From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx0b-00069f02.pphosted.com ([205.220.177.32]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mnlYY-008UIW-9I for kexec@lists.infradead.org; Thu, 18 Nov 2021 17:50:44 +0000 From: Eric DeVolder Subject: [RFC v1 2/8] crash hp: Introduce CRASH_HOTPLUG configuration options Date: Thu, 18 Nov 2021 12:49:42 -0500 Message-Id: <20211118174948.37435-3-eric.devolder@oracle.com> In-Reply-To: <20211118174948.37435-1-eric.devolder@oracle.com> References: <20211118174948.37435-1-eric.devolder@oracle.com> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: linux-kernel@vger.kernel.org, x86@kernel.org, kexec@lists.infradead.org, ebiederm@xmission.com, dyoung@redhat.com, bhe@redhat.com, vgoyal@redhat.com Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, nramas@linux.microsoft.com, thomas.lendacky@amd.com, robh@kernel.org, efault@gmx.de, rppt@kernel.org, konrad.wilk@oracle.com, boris.ostrovsky@oracle.com, eric.devolder@oracle.com The bulk of the support for CPU and memory hotplug support for crash is controlled by the CRASH_HOTPLUG configuration option, introduced by this patch. The CRASH_HOTPLUG_ELFCOREHDR_SZ related configuration option is also introduced with this patch. Signed-off-by: Eric DeVolder --- arch/x86/Kconfig | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 95dd1ee01546..5feb829adb60 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2046,6 +2046,32 @@ config CRASH_DUMP (CONFIG_RELOCATABLE=y). For more details see Documentation/admin-guide/kdump/kdump.rst +config CRASH_HOTPLUG + bool "kernel updates of crash elfcorehdr" + depends on CRASH_DUMP && (HOTPLUG_CPU || MEMORY_HOTPLUG) && KEXEC_FILE + help + Enable the kernel to update the crash elfcorehdr (which contains + the list of CPUs and memory regions) directly when hot plug/unplug + of CPUs or memory. Otherwise userspace must monitor these hot + plug/unplug change notifications via udev in order to + unload-then-reload the crash kernel so that the list of CPUs and + memory regions is kept up-to-date. Note that the udev CPU and + memory change notifications still occur (however, userspace is not + required to monitor for crash dump purposes). + +config CRASH_HOTPLUG_ELFCOREHDR_SZ + depends on CRASH_HOTPLUG + int + default 131072 + help + Specify the maximum size of the elfcorehdr buffer/segment. + The 128KiB default is sized so that it can accommodate 2048 + Elf64_Phdr, where each Phdr represents either a CPU or a + region of memory. + For example, this size can accommodate hotplugging a machine + with up to 1024 CPUs and up to 1024 memory regions (e.g. 1TiB + with 1024 1GiB memory DIMMs). + config KEXEC_JUMP bool "kexec jump" depends on KEXEC && HIBERNATION -- 2.27.0 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec