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Wed, 20 Aug 2025 05:16:59 -0700 (PDT) Message-ID: <24119aa3-f6ef-4467-80a0-475989e19625@gmail.com> Date: Wed, 20 Aug 2025 16:16:56 +0400 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/3] memcg, writeback: Don't wait writeback completion To: Julian Sun , linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, linux-mm@kvack.org Cc: 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, tj@kernel.org References: <20250820111940.4105766-1-sunjunchao@bytedance.com> Content-Language: en-US From: Giorgi Tchankvetadze In-Reply-To: <20250820111940.4105766-1-sunjunchao@bytedance.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Could we add wb_pending_pages to memory.events? Very cheap and useful. A single atomic counter is already kept internally; exposing it is one line in memcontrol.c plus one line in the ABI doc. On 8/20/2025 3:19 PM, Julian Sun wrote: > This patch series aims to eliminate task hangs in mem_cgroup_css_free() > caused by calling wb_wait_for_completion(). > This is because there may be a large number of writeback tasks in the > foreign memcg, involving millions of pages, and the situation is > exacerbated by WBT rate limiting—potentially leading to task hangs > lasting several hours. > > Patch 1 is preparatory work and involves no functional changes. > Patch 2 implements the automatic release of wb_completion. > Patch 3 removes wb_wait_for_completion() from mem_cgroup_css_free(). > > > Julian Sun (3): > writeback: Rename wb_writeback_work->auto_free to free_work. > writeback: Add wb_writeback_work->free_done > memcg: Don't wait writeback completion when release memcg. > > fs/fs-writeback.c | 22 ++++++++++++++-------- > include/linux/backing-dev-defs.h | 6 ++++++ > include/linux/memcontrol.h | 2 +- > mm/memcontrol.c | 29 ++++++++++++++++++++--------- > 4 files changed, 41 insertions(+), 18 deletions(-) >