linux-kernel - Re: [RFC PATCH 0/3] asynchronously scan and free empty user PTE pages

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Message-ID: <a98fe84d-1fa9-47b7-824a-fc612d94d564@bytedance.com>
Date: Tue, 18 Jun 2024 15:52:45 +0800
From: Qi Zheng <zhengqi.arch@...edance.com>
To: David Hildenbrand <david@...hat.com>
Cc: Qi Zheng <zhengqi.arch@...edance.com>, hughd@...gle.com,
 willy@...radead.org, mgorman@...e.de, muchun.song@...ux.dev,
 akpm@...ux-foundation.org, linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 0/3] asynchronously scan and free empty user PTE pages



On 2024/6/18 01:51, David Hildenbrand wrote:
> On 14.06.24 05:32, Qi Zheng wrote:
>> Hi David,
>>
>> How about starting with this:
>>
>> a. for MADV_DONTNEED case, try synchronous reclaim as you said
>> b. for MADV_FREE case, add a madvise(MADV_PT_RECLAIM) option to mark
>>      this vma, then add its corresponding mm to a global list, and then
>>      traverse the list and reclaim it when the memory is tight and enters
>>      the system reclaim path.
>>
>>      (If this option is for synchronous reclaim as you said, then the
>>       user-mode program may need to start a thread to make a cyclic call.
>>       I'm not sure if this usage makes sense. If so, I can also implement
>>       such an option.)
>> c. for s390 case you mentioned, maybe we can set a CONFIG_FREE_PT first,
>>      and then s390 will not select this config until the problem is 
>> solved.
> 
> CONFIG_PT_RECLAIM or sth. like that, that would depend on 
> CONFIG_ARCH_SUPPORTS_PT_RECLAIM.
> 
> Then we can start with what we know works and was tested (e.g., x86).

OK, will do.

>