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Thu, 14 Sep 2023 15:47:48 -0700 (PDT) MIME-Version: 1.0 References: <20230913173000.4016218-1-souravpanda@google.com> <20230913173000.4016218-2-souravpanda@google.com> <5d6a780e-2945-2b24-bca6-3e38565fe157@redhat.com> In-Reply-To: <5d6a780e-2945-2b24-bca6-3e38565fe157@redhat.com> From: Sourav Panda Date: Thu, 14 Sep 2023 15:47:37 -0700 Message-ID: Subject: Re: [PATCH v1 1/1] mm: report per-page metadata information To: David Hildenbrand Cc: corbet@lwn.net, gregkh@linuxfoundation.org, rafael@kernel.org, akpm@linux-foundation.org, mike.kravetz@oracle.com, muchun.song@linux.dev, rppt@kernel.org, rdunlap@infradead.org, chenlinxuan@uniontech.com, yang.yang29@zte.com.cn, tomas.mudrunka@gmail.com, bhelgaas@google.com, ivan@cloudflare.com, pasha.tatashin@soleen.com, yosryahmed@google.com, hannes@cmpxchg.org, shakeelb@google.com, kirill.shutemov@linux.intel.com, wangkefeng.wang@huawei.com, adobriyan@gmail.com, vbabka@suse.cz, Liam.Howlett@oracle.com, surenb@google.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org Content-Type: multipart/alternative; boundary="0000000000001a406806055977af" X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: A4B1B140003 X-Stat-Signature: ofqaxd8zompbt7disrbbci6fb753pahm X-Rspam-User: X-HE-Tag: 1694731669-647702 X-HE-Meta: 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 Gk63T2Hj NEjvmLbW4Z6a+/VqLp+yZSAuuunrF1281OMUKKcvoMesmW5Euf3P/BJrBL23hJUpZJYSI8qnvuthTunDWWrBJqPhg5djnPiWj3btTyyOgo4aOo2HfPvu0luyXa+RhhAoTHkOfXGIuvNEfSyOtAgSRAtqF0SYlS621fqfGLJRPty/ZZs6RcBQaEynHGD5z7JWxHow8NCkBIbk7ztJc+Zk2o9ibPgOuc04qpgjNYkmLreMYsB8KCMVm9bO0OOn2aWp5VkWYABTitMt9QIBcoKr+GwVnvNFNWAh0CwDWkyfuOqAc0aP/R5dQ0esEO1UA0GmPvuhKGRgzU6ikzCLTehMdp1OVIoQoa4fttvwJL6b5fNNKnmUNY0LSjgAADaY1jojOUuIkzEMB3Ztt8Str7LG3ZAUGmiSsx6irNHBjIw/T1zxBuHs= 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: --0000000000001a406806055977af Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Thank you David Hildenbrand for reviewing this patch. On Thu, Sep 14, 2023 at 6:00=E2=80=AFAM David Hildenbrand wrote: > On 13.09.23 19:30, Sourav Panda wrote: > > Adds a new per-node PageMetadata field to > > /sys/devices/system/node/nodeN/meminfo > > and a global PageMetadata field to /proc/meminfo. This information can > > be used by users to see how much memory is being used by per-page > > metadata, which can vary depending on build configuration, machine > > architecture, and system use. > > > > Per-page metadata is the amount of memory that Linux needs in order to > > manage memory at the page granularity. The majority of such memory is > > used by "struct page" and "page_ext" data structures. > > It's probably worth mentioning, that in contrast to most other "memory > consumption" statistics, this metadata might not be included "MemTotal"; > when the memmap is allocated using the memblock allocator, it's not > included, when it's dynamically allocated using the buddy (e.g., memory > hotplug), it's included. > > Thank you for your comment, Completely agree with you and shall make this change. --0000000000001a406806055977af Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Thank you David Hildenbrand for reviewing=C2=A0this p= atch.=C2=A0

On Thu, Sep 14, 2023 at 6:00=E2=80=AFAM David Hildenb= rand <david@redhat.com> wrote= :
On 13.09.23 19= :30, Sourav Panda wrote:
> Adds a new per-node PageMetadata field to
> /sys/devices/system/node/nodeN/meminfo
> and a global PageMetadata field to /proc/meminfo. This information can=
> be used by users to see how much memory is being used by per-page
> metadata, which can vary depending on build configuration, machine
> architecture, and system use.
>
> Per-page metadata is the amount of memory that Linux needs in order to=
> manage memory at the page granularity. The majority of such memory is<= br> > used by "struct page" and "page_ext" data structur= es.

It's probably worth mentioning, that in contrast to most other "me= mory
consumption" statistics, this metadata might not be included "Mem= Total";
when the memmap is allocated using the memblock allocator, it's not included, when it's dynamically allocated using the buddy (e.g., memory=
hotplug), it's included.


Thank you for your comment, Completely= agree with you and shall make this change.
--0000000000001a406806055977af--