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[71.184.117.43]) by smtp.gmail.com with ESMTPSA id p3sm6001073qkf.107.2019.12.06.10.00.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 06 Dec 2019 10:00:20 -0800 (PST) Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable From: Qian Cai Mime-Version: 1.0 (1.0) Subject: Re: [PATCH] move_pages.2: not return ENOENT if the page are already on the target nodes Date: Fri, 6 Dec 2019 13:00:18 -0500 Message-Id: References: <5384814f-c937-9622-adbe-c03e199e0267@linux.alibaba.com> Cc: Michal Hocko , John Hubbard , mtk.manpages@gmail.com, cl@linux.com, akpm@linux-foundation.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org In-Reply-To: <5384814f-c937-9622-adbe-c03e199e0267@linux.alibaba.com> To: Yang Shi X-Mailer: iPhone Mail (17B111) 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: > On Dec 6, 2019, at 12:31 PM, Yang Shi wrote: >=20 > It looks since commit e78bbfa82624 ("mm: stop returning -ENOENT from sys_m= ove_pages() if nothing got migrated") too, which reset err to 0 unconditiona= lly. It seems it is on purpose by that commit the syscall caller should chec= k status for the details according to the commit log. I don=E2=80=99t read it on purpose. =E2=80=9CThere is no point in returning -= ENOENT from sys_move_pages() if all pages were already on the right node=E2=80=9D, so this is only taking about the pa= ges in the desired node. Anyway, but now it is probably the best time to thi= nk outside the box redesigning this syscalls and nuke this whole mess.=