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AJvYcCXlov7OSM+NRMPz0MdCFN+ZPLQTW+01Bp5b74+PY+arsbmhJM6ssfqPT1yNyjcsenJM51j5Bw3cI5nXNc1VaYAWjL4= X-Gm-Message-State: AOJu0YwUSRVg2TxdtVKlH7hmwzkcAIvenb44IBKyddSCiY+15EEKPee3 z4q2UlICTlqbwSY24Evxgl5sl10IsmltrCc90WJkNaJXfDaMO5dLb106j/QIIzPuxgOENLjND02 x/aRngFV84vuqfhdUqjbqlvlMeJw= X-Google-Smtp-Source: AGHT+IF4m3dgoSMmOTM4bk0KoXHGseYv3UMy+OTOQ+OvzblAw7CY3DMgupyPNvuJ3tBg+ruYSxeWUDP5FHgbfoGuQEc= X-Received: by 2002:a05:6102:3751:b0:470:40f1:a185 with SMTP id u17-20020a056102375100b0047040f1a185mr7266227vst.13.1708413379290; Mon, 19 Feb 2024 23:16:19 -0800 (PST) MIME-Version: 1.0 References: <20240219141703.3851-1-lipeifeng@oppo.com> <20240219141703.3851-2-lipeifeng@oppo.com> <7c648dac-3198-3dba-0a96-34798cfdbd99@oppo.com> <8ea640a1-fc2c-a6fa-cf4b-bb8c0b694b4f@oppo.com> In-Reply-To: <8ea640a1-fc2c-a6fa-cf4b-bb8c0b694b4f@oppo.com> From: Barry Song <21cnbao@gmail.com> Date: Tue, 20 Feb 2024 20:16:08 +1300 Message-ID: Subject: Re: [PATCH 1/2] mm/rmap: support folio_referenced to control if try_lock in rmap_walk To: =?UTF-8?B?5p2O5Z+56ZSL?= Cc: akpm@linux-foundation.org, david@redhat.com, osalvador@suse.de, willy@infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, tkjos@google.com, surenb@google.com, gregkh@google.com, v-songbaohua@oppo.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 3ADBB100003 X-Rspam-User: X-Rspamd-Server: rspam11 X-Stat-Signature: k7dgnhoqtbfekzja5a6k4z1d31w57hah X-HE-Tag: 1708413380-525668 X-HE-Meta: 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 tSy/4iVs mYvuVxv/L4YpehsXnpDEEMl6JfQEzUbvvkFDZavrDfEErf5dZ9e+aBssoaPCSBqYfXv6wXRy5kKQR/SQ= X-Bogosity: Ham, tests=bogofilter, spamicity=0.262861, 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, Feb 20, 2024 at 5:00=E2=80=AFPM =E6=9D=8E=E5=9F=B9=E9=94=8B wrote: > > > =E5=9C=A8 2024/2/20 11:01, Barry Song =E5=86=99=E9=81=93: > > Hi peifeng, > > > > On Tue, Feb 20, 2024 at 2:43=E2=80=AFPM =E6=9D=8E=E5=9F=B9=E9=94=8B wrote: > >> add more experts from Linux and Google. > >> > >> > >> =E5=9C=A8 2024/2/19 22:17, lipeifeng@oppo.com =E5=86=99=E9=81=93: > >>> From: lipeifeng > >>> > >>> The patch to support folio_referenced to control the bevavior > >>> of walk_rmap, which for some thread to hold the lock in rmap_walk > >>> instead of try_lock when using folio_referenced. > > please describe what problem the patch is trying to address, > > and why this modification is needed in commit message. > > Hi Barry=EF=BC=9A > > 1. the patch is one of the kshrinkd series patches. this seems like a bad name for the patchset as nobody knows what is kshrinkd. maybe something like "asynchronously reclaim contended folios rather than aging them"? > > 2. it is to support folio_referenced to control the bevavior of walk_rmap= , > > kshrinkd would call folio_referenced through shrink_folio_list but it > doesn't > > want to try_lock in rmap_walk during folio_referenced. > > > > btw, who is set rw_try_lock to 0, what is the benefit? > > Actually, the current situation is that only shrink_folio_list will set > try_lock to 1=EF=BC=8C understood, as you don't want contended folios to be skipped by scanner any more. > > while others will be set to 0 that it would wait for rwsem-lock if > contened in rmap_walk. ok. other reclamation threads will still skip contended folios. As discussed, the patchset really needs detailed data to back up. Thanks Barry