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b=bKWIpJroWZmQuSMKmkcHkS+KBMrgb1w1jTz5HKzXIOr50CEf78uf0IDuq69Df3xiG McCrtoOIvk0xb6p6wbnwjGvzKd6b6pyVQf4nKgBFJap0yATUxKBBuOYv3hAxPCo9+z 5piNj6JnHodsMU9py/wzB+LPq7CLnzXj5WQz0Bj42hex+bec+bW9zqWjC7hrHRS2IJ tlvXHJC7RxLi3+LmQyX6yRcwvcx28ds5CuCBBa4/hScO7VelF15BopQikaxNJn608s 0vUMHKv70OmXy28yj7eKHQK9jOI7XNRssHsj8OdrzqaI+XX28zWZTY9aH9cN7yI7GJ 05o1Esz3NWV3w== Date: Wed, 4 Nov 2026 18:50:04 +0200 From: Mike Rapoport To: Pasha Tatashin Cc: Pratyush Yadav , Alexander Graf , Andrew Morton , Chen Pei , George Guo , Kexin Liu , Sourabh Jain , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/2] kho: skip zero-sized lowmem and global bootmem areas Message-ID: References: <20261103-kho-bootmem-sizing-v1-0-45aa74098f34@kernel.org> <20261103-kho-bootmem-sizing-v1-1-45aa74098f34@kernel.org> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: 54hhxqba8cst7ith3q7z1t1uodnmtubm X-Rspamd-Queue-Id: 718BFC0006 X-Rspam-User: X-Rspamd-Server: rspam08 X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=unavailable autolearn_force=no version=4.0.1 X-HE-Tag: 1793811011-259647 X-HE-Meta: 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 X5YWVUEt ZutTgxUk9/T8wRNCOTJ9kJ4Hm8ayAfyzKC5DnAuYlXC9HMFUdVFx8PmCkWaLRpb92DI/o4sdk4fRupZOAmtkChMuq614bC+UaPOoZriBf5PWWpUcEtKPkVTVyU2B8rJ4GB6GiJuGjMk9s4FK6ex1R1LQecn1298R+ImFbYRbd3Daj8WFddjosR7uRl+ddimTBkXCJkuvV6hFMIe/QNvALGDVtipZzS2u4YgBnzir902WTXCFkZv1Ei5aHvNZ/2BBhsQfa 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 Wed, Nov 04, 2026 at 10:32:14AM -0500, Pasha Tatashin wrote: > On 11-04 13:22, Mike Rapoport wrote: > > On Tue, Nov 03, 2026 at 02:48:36PM -0500, Pasha Tatashin wrote: > > > > @@ -852,56 +873,32 @@ static void __init kho_reserve_bootmem(void) > > > > * reserve bootmem area in low memory for lowmem allocations in the > > > > * next kernel > > > > */ > > > > - size = bootmem_size_lowmem; > > > > - addr = memblock_phys_alloc_range(size, BOOTMEM_ALIGNMENT_BYTES, 0, > > > > - ARCH_LOW_ADDRESS_LIMIT); > > > > - if (!addr) { > > > > + if (kho_reserve_bootmem_area(&i, bootmem_size_lowmem, > > > > + ARCH_LOW_ADDRESS_LIMIT, NUMA_NO_NODE)) { > > > > pr_err("Failed to reserve lowmem bootmem\n"); > > > > > > You are adding a helper that returns an error code and then ignoring it > > > at all call sites. Even though it can only return -ENOMEM right now, > > > dropping the return value is not good practice. > > > > I don't think error code is important here. > > Perhaps, but it is just not elegant to add a function that returns an > error, call that function from three places, and ignore that error every > time. Because it's not important what the error was. > What is wrong with: > > err = kho_reserve_bootmem_area(...); > if (err) { > pr_err("Failed to reserve lowmem bootmem: %pe\n", ERR_PTR(err)); > ... > } More churn for no value? > -- > Pasha -- Sincerely yours, Mike.