On Wednesday 10 May 2017 08:28 PM, Michal Suchánek wrote:
On Wed, 3 May 2017 12:43:33 +0530
Hari Bathini <hbathini@xxxxxxxxxxxxxxxxxx> wrote:
On Tuesday 02 May 2017 09:26 PM, Michal Suchanek wrote:
With fadump (dump capture) kernel booting like a regular kernel, it
almost needs the same amount of memory to boot as the production
kernel, which is unwarranted for a dump capture kernel. But with no
option to disable some of the unnecessary subsystems in fadump
kernel, that much memory is wasted on fadump, depriving the
production kernel of that memory.
Introduce kernel parameter 'fadump_append=' that would take regular
kernel parameters to be appended when fadump is active.
This 'fadump_append=' parameter can be leveraged to pass parameters
like nr_cpus=1, cgroup_disable=memory and numa=off, to disable
unwarranted resources/subsystems.
Also, ensure the log "Firmware-assisted dump is active" is printed
early in the boot process to put the subsequent fadump messages in
context.
Suggested-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Hari Bathini <hbathini@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Michal Suchanek <msuchanek@xxxxxxx>
---
v4:
- use space separated arguments instead of comma separated
- do not append parameters when fadummp is disabled
---
arch/powerpc/kernel/fadump.c | 27 ++++++++++++++++++++++++---
1 file changed, 24 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/kernel/fadump.c
b/arch/powerpc/kernel/fadump.c index ebf2e9c..e0c728a 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -79,8 +79,10 @@ int __init early_init_dt_scan_fw_dump(unsigned
long node,
* dump data waiting for us.
*/
fdm_active = of_get_flat_dt_prop(node, "ibm,kernel-dump",
NULL);
- if (fdm_active)
+ if (fdm_active) {
+ pr_info("Firmware-assisted dump is active.\n");
fw_dump.dump_active = 1;
+ }
/* Get the sizes required to store dump data for the
firmware provided
* dump sections.
@@ -263,8 +265,12 @@ int __init fadump_reserve_mem(void)
{
unsigned long base, size, memory_boundary;
- if (!fw_dump.fadump_enabled)
+ if (!fw_dump.fadump_enabled) {
+ if (fw_dump.dump_active)
+ pr_warn("Firmware-assisted dump was active
but kernel"
+ " booted with fadump disabled!\n");
return 0;
+ }
if (!fw_dump.fadump_supported) {
printk(KERN_INFO "Firmware-assisted dump is not
supported on" @@ -304,7 +310,6 @@ int __init
fadump_reserve_mem(void) memory_boundary = memblock_end_of_DRAM();
if (fw_dump.dump_active) {
- printk(KERN_INFO "Firmware-assisted dump is
active.\n"); /*
* If last boot has crashed then reserve all the
memory
* above boot_memory_size so that we don't touch
it until @@ -363,6 +368,22 @@ unsigned long __init
arch_reserved_kernel_pages(void) return memblock_reserved_size() /
PAGE_SIZE; }
+/* Look for fadump_append= cmdline option. */
+static int __init early_fadump_append_param(char *p)
+{
+ if (!p)
+ return 1;
+
+ if (fw_dump.fadump_enabled && fw_dump.dump_active) {
+ pr_info("enforcing additional parameters (%s) passed
through "
+ "'fadump_append=' parameter\n", p);
+ parse_early_options(p);
While testing this on a system with yaboot bootloader, it seems that
parsing a parameter with syntax like fadump_append="nr_cpus=1
numa=off" is not resulting in the intended way..
Since yaboot arguments are quoted you will probably want something like
append = "quiet splash somearg1 somearg2 fadump_append=\"nr_cpus=1
numa=off\""
I did try this out. But it wasn't helping either..
in yaboot.conf
Looking at the yaboot parser it seems to handle quoting of quotes so
unlike your parser that does not handle quoting of commas it allows
passing arbitrary arguments to both the normal kernel and the fadump
kernel.
Will improve on v5 to ensure quotes are taken care of..
Thanks
Hari
--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
