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Fri, 13 Mar 2026 21:57:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773439021; bh=BwGIzF3Y1kGJ7LSzEz+7QIlkvRAEX1ybLPLbwYlypHg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=D8LFC/Y2BvExaUUaQwCZ1enN784C4eGC3QLIYlLXoQRLLoZbcIPAW+9UHxunos89u W2FcjOgbPlul4rkrHWNMnWcebVKNCNJBcZAC9W9bHqSllID/Yx8/g7Pg0waFNdbV1F PZkKpvhQhygkjCvndRt4AGAp3O3ce5dB8Hf9tYRkl1Yd2G1/EC1V7ihRTEFOlFWtJD TVRWH74L5h1udZNpGw4w/HeSz46hbFXg77yqFlXWTNDJcGX7icfPbrJEmetdc7x+30 MorgajnbJ3XPvDp3w4FMrauooCX4QG0hYbWRVYVLx7aMFlZXvlf6/A/GVpusGs1ME1 T/VOcVRh6Fn9Q== Date: Fri, 13 Mar 2026 16:56:59 -0500 From: "Rob Herring (Arm)" To: Jinjie Ruan Cc: loongarch@lists.linux.dev, cfsworks@gmail.com, alex@ghiti.fr, skhan@linuxfoundation.org, liaoyuanhong@vivo.com, ritesh.list@gmail.com, linux-arm-kernel@lists.infradead.org, kees@kernel.org, leitao@debian.org, lirongqing@baidu.com, corbet@lwn.net, pmladek@suse.com, jbohac@suse.cz, eajames@linux.ibm.com, sourabhjain@linux.ibm.com, palmer@dabbelt.com, vishal.moola@gmail.com, npiggin@gmail.com, dapeng1.mi@linux.intel.com, brgerst@gmail.com, will@kernel.org, paulmck@kernel.org, tglx@kernel.org, rdunlap@infradead.org, hbathini@linux.ibm.com, kexec@lists.infradead.org, bhe@redhat.com, dyoung@redhat.com, x86@kernel.org, pjw@kernel.org, rppt@kernel.org, linux-doc@vger.kernel.org, kernel@xen0n.name, dave.hansen@linux.intel.com, catalin.marinas@arm.com, saravanak@kernel.org, samuel.holland@sifive.com, songshuaishuai@tinylab.org, coxu@redhat.com, fuqiang.wang@easystack.cn, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, osandov@fb.com, chenhuacai@kernel.org, aou@eecs.berkeley.edu, tangyouling@kylinos.cn, hpa@zytor.com, chleroy@kernel.org, linuxppc-dev@lists.ozlabs.org, bp@alien8.de, vgoyal@redhat.com, fvdl@google.com, kevin.brodsky@arm.com, mingo@redhat.com, maddy@linux.ibm.com, akpm@linux-foundation.org, junhui.liu@pigmoral.tech, ardb@kernel.org, mpe@ellerman.id.au, linux-riscv@lists.infradead.org Subject: Re: [PATCH v8 4/5] arm64: kexec: Add support for crashkernel CMA reservation Message-ID: <177343901948.3415566.6726187926870600451.robh@kernel.org> References: <20260302035315.3892241-1-ruanjinjie@huawei.com> <20260302035315.3892241-5-ruanjinjie@huawei.com> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20260302035315.3892241-5-ruanjinjie@huawei.com> On Mon, 02 Mar 2026 11:53:14 +0800, Jinjie Ruan wrote: > Commit 35c18f2933c5 ("Add a new optional ",cma" suffix to the > crashkernel= command line option") and commit ab475510e042 ("kdump: > implement reserve_crashkernel_cma") added CMA support for kdump > crashkernel reservation. > > Crash kernel memory reservation wastes production resources if too > large, risks kdump failure if too small, and faces allocation difficulties > on fragmented systems due to contiguous block constraints. The new > CMA-based crashkernel reservation scheme splits the "large fixed > reservation" into a "small fixed region + large CMA dynamic region": the > CMA memory is available to userspace during normal operation to avoid > waste, and is reclaimed for kdump upon crash—saving memory while > improving reliability. > > So extend crashkernel CMA reservation support to arm64. The following > changes are made to enable CMA reservation: > > - Parse and obtain the CMA reservation size along with other crashkernel > parameters. > - Call reserve_crashkernel_cma() to allocate the CMA region for kdump. > - Include the CMA-reserved ranges for kdump kernel to use. > - Exclude the CMA-reserved ranges from the crash kernel memory to > prevent them from being exported through /proc/vmcore, which is already > done in the crash core. > > Update kernel-parameters.txt to document CMA support for crashkernel on > arm64 architecture. > > Acked-by: Mike Rapoport (Microsoft) > Acked-by: Ard Biesheuvel > Signed-off-by: Jinjie Ruan > --- > v7: > - Correct the inclusion of CMA-reserved ranges for kdump > kernel in of/kexec. > v3: > - Add Acked-by. > v2: > - Free cmem in prepare_elf_headers() > - Add the mtivation. > --- > Documentation/admin-guide/kernel-parameters.txt | 2 +- > arch/arm64/kernel/machine_kexec_file.c | 2 +- > arch/arm64/mm/init.c | 5 +++-- > drivers/of/fdt.c | 9 +++++---- > drivers/of/kexec.c | 9 +++++++++ > 5 files changed, 19 insertions(+), 8 deletions(-) > Acked-by: Rob Herring (Arm)