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To: Tejun Heo Cc: linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, muchun.song@linux.dev, axboe@kernel.dk Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: B490780008 X-Stat-Signature: z9g1z1ffcwpo1aikhka1ed3ccbkki4ba X-Rspam-User: X-HE-Tag: 1755743443-953804 X-HE-Meta: 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 7jIyugEW /PKU3sDjySmBBoDI6z2AOqYdjEiy3qXigKdMzlp04zcVGkv2hbo3ZN/XGxiSJyp0iEX6NWUhN2Z/uk+58yql3YMIL/H9rXd8ENc7ni9GcZuzuTQuV8n0Gr40jcfCoRod76f6EuuQq75kSXB3znptIJpyqqPiAzeDEhDlBHEvS+RB/5QEMOsW/024CY+5lIrS6XnUEfdg6K7/m/NWUV5BWUXfJLFE2oo08NPWcoA0fv+1GZZ4= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Aug 21, 2025 at 4:58=E2=80=AFAM Tejun Heo wrote: > > On Wed, Aug 20, 2025 at 07:19:40PM +0800, Julian Sun wrote: > > @@ -3912,8 +3921,12 @@ static void mem_cgroup_css_free(struct cgroup_su= bsys_state *css) > > int __maybe_unused i; > > > > #ifdef CONFIG_CGROUP_WRITEBACK > > - for (i =3D 0; i < MEMCG_CGWB_FRN_CNT; i++) > > - wb_wait_for_completion(&memcg->cgwb_frn[i].done); > > + for (i =3D 0; i < MEMCG_CGWB_FRN_CNT; i++) { > > + struct wb_completion *done =3D memcg->cgwb_frn[i].done; > > + > > + if (atomic_dec_and_test(&done->cnt)) > > + kfree(done); > > + } > > #endif > > Can't you just remove done? I don't think it's doing anything after your > changes anyway. Thanks for your review. AFAICT done is also used to track free slots in mem_cgroup_track_foreign_dirty_slowpath() and mem_cgroup_flush_foreign(), otherwise we have no method to know which one is free and might flush more than what MEMCG_CGWB_FRN_CNT allow. Am I missing something? Thanks, > > Thanks. > > -- > tejun