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AJvYcCVia0jFmAPRSEhmYQ4UWNC36xWY5WlPzRBzVMao25wqXApKoa2xGc3x20r0FZFVCFeNbSMMRnHCaA==@kvack.org X-Gm-Message-State: AOJu0YxANg5DyO+B4suzCeVNIKaO1w8gZ6uOqXQAM1avvzc8Yk5Al5nU 9HOVsqAb5PY0DpmeFRhuomz3qT6INFFi4K+oF28DYjODI3gvBuTFmTmkOVhG+TZJoji5pxlSITN gRAtVlrruZnSMtcQdov09Nwdn1Q3utenujkHmAg0UaqDhCz+sm2pPOCWh8H5L16qMBn25i+UdWR wD/Qqn+2BrPmKoJN1ExirRs+4= X-Gm-Gg: ASbGncvDitkUOZSsGN7pWubQ9S9Nd6XAiToJ7MswGHJyrkoa8NZM7lYqdDFgYpWUzWR zG2nwQJ0/RCTyPxutl+7erNamjow092ZJz6CbfFySTf+3Ko2OS8fm1KxqQ2/hDWE8MWbti3KvaQ == X-Received: by 2002:a05:6e02:12c9:b0:3d1:4a69:e58f with SMTP id e9e14a558f8ab-3d58e81374emr209274365ab.2.1742891761225; Tue, 25 Mar 2025 01:36:01 -0700 (PDT) X-Google-Smtp-Source: AGHT+IF9E4/EucEBc/+iE2lWu+YyJiDtrud2DOWwH9Ttz3ALKtbFpsWVzZCuYuuSTYSC3OfYElupM2e2tE7hTWgAmd4= X-Received: by 2002:a05:6e02:12c9:b0:3d1:4a69:e58f with SMTP id e9e14a558f8ab-3d58e81374emr209274145ab.2.1742891760802; Tue, 25 Mar 2025 01:36:00 -0700 (PDT) MIME-Version: 1.0 References: <20250320015551.2157511-1-changyuanl@google.com> <20250320015551.2157511-12-changyuanl@google.com> In-Reply-To: From: Dave Young Date: Tue, 25 Mar 2025 16:36:22 +0800 X-Gm-Features: AQ5f1JqjFlzQ1M_D50CQArcQW8YwNNz0vfJYofXBEYquREvaq-g04uQRlGUrUgs Message-ID: Subject: Re: [PATCH v5 11/16] kexec: add config option for KHO To: Baoquan He Cc: Changyuan Lyu , linux-kernel@vger.kernel.org, graf@amazon.com, akpm@linux-foundation.org, luto@kernel.org, anthony.yznaga@oracle.com, arnd@arndb.de, ashish.kalra@amd.com, benh@kernel.crashing.org, bp@alien8.de, catalin.marinas@arm.com, dave.hansen@linux.intel.com, dwmw2@infradead.org, ebiederm@xmission.com, mingo@redhat.com, jgowans@amazon.com, corbet@lwn.net, krzk@kernel.org, rppt@kernel.org, mark.rutland@arm.com, pbonzini@redhat.com, pasha.tatashin@soleen.com, hpa@zytor.com, peterz@infradead.org, ptyadav@amazon.de, robh+dt@kernel.org, robh@kernel.org, saravanak@google.com, skinsburskii@linux.microsoft.com, rostedt@goodmis.org, tglx@linutronix.de, thomas.lendacky@amd.com, usama.arif@bytedance.com, will@kernel.org, devicetree@vger.kernel.org, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: I5JvezAUVQFCvKbpUGkyEioRsrB_Xy1ud1dfFInG9NE_1742891761 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: A7ADF140004 X-Stat-Signature: d9b8pkrfdffqzcgsgt3radsuab8wjnes X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1742891764-776924 X-HE-Meta: U2FsdGVkX1/grmQ49QD4FHFyqdZHj5mg+p/E4pReNnpUWlo0GB9JuezvcmGTycgTToPH/GanuOOEBGNmGBYq1V+Uc4vTbIfco6dazSejIwKi6cDLmY/BdTGN4ahph4PmpXQe1RbcoWg9mI06FUMjl3OUUbqdltFFFnIPgaV+lOu8jebNHdxe/izgdyHBVcKYENh5Dqvv/mVL92gQtS8WBzeXSu+2CuDYyQZ9wmSMeaJ+tpLVPbIYm6TLj2QroUCsEs2VoocaUv04d3qQA+WhUsnBAk464vpdzOcvMx7mwvPpgKhXQmMCs+Jum7mk7VU52stpwiqEykQMFLZwxYVISfuA4djElXosAgFHKtqjbxzI5fsLRdB1C5LBkvIOeuT8mVhldmXIWuuC4lwfsDaafaqAMbtr+692SVQhDbinZ6Xe1EU1vwp9Z9gcU2dgBdM33Vf41a0tXdEShcIGDzyhQbO3j1QZlvgUvnbLivk57IdbnrBmOwDFPloaLOnNioLgag6YavwDGoGKaVB9T+EwahL8ExW9fOtBpXPkywDsE1BagrkvDt70uFI6vRdxMFpD/Fla5ortAdLrFtZtQJjLCZoPFGdm6vxSJjzrPjZl9e+rm25Z84OjePqee+ZGvHBlzHNwfeHwhk1TVRJ6jV5HApDPv7bqEVXKNLzscI8LtwNYcd8xst14QAZel+ScdcWp1CtZXSwW4ceuoJX7p8x/HShC9QC5lSstOu4XLY7xkZZ9fEoNsDOvlySySe3LD7GeF6G2WJI4zOWjDWVP0eTwWI36Ii0ErDrcjRLwiflTeicd3qQgjqBhRi7pu+B38IMkNKLQdpvonbd8lGw+vZzVWN+K8uDbof8HPWhvZsp5evWO2B5HIn/PKTL37lxswTARdB+wQuFz1ITZzJv0E5u61WgYXYtlrro7MWSGOy8eHXfCBtEV0JQXblJRMW1v89k5xaNeNRNftchvp2hIeCm wjuXdmpi IEWYwHNWddTTHHtPEgtDEXkHeJIkNaIUkvEPWVTdHT+2Zn/Z6FGBmucJ7nPwp+HKCoM1eiqaBv/UOwr8Wz5vRAwnk/Pmj7S8fuGaCzyYlg6uZSjRTCRmuhAfkZ/huzGJhyqnkSZIoNA9fGtmXzbY4F/abhg== 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: > > > > Have you tested kdump? In my mind there are two issues, one is with > > CMA enabled, it could cause kdump crashkernel memory reservation > > failures more often due to the fragmented low memory. Secondly, in > > kho scracth memorys are reserved much later than crashkernel, we may not > need to worry about it. > ==================== > start_kernel() > ...... > -->setup_arch(&command_line); > -->arch_reserve_crashkernel(); > ...... > -->mm_core_init(); > -->kho_memory_init(); > > > kdump kernel dump the crazy scratch memory in vmcore is not very > > meaningful. Otherwise I suspect this is not tested under kdump. If > > so please disable this option for kdump. Ok, it is fine if this is the case, thanks Baoquan for clearing this worry. But the other concerns are still need to address, eg. KHO use cases are not good for kdump. There could be more to think about. eg. the issues talked in thread: https://lore.kernel.org/lkml/Z7dc9Cd8KX3b_brB@dwarf.suse.cz/T/