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b=C6gjVPPdP/VVRhfNC+VDHXi2GkriaQ59zF9dvrRLavOayKedKO5VbJRufDpzaSKcT 18Yctoq4Bqz+A3ymRbCPtfV0a8OX0gaSH+Bm6w4VQzsKXgtFzCgKm5ydaL5PtJQ29h tAfGWpMBVJbutynfBiW2hC33t3Pjdnc9gI26HN9BHIfQdB+IRyFb8YI4OTAELjHoms YU3d6pfUEf5aVjmhCea6buNTMXzYuBplHMU86HuFKkimf1lNCq9yQdgXLx+zpo27ue WRk7CmXmcxExayuBj/MLwXSztWFz37wHyVxg1s6TYpUsgDjvdYx+b1Swxhj+lI21p7 Al/h8msq0yXNQ== Date: Thu, 27 Nov 2025 07:05:04 +0200 From: Mike Rapoport To: Usama Arif Cc: Kiryl Shutsemau , Andrew Morton , changyuanl@google.com, graf@amazon.com, leitao@debian.org, thevlad@meta.com, pratyush@kernel.org, dave.hansen@linux.intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@meta.com Subject: Re: [PATCH] mm/memblock: only mark/clear KHO scratch memory when needed Message-ID: References: <20251126072051.546700-1-usamaarif642@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam12 X-Rspam-User: X-Rspamd-Queue-Id: 7D74DC0009 X-Stat-Signature: ztt1158wnmatnnbuqxeauqc1ytgondf1 X-HE-Tag: 1764219913-57387 X-HE-Meta: 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 mgxqkSUq Ut5sjij+QEybtPX/aLDpYlopqil8Yb5TosMhI2Th55Ud9TyVEXE91qTESRVTI6XMACKvpULA90NkHWaFU9LixOIFJpYOZZ+Xi/n1aXSkXX0exrFMWOIzhcpsaoK/O/tq0tzHXAIqufMAf6X1AsZVV36B5C6Jibc/jG893TsI4W628wZgMKxmsiuv0Se/JSHZ18AF1DPFIzNsk21g3/TR3QSRUdXC9Whk3MWDc4riyP/+en/vV1jVtq6zoguhK7r6POY9x 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: On Wed, Nov 26, 2025 at 11:43:21AM +0000, Usama Arif wrote: > > On 26/11/2025 10:40, Kiryl Shutsemau wrote: > > On Wed, Nov 26, 2025 at 07:20:51AM +0000, Usama Arif wrote: > >> @@ -1126,8 +1126,11 @@ int __init_memblock memblock_reserved_mark_noinit(phys_addr_t base, phys_addr_t > >> */ > >> __init int memblock_mark_kho_scratch(phys_addr_t base, phys_addr_t size) > >> { > >> - return memblock_setclr_flag(&memblock.memory, base, size, 1, > >> - MEMBLOCK_KHO_SCRATCH); > >> + if (IS_ENABLED(CONFIG_MEMBLOCK_KHO_SCRATCH) && is_kho_boot()) > > > > It makes me wounder why CONFIG_MEMBLOCK_KHO_SCRATCH exists? It seems to > > be a proxy for CONFIG_KEXEC_HANDOVER which is the only option that > > selects it and does it always. > > > > Can we make s/CONFIG_MEMBLOCK_KHO_SCRATCH/CONFIG_KEXEC_HANDOVER/ and > > remove IS_ENABLED() from this check? Just is_kho_boot() is enough. > > > > > > Thats a very good point! I imagine it might have been for maybe debug purposes? > > Looking at the code, CONFIG_MEMBLOCK_KHO_SCRATCH shouldnt be needed. I guess > this might be a good time to clean it up. If Mike is happy for it to be replaced > with CONFIG_KEXEC_HANDOVER (and removed where needed), happy to send that > for review instead of this. Yeah, let's kill CONFIG_MEMBLOCK_KHO_SCRATCH and use CONFIG_KEXEC_HANDOVER where needed. IS_ENABLED() is not needed in the check because with CONFIG_MEMBLOCK_KHO_SCRATCH=n both mark_kho_scratch() and clear_kho_scratch() are empty stubs, so it's enough to check is_kho_boot(). > Thanks > Usama -- Sincerely yours, Mike.