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([2600:1700:dac0:2450::38]) by smtp.gmail.com with ESMTPSA id s26sm4028031otk.43.2019.12.13.17.55.16 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 13 Dec 2019 17:55:19 -0800 (PST) Cc: mtk.manpages@gmail.com, 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 To: Yang Shi , John Hubbard , cl@linux.com, mhocko@suse.com, cai@lca.pw, akpm@linux-foundation.org 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> From: "Michael Kerrisk (man-pages)" Message-ID: <092adc11-7039-9343-7067-0e0199c9dc13@gmail.com> Date: Sat, 14 Dec 2019 02:55:15 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <95170ea5-5b62-9168-fcd9-93b43330a1b4@linux.alibaba.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-man-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org On 12/6/19 6:26 PM, Yang Shi wrote: > > > On 12/6/19 12:25 AM, John Hubbard wrote: >> On 12/5/19 5:34 PM, Yang Shi wrote: >>> Since commit e78bbfa82624 ("mm: stop returning -ENOENT >>> from sys_move_pages() if nothing got migrated"), move_pages doesn't >>> return -ENOENT anymore if the pages are already on the target nodes, but >>> this change is never reflected in manpage. >>> >>> Cc: Michael Kerrisk >>> Cc: Christoph Lameter >>> Cc: John Hubbard >>> Cc: Michal Hocko >>> Cc: Qian Cai >>> Signed-off-by: Yang Shi >>> --- >>>   man2/move_pages.2 | 5 ++--- >>>   1 file changed, 2 insertions(+), 3 deletions(-) >>> >>> diff --git a/man2/move_pages.2 b/man2/move_pages.2 >>> index 2d96468..2a2f3cd 100644 >>> --- a/man2/move_pages.2 >>> +++ b/man2/move_pages.2 >>> @@ -192,9 +192,8 @@ was specified or an attempt was made to migrate >>> pages of a kernel thread. >>>   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 >>> +No pages were found. >>> +All pages are either not present, had an invalid address or could >>> not be >>>   moved because they were mapped by multiple processes. >>>   .TP >>>   .B EPERM >>> >> >> whoa, hold on. If I'm reading through the various error paths >> correctly, then this >> code is *never* going to return ENOENT for the whole function. It can >> fill in that >> value per-page, in the status array, but that's all. Did I get that >> right? > > Nice catch. Yes, you are right. > >> >> If so, we need to redo this part of the man page. > > Yes. So where are things at with this? Is an improved man-pages patch on the way, or is some other action (on the API) planned? Thanks, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/