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Fri, 03 Apr 2026 10:24:46 -0700 (PDT) MIME-Version: 1.0 References: <20260323235817.1960573-1-dmatlack@google.com> <20260323235817.1960573-3-dmatlack@google.com> In-Reply-To: From: Chris Li Date: Fri, 3 Apr 2026 10:24:35 -0700 X-Gmail-Original-Message-ID: X-Gm-Features: AQROBzDLi9Fnv8_mDDwmklVKEby5KKVysrnsYTweXxYMFegWZQjyvtyGp9AI6Cw Message-ID: Subject: Re: [PATCH v3 02/24] PCI: Add API to track PCI devices preserved across Live Update To: "Yanjun.Zhu" Cc: David Matlack , Alex Williamson , Bjorn Helgaas , Adithya Jayachandran , Alexander Graf , Alex Mastro , Andrew Morton , Ankit Agrawal , Arnd Bergmann , Askar Safin , "Borislav Petkov (AMD)" , Dapeng Mi , David Rientjes , Feng Tang , Jacob Pan , Jason Gunthorpe , Jason Gunthorpe , Jonathan Corbet , Josh Hilke , Kees Cook , Kevin Tian , kexec@lists.infradead.org, kvm@vger.kernel.org, Leon Romanovsky , Leon Romanovsky , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org, linux-pci@vger.kernel.org, Li RongQing , Lukas Wunner , Marco Elver , =?UTF-8?Q?Micha=C5=82_Winiarski?= , Mike Rapoport , Parav Pandit , Pasha Tatashin , "Paul E. McKenney" , Pawan Gupta , "Peter Zijlstra (Intel)" , Pranjal Shrivastava , Pratyush Yadav , Raghavendra Rao Ananta , Randy Dunlap , Rodrigo Vivi , Saeed Mahameed , Samiullah Khawaja , Shuah Khan , Vipin Sharma , Vivek Kasireddy , William Tu , Yi Liu Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: B528D140005 X-Stat-Signature: w6uqejz7ibunfcwisczie7e94o3g6hj3 X-Rspam-User: X-Rspamd-Server: rspam04 X-HE-Tag: 1775237088-895693 X-HE-Meta: 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 6S9ESHCX CCZ4RXuJkm1i6ydVgUPK/4QEpdoJje0KxZ3GMnN5AlWq0M/1Hl2Cb3KT+AiPIcJHk/6Vco56tsB6Qi2qfbHZdZ1G78TMEMNpfCC43mNNFbsVXZsLodJLDE/CJ8JDe7qsuPEYcTTuA889SDuyC4XPGlmfkqaSsrgE2UlJguJ6DkZAqH+KwbM5iGrF/AEmLpYNBnOmybvua60dtbmvXl04if9sAq6cELME/q3j3SFoyPJF8ol57D3bwOGhlRC/xKMqaG5SojLin4ZMmLCGPTGB/RV8/oY9kfZNEmN8F Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Apr 2, 2026 at 2:29=E2=80=AFPM Yanjun.Zhu wr= ote: > > +config PCI_LIVEUPDATE > > + bool "PCI Live Update Support (EXPERIMENTAL)" > > + depends on PCI && LIVEUPDATE > > + help > > + Support for preserving PCI devices across a Live Update. This o= ption > > + should only be enabled by developers working on implementing th= is > > + support. Once enough support as landed in the kernel, this opti= on > > + will no longer be marked EXPERIMENTAL. > > + > > + If unsure, say N. > > Currently, it only supports 'n' or 'y'. Is it possible to add 'm' > (modular support)? > > This would allow the feature to be built as a kernel module. For > development > > purposes, modularization means we only need to recompile a single module > > for testing, rather than rebuilding the entire kernel. Compiling a > module should > > be significantly faster than a full kernel build. Building as a module has extra complexity to handle, e.g. the callback can happen when the module hasn't been loaded. Then the user space can take an arbitrarily long time to load the module. It needs more infrastructure to support the liveupdate as a module. Chris