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

[Hao Jia]

On 2026/5/26 03:24, Andrew Morton wrote:
> On Mon, 25 May 2026 20:22:38 +0800 Hao Jia <jiahao.kernel@xxxxxxxxx> 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@xxxxxxxxx

Thanks,
Hao