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[213.151.95.130]) by smtp.gmail.com with ESMTPSA id x132sm5878901wmg.0.2019.12.18.02.17.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Dec 2019 02:17:12 -0800 (PST) Date: Wed, 18 Dec 2019 11:17:11 +0100 From: Michal Hocko To: John Hubbard Cc: "Michael Kerrisk (man-pages)" , Yang Shi , cl@linux.com, cai@lca.pw, akpm@linux-foundation.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] move_pages.2: not return ENOENT if the page are already on the target nodes Message-ID: <20191218101711.GB21485@dhcp22.suse.cz> References: <1575596090-115377-1-git-send-email-yang.shi@linux.alibaba.com> <0dc96e40-5f2b-a2fe-6e5f-b6f3d5e9ebde@nvidia.com> <95170ea5-5b62-9168-fcd9-93b43330a1b4@linux.alibaba.com> <092adc11-7039-9343-7067-0e0199c9dc13@gmail.com> <51dd767a-221f-882d-c7f6-45bd0c217a67@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51dd767a-221f-882d-c7f6-45bd0c217a67@nvidia.com> User-Agent: Mutt/1.12.2 (2019-09-21) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue 17-12-19 23:36:09, John Hubbard wrote: [...] > diff --git a/man2/move_pages.2 b/man2/move_pages.2 > index 2d96468fa..1bf1053f2 100644 > --- a/man2/move_pages.2 > +++ b/man2/move_pages.2 > @@ -191,12 +191,6 @@ was specified or an attempt was made to migrate pages of a kernel thread. > .B ENODEV > One of the target nodes is not online. > .TP > -.B ENOENT > -No pages were found that require moving. > -All pages are either already > -on the target node, not present, had an invalid address or could not be > -moved because they were mapped by multiple processes. > -.TP > .B EPERM > The caller specified > .B MPOL_MF_MOVE_ALL > > ...But I'm not sure if we should change the implementation, instead, so > that it *can* return ENOENT. That's the main question to resolve before > creating any more patches, I think. I would start by dropping any note about ENOENT first. I am not really sure there is a reasonable usecase for it but maybe somebody comes up with something and only then we should consider it. Feel free to add Acked-by: Michal Hocko ideally with a kernel commit which removed the ENOENT. -- Michal Hocko SUSE Labs