: Re: [PATCH -next] mm: vmstat: make refresh interval take effect immediately To: "David Hildenbrand (Arm)" , , , , , , , , , CC: , , Yangyingliang References: <20260326075546.3357901-1-yangyingliang@huawei.com> From: Yang Yingliang Message-ID: Date: Thu, 2 Apr 2026 10:13:26 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/alternative; boundary="------------AEE0935252EE36F7617A5695" Content-Language: en-US X-Originating-IP: [10.174.178.174] X-ClientProxiedBy: kwepems500001.china.huawei.com (7.221.188.70) To dggpemf200002.china.huawei.com (7.185.36.244) X-Stat-Signature: 4pe14bakh5hnrr6bmnjcyfyty576qcy3 X-Rspamd-Queue-Id: 4F2FB140007 X-Rspam-User: X-Rspamd-Server: rspam03 X-HE-Tag: 1775096013-584804 X-HE-Meta: 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 /l1z11lK 4ZjFOil0H99vNAvzyootai+xsIaOZlcg//VWOTXsDPp9ZTP8E0AoJ8sbbVyhYfIg8uzo53N7A3oNrqTLkGtTkUm9aVSw13HrkiKyQhtXbXD0DrR/EKbuMGpDm8lsS+T2MobBzRz3GqM2nDqIrQON3XmEAvTJF6g2ljchoFBk8Gvp8jv7SKcfMhv5DwYUihJsVDipvw8YvOHcuP9veT6lxkFxTIwCLiO3kwFJwrdrjXPH96vO3FW21w2OUxMJ0w5Bfer7NyoNo+yfPorKIzAQwih1SBfLc+Z8TkDG92y0FUTbv6gHM4BCdOBSEmOuLW5cj/DQxxhOJGx8QBmkbUlnE7V4kWr3BTbPrWYr8b0DEaXvjAsf4iOyIbLQCmdFrojBqrVaUNeUMAkfxI86xK2GkPnsQ/Q== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: --------------AEE0935252EE36F7617A5695 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit On 2026/3/26 18:09, David Hildenbrand (Arm) wrote: > On 3/26/26 08:55, Yang Yingliang wrote: >> The refresh workqueue is re-queued after last timer is triggered, so when >> the refresh interval is set, it doesn't take effect immediately. >> >> It leads a problem like this: if current interval is 8640000s (100 days), >> and we want changing it to 1s, the new interval can't take effect until >> 100 days later. > Well, yes. But, the default is set to HZ. If you set the default to > 100days you are probably doing something very wrong in the first place? It's a fuzzy test. > > What's the use case that warrants the complexity? Even when set to, say, > 30s, waiting 30s is not that bad. > > Would we maybe just want to set an upper limit to which we clamp? That > would be a lot simpler. Is this too strict ? If someone want to set 1min or more, but it's limited. Some existing scripts function may be broken. > --------------AEE0935252EE36F7617A5695 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: 7bit


On 2026/3/26 18:09, David Hildenbrand (Arm) wrote:
On 3/26/26 08:55, Yang Yingliang wrote:

The refresh workqueue is re-queued after last timer is triggered, so when
the refresh interval is set, it doesn't take effect immediately.

It leads a problem like this: if current interval is 8640000s (100 days),
and we want changing it to 1s, the new interval can't take effect until
100 days later.

Well, yes. But, the default is set to HZ. If you set the default to
100days you are probably doing something very wrong in the first place?
It's a fuzzy test.

What's the use case that warrants the complexity? Even when set to, say,
30s, waiting 30s is not that bad.

Would we maybe just want to set an upper limit to which we clamp? That
would be a lot simpler.

Is this too strict ? If someone want to set 1min or more, but it's limited. Some existing

scripts function may be broken.
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