From: Johannes Weiner <hannes@cmpxchg.org>
To: Hao Jia <jiahao.kernel@gmail.com>
Cc: akpm@linux-foundation.org, tj@kernel.org, shakeel.butt@linux.dev,
mhocko@kernel.org, yosry@kernel.org, mkoutny@suse.com,
nphamcs@gmail.com, chengming.zhou@linux.dev,
muchun.song@linux.dev, roman.gushchin@linux.dev,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
linux-doc@vger.kernel.org, Hao Jia <jiahao1@lixiang.com>
Subject: Re: [PATCH v2 2/2] mm/zswap: Support batch writeback in shrink_memcg()
Date: Wed, 22 Jul 2026 22:27:08 -0400 [thread overview]
Message-ID: <amF7_GB5Rl6OJmt4@cmpxchg.org> (raw)
In-Reply-To: <20260717085151.22822-3-jiahao.kernel@gmail.com>
On Fri, Jul 17, 2026 at 04:51:51PM +0800, Hao Jia wrote:
> @@ -1369,7 +1402,7 @@ static void shrink_worker(struct work_struct *w)
> goto resched;
> }
>
> - ret = shrink_memcg(memcg);
> + ret = shrink_memcg(memcg, NR_ZSWAP_WB_BATCH);
> /* drop the extra reference */
> mem_cgroup_put(memcg);
>
> @@ -1493,7 +1526,7 @@ bool zswap_store(struct folio *folio)
> objcg = get_obj_cgroup_from_folio(folio);
> if (objcg && !obj_cgroup_may_zswap(objcg)) {
> memcg = get_mem_cgroup_from_objcg(objcg);
> - if (shrink_memcg(memcg)) {
> + if (shrink_memcg(memcg, 1)) {
Why 64 for the global limit but only 1 for the cgroup limit? That
seems arbitrary in multiple ways.
Direct reclaim, kswapd, proactive reclaim, cgroup limit reclaim use
SWAP_CLUSTER_MAX for the batch size near-universally. It's magic too
to be sure, but at least you wouldn't have to make up new magic?
Otherwise, the patch looks good to me.
next prev parent reply other threads:[~2026-07-23 2:27 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-17 8:51 [PATCH v2 0/2] mm/zswap: Fixes and improves the zswap global shrinker Hao Jia
2026-07-17 8:51 ` [PATCH v2 1/2] mm/zswap: Fix global shrinker when memory cgroup is disabled Hao Jia
2026-07-23 2:13 ` Johannes Weiner
2026-07-17 8:51 ` [PATCH v2 2/2] mm/zswap: Support batch writeback in shrink_memcg() Hao Jia
2026-07-17 16:45 ` Yosry Ahmed
2026-07-17 16:46 ` Nhat Pham
2026-07-23 2:27 ` Johannes Weiner [this message]
2026-07-18 1:18 ` [PATCH v2 0/2] mm/zswap: Fixes and improves the zswap global shrinker Andrew Morton
2026-07-18 1:22 ` Yosry Ahmed
2026-07-18 1:28 ` Yosry Ahmed
2026-07-18 4:40 ` Andrew Morton
2026-07-20 1:26 ` Hao Jia
2026-07-23 1:21 ` Hao Jia
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