On 02/23/21 at 08:01pm, Kairui Song wrote:

On Thu, Feb 18, 2021 at 10:03 AM Baoquan He [off-list ref] wrote:

quoted

On 02/11/21 at 10:08am, Saeed Mirzamohammadi wrote:

...

quoted

quoted

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=<range1>:<size1>[,<range2>:<size2>,...][@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.

I believe "if CRASH_CORE" is not needed as it already "depends on
CRASH_CORE", tested with CRASH_CORE=y or 'not set', it just works.

Thanks for testing and confirmation, Kairui.

Saeed, can you post a v4 with CRASH_CORE ifdeffery removed? Maybe this
week?

Thanks
Baoquan

quoted

quoted

+
 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 <linux/crash_core.h>
 #include <linux/utsname.h>
 #include <linux/vmalloc.h>
+#include <linux/kexec.h>

 #include <asm/page.h>
 #include <asm/sections.h>

@@ -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

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-- 
Best Regards,
Kairui Song