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b=MKFzGvSFZwWIFFRA0ZXyvs16A8suXF5CnHj8Yu6DWVn1XNaXrMDEdixojJ9WmXEb7 B8HFMUjzOTvU6RwlNQjwdzjqPDvQCGA/4AJ0Em0zHhj4ypRhnI0mKxzYLZP1OV0ifL eA9/fxW3Pxy16892wCazYquUCYCuIsm8XcchNAPA4t/tkQu4javpgOcU7RVq4A3nxo k4uHK/8yLyZ3smraijDdggziz20OX07t14xfVyqW5GBbR1PgqbbVWyHXUI4Z32Xbrc 0iyAWtnR+xfX5UnU/tie3OAW89SLmVQEk/G3YHRAs2N39oS4qhXV1enxnkV6a1AaEm jVNdWp25bMNnQ== Date: Sun, 8 Nov 2026 10:14:46 +0200 From: Mike Rapoport To: Huacai Chen Cc: George Guo , pasha.tatashin@soleen.com, pratyush@kernel.org, ardb@kernel.org, shuah@kernel.org, ilias.apalodimas@linaro.org, akpm@linux-foundation.org, baoquan.he@linux.dev, ruirui.yang@linux.dev, guodongtai@kylinos.cn, kernel@xen0n.name, graf@amazon.com, liukexin@kylinos.cn, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-efi@vger.kernel.org Subject: Re: [PATCH v6 5/8] LoongArch: Allow memblock arrays to resize Message-ID: References: <20261029172956.20791-1-dongtai.guo@linux.dev> <20261029172956.20791-6-dongtai.guo@linux.dev> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Stat-Signature: xy6ci5z6owh9xycqgsayore1fyqi1qje X-Rspamd-Queue-Id: 89B7840002 X-Rspam-User: X-Rspamd-Server: rspam08 X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-HE-Tag: 1794125697-31437 X-HE-Meta: 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 uZNsTYIQ w6QAKX8t1crc+RiQxJXDi2eh95psUqLYi68Pfh6ROAhF141Gv0BPpcsRIUyxBfqEH90KLZte7ozezEb5Z2wijlWnxP+oVlCIaqn6vKa9Oc541Yce4jaZFvJ0JChWigDPHHwQG/AcJ6hh1S2SidryKfbEBZ+23/9LAODVp3k/2RYaD8jl2kDW3KR2ONb99PfLE7KniDrq061YaCDoyyo3L4HSuQaLDC1GioaKqofOVxkKmJJVHq84oYQgKsrAGR1k6tLJyf3b4EtoVQb0WHkWkjGVAQWBhCiGRh0I3u2kjuYVhNxM= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Fri, Nov 06, 2026 at 10:35:01PM +0800, Huacai Chen wrote: > On Fri, Nov 6, 2026 at 12:07 AM Mike Rapoport wrote: > > > > On Thu, Nov 05, 2026 at 11:07:01PM +0800, Huacai Chen wrote: > > > Hi, Mike, > > > > > > On Thu, Nov 5, 2026 at 8:57 PM Mike Rapoport wrote: > > > > > > > > On Fri, Oct 30, 2026 at 02:29:52AM +0900, George Guo wrote: > > > > > From: George Guo > > > > > > > > > > LoongArch never calls memblock_allow_resize(), so the reserved region > > > > > array cannot grow beyond INIT_MEMBLOCK_RESERVED_REGIONS entries > > > > > (INIT_MEMBLOCK_REGIONS + NR_CPUS). > > > > > > > > This might be something to fix independent of KHO. > > > > > > > > Huacai, > > > > > > > > What's the reason LoongArch never enables memblock resizing and why it > > > > defines INIT_MEMBLOCK_RESERVED_REGIONS to include NR_CPUS? > > > At first we didn't define INIT_MEMBLOCK_RESERVED_REGIONS, then we got > > > boot failures on a 128-cores machine, so define it, and the value is > > > similar to arm64. > > > > AFAIR, arm64 had to reserve some per cpu data before they could enable > > memblock resizing, so they had to make it static. > LoongArch is similar, so below 64-cores machine has no problem. > > > > > > The reason LoongArch never enables memblock resizing is because the mm > > > code is derived from MIPS, and MIPS never enables it. > > > > If that's the only reason, you might want to revisit that :) > Yes, it seems we need memblock_allow_resize(), but maybe it is better > to bring back paging_init()? Most other archs call > memblock_allow_resize() in paging_init(). paging_init() is a historical relict that hugely misnamed everywhere :) I think platform_init() should be fine. As far as I can tell, by the time platform_init() calls init_numa_memory(), all memory reservations that must happen before any memblock allocations are done. > Huacai -- Sincerely yours, Mike.