kernel/0001-kdump-round-up-the-total-memory-size-to-128M-for-cra.patch
Justin M. Forbes f7a3bf6547 kernel-5.9.0-0.rc0.20200813gitdc06fe51d26e.1
* Thu Aug 13 2020 Fedora Kernel Team <kernel-team@fedoraproject.org> [5.9.0-0.rc0.20200813gitdc06fe51d26e.1]
- dc06fe51d26e rebase
- More mismatches ("Justin M. Forbes")
- Fedora config change due to deps ("Justin M. Forbes")
- CONFIG_SND_SOC_MAX98390 is now selected by SND_SOC_INTEL_DA7219_MAX98357A_GENERIC ("Justin M. Forbes")
- Config change required for build part 2 ("Justin M. Forbes")
- Config change required for build ("Justin M. Forbes")
- Fedora config update ("Justin M. Forbes")
- Revert "Merge branch 'make_configs_fix' into 'os-build'" (Justin Forbes)
- redhat/configs/process_configs.sh: Remove *.config.orig files (Prarit Bhargava)
- redhat/configs/process_configs.sh: Add process_configs_known_broken flag (Prarit Bhargava)
- redhat/Makefile: Fix '*-configs' targets (Prarit Bhargava)
- Updated changelog for the release based on v5.8 (Fedora Kernel Team)
- Add ability to sync upstream through Makefile (Don Zickus)
- Add master merge check (Don Zickus)
- Replace hardcoded values 'os-build' and project id with variables (Don Zickus)
- gitattributes: Remove unnecesary export restrictions (Prarit Bhargava)
- redhat/Makefile.common: Fix MARKER (Prarit Bhargava)
Resolves: rhbz#

Signed-off-by: Justin M. Forbes <jforbes@fedoraproject.org>
2020-08-13 12:44:32 -05:00

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Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Dave Young <dyoung@redhat.com>
Date: Mon, 4 Jun 2018 01:38:25 -0400
Subject: [PATCH] kdump: round up the total memory size to 128M for crashkernel
reservation
Message-id: <20180604013831.523644967@redhat.com>
Patchwork-id: 8165
O-Subject: [kernel team] [PATCH RHEL8.0 V2 1/2] kdump: round up the total memory size to 128M for crashkernel reservation
Bugzilla: 1507353
RH-Acked-by: Don Zickus <dzickus@redhat.com>
RH-Acked-by: Baoquan He <bhe@redhat.com>
RH-Acked-by: Pingfan Liu <piliu@redhat.com>
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1507353
Build: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=16534135
Tested: ppc64le, x86_64 with several memory sizes.
The total memory size we get in kernel is usually slightly less than 2G with
2G memory module machine. The main reason is bios/firmware reserve some area
it will not export all memory as usable to Linux.
2G memory X86 kvm guest test result of the total_mem value:
UEFI boot with ovmf: 0x7ef10000
Legacy boot kvm guest: 0x7ff7cc00
This is also a problem on arm64 UEFI booted system according to my test.
Thus for example crashkernel=1G-2G:128M, if we have a 1G memory
machine, we get total size 1023M from firmware then it will not fall
into 1G-2G thus no memory reserved. User will never know that, it is
hard to let user to know the exact total value we get in kernel
An option is to use dmi/smbios to get physical memory size, but it's not
reliable as well. According to Prarit hardware vendors sometimes screw this up.
Thus round up total size to 128M to workaround this problem.
Posted below patch in upstream, but no response yet:
http://lists.infradead.org/pipermail/kexec/2018-April/020568.html
Upstream Status: RHEL only
Signed-off-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Herton R. Krzesinski <herton@redhat.com>
---
kernel/crash_core.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 106e4500fd53..0b3f738178b8 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/sizes.h>
#include <asm/page.h>
#include <asm/sections.h>
@@ -41,6 +42,15 @@ static int __init parse_crashkernel_mem(char *cmdline,
unsigned long long *crash_base)
{
char *cur = cmdline, *tmp;
+ unsigned long long total_mem = system_ram;
+
+ /*
+ * Firmware sometimes reserves some memory regions for it's own use.
+ * so we get less than actual system memory size.
+ * Workaround this by round up the total size to 128M which is
+ * enough for most test cases.
+ */
+ total_mem = roundup(total_mem, SZ_128M);
/* for each entry of the comma-separated list */
do {
@@ -85,13 +95,13 @@ static int __init parse_crashkernel_mem(char *cmdline,
return -EINVAL;
}
cur = tmp;
- if (size >= system_ram) {
+ if (size >= total_mem) {
pr_warn("crashkernel: invalid size\n");
return -EINVAL;
}
/* match ? */
- if (system_ram >= start && system_ram < end) {
+ if (total_mem >= start && total_mem < end) {
*crash_size = size;
break;
}
--
2.26.2