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charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 52FB71C001C X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: 8w1f9qrhp8qjuj9uiwnsoijpyt57q9w6 X-HE-Tag: 1700815044-256827 X-HE-Meta: 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 j0XpiF7q UrGfafEXJ8sPYsMWrxrqZM7DBuxdG4Zq0y5z9rDA3D5ldPdRZjvWjYFGJLeMM/PTsNf85KmM7jiV6G90yIJIMChLesO/cm7ouPDbADfdM1/XrdKAfXZ2kpF9HzPseXQNbpJGyQWTTKES+Rrv+bdZJfXsNh/QRHJMX2D5kFRUOQCZc1zBYstM8acn+WbB4jovoqIWNHu8d9vJhSICsdMEN7OOETae/MHEjPecwIioicuI1ufaqHlv7Gd8300LgCOqrX3lCktxKrep7ad+hxMbM+2qjRXFf40zuZyLjT0Fpnk18HNbhJDjCId/dRGDE/RyXgzkzDbkP8RANkF2aumloxKMYHbl6/kY59FIgHvKDQ5DevUPTVAqQgWV08UP9s+tv1QyhgRLZajYePg8= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000028, 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 Fri, Nov 24, 2023 at 12:15=E2=80=AFAM Kairui Song wro= te: > > > folio_put will discharge a page if it's charged, in original code the > 2 folio_put call simply free the page since it's not charged. But in > this patch, folio_put will cancel previous > mem_cgroup_swapin_charge_folio call, so actually the 3 > mem_cgroup_swapin_charge_folio calls will only charge once. (2 calls > was cancelled by folio_put). You are saying the original code case folio_put() will be free without uncharge. But with your patch folio_put() will free and cancel mem_cgroup_swapin_charge_folio() charge. That is because the folio->memcg_data was not set in the first case and folio->memcg_data was set in the second case? > > I think this is making it confusing indeed and causing more trouble in > error path (the uncharge could be more expensive than unlock check), > will rework this part. Agree. Thanks. Chris