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AJvYcCVeNj8p2TJa6agrMulv+w9Hk+EMqBoJugcFcAVCmBoXZRFqNwLkJCRBQLLGvQCKf8GNHE5/5Uu7kw==@kvack.org X-Gm-Message-State: AOJu0YxxMq4+W1gP0k5+cMQ2tdvoQ6bbOaRjXNqSDkJf5tGF8s2xzVN1 mXwyVVvajPpT1iURPDGpcNUDRsOD596rhD89zM/1NdQPCL6UYcAEFiiiWdjumPapTnVwIUo9l1b ZH5BR5Zx4kew0i9oDLYb0BlsXtNPwR8hZ7FgbmoNT X-Gm-Gg: ASbGncsRCQsHEeGbWeKo0OL4qbUHUrCuCBdxaOoXa5cK5cC6EB4Br3LS2LkBkYua2P/ sF2G45GotGt9lF98BxThtSkxPfum6sk+Msy5mvjaw9Q3F5uDFuNhvv/sODQ9/58ahY64JtJnks1 ANJUGOHYEJJw9fWqmMDFsbfYsQnNucRCpJYYoCTIRFbgGLWhXcmboonKsPbJRqog2fkqeVu/WUB Wrgj+YCQy6y9pVvHa5YeHN4JMX7+P1CNDaUKilLcsLY X-Google-Smtp-Source: AGHT+IEpsuLg57KeWm89BZgtIm9RkiFt9/IvL1pt8dPdyEbMc9G1YFKO2IdV8XoDjVFZgzs9MuDgCYFK40OVoWDMZKk= X-Received: by 2002:a05:622a:55:b0:4b1:22f0:8016 with SMTP id d75a77b69052e-4b625170bbbmr869751cf.2.1757447293887; Tue, 09 Sep 2025 12:48:13 -0700 (PDT) MIME-Version: 1.0 References: <20250909065349.574894-1-liulei.rjpt@vivo.com> In-Reply-To: From: Suren Baghdasaryan Date: Tue, 9 Sep 2025 12:48:02 -0700 X-Gm-Features: AS18NWCnZI1Tq2lGwilQ5dvnko06eauIx4vwc90RQw36tzlJKEe_P08UvcGzo3g Message-ID: Subject: Re: [PATCH v0 0/2] mm: swap: Gather swap entries and batch async release To: Shakeel Butt Cc: Lei Liu , Michal Hocko , David Rientjes , Andrew Morton , Kemeng Shi , Kairui Song , Nhat Pham , Baoquan He , Barry Song , Chris Li , Johannes Weiner , Roman Gushchin , Muchun Song , David Hildenbrand , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Brendan Jackman , Zi Yan , "Peter Zijlstra (Intel)" , Chen Yu , Hao Jia , "Kirill A. Shutemov" , Usama Arif , Oleg Nesterov , Christian Brauner , Mateusz Guzik , Steven Rostedt , Andrii Nakryiko , Al Viro , Fushuai Wang , "open list:MEMORY MANAGEMENT - OOM KILLER" , open list , "open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)" Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 65A48C000E X-Stat-Signature: p8dfcqct4fgayqkiutzrgnnkggdpbeha X-Rspam-User: X-HE-Tag: 1757447295-392566 X-HE-Meta: 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 qUgaA2/e zLNLd2UOclm+q+qUM9yuGdGznPl9DtyGqHqY7mL5m9BIT9io1uqAeTuyskCEph0JhiXz5xMu1rrFP65VRjVT7CW/yGwsmXxcrNF+s87dxXcYGjEmTMIry1wIBmMGKaPllfCUdpLqNSOJMlvIciSoJhXWTDenDIrITbcDNkLUXRGOuXpCu0FVydZi2Ck87FC1baX2H 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 Tue, Sep 9, 2025 at 12:21=E2=80=AFPM Shakeel Butt wrote: > > On Tue, Sep 09, 2025 at 02:53:39PM +0800, Lei Liu wrote: > > 1. Problem Scenario > > On systems with ZRAM and swap enabled, simultaneous process exits creat= e > > contention. The primary bottleneck occurs during swap entry release > > operations, causing exiting processes to monopolize CPU resources. This > > leads to scheduling delays for high-priority processes. > > > > 2. Android Use Case > > During camera launch, LMKD terminates background processes to free memo= ry. > > How does LMKD trigger the kills? SIGKILL or cgroup.kill? SIGKILL > > > Exiting processes compete for CPU cycles, delaying the camera preview > > thread and causing visible stuttering - directly impacting user > > experience. > > Since the exit/kill is due to low memory situation, punting the memory > freeing to a low priority async mechanism will help in improving user > experience. Most probably the application (camera preview here) will get > into global reclaim and will compete for CPU with the async memory > freeing. > > What we really need is faster memory freeing and we should explore all > possible ways. As others suggested fix/improve the bottleneck in the > memory freeing path. In addition I think we should explore parallelizing > this as well. > > On Android, I suppose most of the memory is associated with single or > small set of processes and parallelizing memory freeing would be > challenging. BTW is LMKD using process_mrelease() to release the killed > process memory? Yes, LMKD has a reaper thread which wakes up and calls process_mrelease() after the main LMKD thread issued SIGKILL. >