From: Yosry Ahmed <yosry@kernel.org>
To: Nhat Pham <nphamcs@gmail.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>,
Minchan Kim <minchan@kernel.org>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Yosry Ahmed <yosry.ahmed@linux.dev>,
Nhat Pham <hoangnhat.pham@linux.dev>,
Chengming Zhou <chengming.zhou@linux.dev>,
Michal Hocko <mhocko@kernel.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Shakeel Butt <shakeel.butt@linux.dev>,
Muchun Song <muchun.song@linux.dev>,
Andrew Morton <akpm@linux-foundation.org>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, kernel-team@meta.com
Subject: Re: [PATCH 6/8] mm/zsmalloc, zswap: Handle objcg charging and lifetime in zsmalloc
Date: Wed, 4 Mar 2026 08:45:47 -0800 [thread overview]
Message-ID: <CAO9r8zMbU8ikA4jAUyOvvorsm3L4UD2X-KVcGyQaKwTZ0nV1Qw@mail.gmail.com> (raw)
In-Reply-To: <CAKEwX=ObFWm6cKbi4hL8JLDKui3MsRu-JpEFohBdkqHFY9tVfA@mail.gmail.com>
> > AFAICT the only zswap-specific part is the actual stat indexes, what
> > if these are parameterized at the zsmalloc pool level? AFAICT zswap
> > and zram will never share a pool.
>
> TBH, if we were to start from scratch, these should be zsmalloc
> counters not zswap counters. Only zsmalloc knows about the memory
> placement and real memory consumption (i.e taking into account
> intra-slot wasted space) - this information is abstracted away from
> all of the callers.
I agree, but we cannot change the zswap stats now that we added them.
Keep in mind that when they were added zsmalloc was not the only
backend.
> And if/when zram supports cgroup tracking, memory
> used by zswap and memory used by zram is indistinguishable, no?
It is distinguishable as long as they use different zsmalloc pools, I
don't see why we'd need to share a pool.
> Anyway, Joshua, do you think this is doable? Seems promising to me,
> but idk if it will be clean to implement or not.
Not sure what you mean here? Changing the stats to be zsmalloc-based?
IIUC we can't do this without breaking userspace.
next prev parent reply other threads:[~2026-03-04 16:46 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-02-26 19:29 [PATCH 0/8] mm/zswap, zsmalloc: Per-memcg-lruvec zswap accounting Joshua Hahn
2026-02-26 19:29 ` [PATCH 1/8] mm/zsmalloc: Rename zs_object_copy to zs_obj_copy Joshua Hahn
2026-02-26 19:29 ` [PATCH 2/8] mm/zsmalloc: Make all obj_idx unsigned ints Joshua Hahn
2026-02-26 19:29 ` [PATCH 3/8] mm/zsmalloc: Introduce objcgs pointer in struct zpdesc Joshua Hahn
2026-02-26 21:37 ` Shakeel Butt
2026-02-26 21:43 ` Joshua Hahn
2026-03-04 16:58 ` Yosry Ahmed
2026-03-04 18:03 ` Joshua Hahn
2026-02-26 19:29 ` [PATCH 4/8] mm/zsmalloc: Store obj_cgroup pointer in zpdesc Joshua Hahn
2026-02-26 19:29 ` [PATCH 5/8] mm/zsmalloc,zswap: Redirect zswap_entry->obcg to zpdesc Joshua Hahn
2026-02-26 23:13 ` kernel test robot
2026-02-27 19:10 ` Joshua Hahn
2026-02-26 19:29 ` [PATCH 6/8] mm/zsmalloc, zswap: Handle objcg charging and lifetime in zsmalloc Joshua Hahn
2026-03-03 23:53 ` Yosry Ahmed
2026-03-04 15:11 ` Joshua Hahn
2026-03-04 15:46 ` Yosry Ahmed
2026-03-04 16:26 ` Joshua Hahn
2026-03-04 16:27 ` Nhat Pham
2026-03-04 16:45 ` Yosry Ahmed [this message]
2026-03-04 16:49 ` Nhat Pham
2026-02-26 19:29 ` [PATCH 7/8] mm/memcontrol: Track MEMCG_ZSWAPPED in bytes Joshua Hahn
2026-02-26 19:29 ` [PATCH 8/8] mm/vmstat, memcontrol: Track ZSWAP_B, ZSWAPPED_B per-memcg-lruvec Joshua Hahn
2026-02-26 22:40 ` kernel test robot
2026-02-27 19:45 ` Joshua Hahn
2026-02-26 23:02 ` kernel test robot
2026-03-02 21:31 ` [PATCH 0/8] mm/zswap, zsmalloc: Per-memcg-lruvec zswap accounting Nhat Pham
2026-03-03 17:51 ` Joshua Hahn
2026-03-03 18:01 ` Nhat Pham
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