From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from aserp2130.oracle.com ([141.146.126.79]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1lEN4D-0003rV-Ql for kexec@lists.infradead.org; Tue, 23 Feb 2021 02:04:50 +0000 Subject: Re: [PATCH v3 1/1] kernel/crash_core: Add crashkernel=auto for vmcore creation References: <20210211180814.69708-1-saeed.mirzamohammadi@oracle.com> <20210218020203.GC2871@MiWiFi-R3L-srv> From: john.p.donnelly@oracle.com Message-ID: Date: Mon, 22 Feb 2021 20:03:13 -0600 In-Reply-To: <20210218020203.GC2871@MiWiFi-R3L-srv> Content-Language: en-US MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Baoquan He , Saeed Mirzamohammadi Cc: linux-doc@vger.kernel.org, "Peter Zijlstra (Intel)" , Christian Brauner , Ingo Molnar , Jonathan Corbet , Mauro Carvalho Chehab , Masahiro Yamada , Sami Tolvanen , Dave Young , Vivek Goyal , John Donnelly , Kees Cook , "Paul E. McKenney" , Andrey Konovalov , Frederic Weisbecker , "Guilherme G. Piccoli" , "Steven Rostedt (VMware)" , Josh Poimboeuf , Thomas Gleixner , Stephen Boyd , Randy Dunlap , kexec@lists.infradead.org, linux-kernel@vger.kernel.org, YiFei Zhu , Andrew Morton , Mike Rapoport , Mike Kravetz On 2/17/21 8:02 PM, Baoquan He wrote: > On 02/11/21 at 10:08am, Saeed Mirzamohammadi wrote: >> This adds crashkernel=auto feature to configure reserved memory for >> vmcore creation. CONFIG_CRASH_AUTO_STR is defined to be set for >> different kernel distributions and different archs based on their >> needs. >> >> Signed-off-by: Saeed Mirzamohammadi >> Signed-off-by: John Donnelly >> Tested-by: John Donnelly >> --- >> Documentation/admin-guide/kdump/kdump.rst | 3 ++- >> .../admin-guide/kernel-parameters.txt | 6 +++++ >> arch/Kconfig | 24 +++++++++++++++++++ >> kernel/crash_core.c | 7 ++++++ >> 4 files changed, 39 insertions(+), 1 deletion(-) >> >> diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst >> index 2da65fef2a1c..e55cdc404c6b 100644 >> --- a/Documentation/admin-guide/kdump/kdump.rst >> +++ b/Documentation/admin-guide/kdump/kdump.rst >> @@ -285,7 +285,8 @@ This would mean: >> 2) if the RAM size is between 512M and 2G (exclusive), then reserve 64M >> 3) if the RAM size is larger than 2G, then reserve 128M >> >> - >> +Or you can use crashkernel=auto to choose the crash kernel memory size >> +based on the recommended configuration set for each arch. >> >> Boot into System Kernel >> ======================= >> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt >> index 7d4e523646c3..aa2099465458 100644 >> --- a/Documentation/admin-guide/kernel-parameters.txt >> +++ b/Documentation/admin-guide/kernel-parameters.txt >> @@ -736,6 +736,12 @@ >> a memory unit (amount[KMG]). See also >> Documentation/admin-guide/kdump/kdump.rst for an example. >> >> + crashkernel=auto >> + [KNL] This parameter will set the reserved memory for >> + the crash kernel based on the value of the CRASH_AUTO_STR >> + that is the best effort estimation for each arch. See also >> + arch/Kconfig for further details. >> + >> crashkernel=size[KMG],high >> [KNL, X86-64] range could be above 4G. Allow kernel >> to allocate physical memory region from top, so could >> diff --git a/arch/Kconfig b/arch/Kconfig >> index af14a567b493..f87c88ffa2f8 100644 >> --- a/arch/Kconfig >> +++ b/arch/Kconfig >> @@ -14,6 +14,30 @@ menu "General architecture-dependent options" >> config CRASH_CORE >> bool >> >> +if CRASH_CORE >> + >> +config CRASH_AUTO_STR >> + string "Memory reserved for crash kernel" >> + depends on CRASH_CORE >> + default "1G-64G:128M,64G-1T:256M,1T-:512M" >> + help >> + This configures the reserved memory dependent >> + on the value of System RAM. The syntax is: >> + crashkernel=:[,:,...][@offset] >> + range=start-[end] >> + >> + For example: >> + crashkernel=512M-2G:64M,2G-:128M >> + >> + This would mean: >> + >> + 1) if the RAM is smaller than 512M, then don't reserve anything >> + (this is the "rescue" case) >> + 2) if the RAM size is between 512M and 2G (exclusive), then reserve 64M >> + 3) if the RAM size is larger than 2G, then reserve 128M >> + >> +endif # CRASH_CORE > > Wondering if this CRASH_CORE ifdeffery is a little redundent here > since CRASH_CORE dependency has been added. Except of this, I like this > patch. As we discussed in private threads, we can try to push it into > mainline and continue improving later. Hi, Are we good to move forward with this and apply it now? Dave Young acked it. Thank you, John. (Note - I am currently not on any vger.kernel.org dlist at the moment so please cc me ). > > >> + >> config KEXEC_CORE >> select CRASH_CORE >> bool >> diff --git a/kernel/crash_core.c b/kernel/crash_core.c >> index 106e4500fd53..ab0a2b4b1ffa 100644 >> --- a/kernel/crash_core.c >> +++ b/kernel/crash_core.c >> @@ -7,6 +7,7 @@ >> #include >> #include >> #include >> +#include >> >> #include >> #include >> @@ -250,6 +251,12 @@ static int __init __parse_crashkernel(char *cmdline, >> if (suffix) >> return parse_crashkernel_suffix(ck_cmdline, crash_size, >> suffix); >> +#ifdef CONFIG_CRASH_AUTO_STR >> + if (strncmp(ck_cmdline, "auto", 4) == 0) { >> + ck_cmdline = CONFIG_CRASH_AUTO_STR; >> + pr_info("Using crashkernel=auto, the size chosen is a best effort estimation.\n"); >> + } >> +#endif >> /* >> * if the commandline contains a ':', then that's the extended >> * syntax -- if not, it must be the classic syntax >> -- >> 2.27.0 >> > _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec