Re: [PATCH v2 0/4] mm/zswap: Implement per-cgroup proactive writeback

[Hao Jia <jiahao.kernel@gmail.com>]

On 2026/5/27 02:55, Yosry Ahmed wrote:
> On Tue, May 26, 2026 at 4:56 AM Hao Jia <jiahao.kernel@gmail.com> wrote:
>>
>>
>>
>> On 2026/5/26 03:24, Andrew Morton wrote:
>>> On Mon, 25 May 2026 20:22:38 +0800 Hao Jia <jiahao.kernel@gmail.com> wrote:
>>>
>>>> Zswap currently writes back pages to backing swap reactively, triggered
>>>> either by the shrinker or by the pool reaching its size limit. Although
>>>> proactive memory reclaim can automatically write back a portion of zswap
>>>> pages via the shrinker, it cannot explicitly control the amount of
>>>> writeback for a specific memory cgroup. Moreover, proactive memory reclaim
>>>> may not always be triggered during a steady state.
>>>>
>>>> In certain scenarios, it is desirable to trigger writeback in advance to
>>>> free up memory. For example, users may want to prepare for an upcoming
>>>> memory-intensive workload by flushing cold memory to the backing storage
>>>> when the system is relatively idle.
>>>>
>>>> This patch series introduces a "zswap_writeback_only" key to memory.reclaim
>>>> cgroup interface, allowing users to proactively write back cold compressed
>>>> pages from zswap to the backing swap device. When specified, this key
>>>> bypasses standard memory reclaim and exclusively performs proactive zswap
>>>> writeback up to the requested budget. If omitted, the default reclaim
>>>> behavior remains unchanged.
>>>
>>> Thanks.  AI review found a few things to complain about, one of them
>>> described as "preexisting".
>>>
>>
>> Thanks Andrew.  I have replied to the AI's review comments in a separate
>> email and posted v3.
>> https://lore.kernel.org/all/20260526114601.67041-1-jiahao.kernel@gmail.com
> 
> Generally speaking, please give time for reviewers to take a look
> before sending a new version. Less than a day is usually too fast
> (unless you're iterating super fast with the reviewers). Review
> feedback does not have to be addressed immediately, usually wait for a
> bit to collect as much feedback as possible before spinning a new
> version.
>

Thanks for the advice, Yosry. Got it.

> I will take a look at v3 soon, thank you.

Appreciate you taking a look at v3.

Thakns,
Hao