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b=fKKP0aaflcesVE16gmCdIUQZXRadXKPNnorPID/XlTMeQNeLHsIR28CRvP+c6tv0J GiCgXFFIpH2jQffDALJEoRKtEpNvFEK/wsgTFqXso/t6JYdOaw2xjsePWdkwspBvrk LAcdnbsVjFw2Rq9h4BiQ69Sk4X/EaJA7hQhJhbvTOuMR9DA8JqwLBB99tjjrjz34o6 D8XYz0iZ4U515IRFaGmbyVSZ6WyRGrmMhaMfYv25FKZTceSb2wGwabvOSN6HmubtGj ND6iPTXtl32xcMeLHue7tZns05qcKFHWgznrw+8cFKUft+K5WGYP2xuRtxkRyswykU 0DapLWAEcv6qQ== Date: Thu, 13 Aug 2026 10:27:09 +0100 From: "Lorenzo Stoakes (ARM)" To: Shakeel Butt Cc: Andrew Morton , Michal Hocko , Johannes Weiner , Roman Gushchin , Muchun Song , David Hildenbrand , Kairui Song , Qi Zheng , Barry Song , Axel Rasmussen , Meta kernel team , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH for-7.4 0/9] memcg: remove the v1 soft limit Message-ID: References: <20260811203203.3456029-1-shakeel.butt@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260811203203.3456029-1-shakeel.butt@linux.dev> X-Stat-Signature: h4erzbz9u6fnc1zied1ik47wbd91qfog X-Rspamd-Queue-Id: F40801A000A X-Rspamd-Server: rspam03 X-Rspam-User: X-HE-Tag: 1786613250-892680 X-HE-Meta: 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 LvYwZqwj 03KZx7H54m4iNL4PNENKIlSGIgJUcUkcEZXKYP2uOQOrivC8e/em5+Bz8MaI8RiRVERhQptoyUpx5n57mvngJ5WQz26swENsZ2DZeyn8fmBvKwG2zl0LgwhsPWunNZE/D7hTBIrFtfKzcQoXWP79SBhCpQxfrR8YYRycQ8k0qj1FEmDe0jOBavuTVop9/DdhnCjcY/Aw+Jv76f206RHFfEoyIBDbkyBFTDU4Gu0PX9ohJvb5LP7JGyDkuLKaHLpjoHrVtZRf2Af+5OzubhFhGfEAh3dmWL8Xj2xzs9OVxlHfwe+c= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Aug 11, 2026 at 01:31:54PM -0700, Shakeel Butt wrote: > Syzbot reported [1] a set_mm_walk() warning from kswapd. Soft limit > reclaim is the only thing that runs shrink_lruvec() from kswapd with a > target memcg set, and thus the only way kswapd can reach > lru_gen_shrink_lruvec() and in turn set_mm_walk(). The offender, > mem_cgroup_shrink_node(), has long carried a "Only used by soft limit > reclaim. Do not reuse for anything else." comment and a priority hack, > and it simply never got taught about MGLRU. > > Rather than teach it, let's delete it. The v1 soft limit was deprecated > in v6.12 by commit 569c4f62d84a ("memcg: initiate deprecation of v1 > soft limit"). Nobody has reported depending on it in the ~21 months > since, and v2 has covered the same ground for a long time with > memory.low and memory.min. > > Link: https://lore.kernel.org/all/6a7a6929.b50370da.49fe0.005e.GAE@google.com/ [1] > > Shakeel Butt (9): > memcg: make the v1 soft limit knob inert > memcg: remove v1 soft limit reclaim > memcg: remove mem_cgroup_shrink_node() > memcg: remove the soft limit reclaim tracepoints > memcg: remove the soft limit rbtree > memcg: remove lru_gen_soft_reclaim() > memcg: remove the per-node soft limit tree fields > memcg: remove mem_cgroup->soft_limit > memcg: simplify v1 event ratelimiting > > .../admin-guide/cgroup-v1/memory.rst | 49 +- > include/linux/memcontrol.h | 27 -- > include/linux/mmzone.h | 30 +- > include/trace/events/vmscan.h | 14 - > mm/internal.h | 4 - > mm/memcontrol-v1.c | 435 ++---------------- > mm/memcontrol-v1.h | 12 +- > mm/memcontrol.c | 7 +- > mm/vmscan.c | 96 +--- > 9 files changed, 66 insertions(+), 608 deletions(-) This is a gorgeous diffstat :) Obviously not my area but looking over it, all LGTM so feel free to add: Acked-by: Lorenzo Stoakes (ARM) To the whole series! > > -- > 2.53.0-Meta > -- Cheers, Lorenzo