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Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20250918071741.526280-1-ye.liu@linux.dev> <1a9f44a1-855c-450e-9dc4-415a29b90011@linux.dev> <780aa9d6-a85c-4050-820e-c0ca9f5bb658@redhat.com> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Ye Liu In-Reply-To: <780aa9d6-a85c-4050-820e-c0ca9f5bb658@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspamd-Queue-Id: 283A31C0004 X-Rspam-User: X-Rspamd-Server: rspam07 X-Stat-Signature: wrkmd9y61nesuzkr6qggecwzogmpnddd X-HE-Tag: 1758184291-355667 X-HE-Meta: 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 gA9bFijC ylL1qnZJ4toBirVpxwW1Bgd5Ap6KZYBKoNdV0iymZd0bfMqKZb0FzfOoEHeaj05rHtaMJREIvT+Q+twZ7BlZrxxdxkiAwa86uoHerBVBZngbt/6GdOFfsVemtJYU3R48fwy4bW4Feh2nlj6rX0QxNGhym49MAbsEL3u5Vqc5pghvMVIWZJkv5ZaKefWgaPyi/Sg1a+IyMdVl7bK0IQm4I/cxO0fLuc66ZrqRqJtjb7e94n5Y= 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: List-Subscribe: List-Unsubscribe: 在 2025/9/18 16:16, David Hildenbrand 写道: > On 18.09.25 10:11, Ye Liu wrote: >> >> >> 在 2025/9/18 15:29, Michal Hocko 写道: >>> On Thu 18-09-25 15:17:40, Ye Liu wrote: >>>> From: Ye Liu >>>> >>>> Add a header line to /proc/buddyinfo that shows the order numbers >>>> for better readability and clarity. >>>> >>>> Before: >>>> Node 0, zone      DMA      0      0      0      0      0      0      0 ... >>>> Node 0, zone    DMA32      5      8      6      6      7      5      8 ... >>>> Node 0, zone   Normal   1113    351    138     65     38     31     25 ... >>>> >>>> After: >>>> Free pages per order       0      1      2      3      4      5      6 ... >>>> Node 0, zone      DMA      0      0      0      0      0      0      0 ... >>>> Node 0, zone    DMA32      5      8      6      6      7      5      8 ... >>>> Node 0, zone   Normal   1113    351    138     65     38     31     25 ... >>> >>> Why is this needed? And have you considered tha this might break >>> existing parsers of the file? >>> >> >> Thanks for the review. >> >> The reason for this change is simply to make /proc/buddyinfo self-describing. >> Right now you have to know which column is which order; with a header it’s >> obvious. This is similar to what /proc/pagetypeinfo already does, e.g.: >> >>    Page block order: 9 >>    Pages per block: 512 >> >>    Free pages count per migrate type at order   0 1 2 3 ... >>    Node 0, zone DMA, type Unmovable             0 0 0 ... >> >> Regarding existing parsers: the patch does not change any of the existing >> “Node … zone …” lines, it only adds a single header line before them. Most >> parsers match “Node” lines and ignore everything else, so the risk should be >> low. If you know of any existing parser that this would break, please let >> me know so I can address it. > > What if there is a single one out there that has hardcoded to skip the first line only? I understand there may be no way to be fully compatible with all existing parsers. However, /proc/buddyinfo is essentially raw data intended for human and tool consumption, and parsers are expected to be robust against format changes. Adding a '#' prefix to the header would allow most parsers to skip it, but it still changes the file output and cannot fully guarantee that no external tool will be affected. > -- Thanks, Ye Liu