[PATCH] kdump: dynamic per cpu allocation of memory for saving cpu registers
- In case of system crash, current state of cpu registers is saved in memory
in elf note format. So far memory for storing elf notes was being allocated
statically for NR_CPUS.
- This patch introduces dynamic allocation of memory for storing elf notes.
It uses alloc_percpu() interface. This should lead to better memory usage.
- Introduced based on Andi Kleen's and Eric W. Biederman's suggestions.
- This patch also moves memory allocation for elf notes from architecture
dependent portion to architecture independent portion. Now crash_notes is
architecture independent. The whole idea is that size of memory to be
allocated per cpu (MAX_NOTE_BYTES) can be architecture dependent and
allocation of this memory can be architecture independent.
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/kernel/crash.c b/arch/i386/kernel/crash.c
index 10fe656..f1e65c2 100644
--- a/arch/i386/kernel/crash.c
+++ b/arch/i386/kernel/crash.c
@@ -25,7 +25,6 @@
#include <mach_ipi.h>
-note_buf_t crash_notes[NR_CPUS];
/* This keeps a track of which one is crashing cpu. */
static int crashing_cpu;
@@ -72,7 +71,9 @@
* squirrelled away. ELF notes happen to provide
* all of that that no need to invent something new.
*/
- buf = &crash_notes[cpu][0];
+ buf = (u32*)per_cpu_ptr(crash_notes, cpu);
+ if (!buf)
+ return;
memset(&prstatus, 0, sizeof(prstatus));
prstatus.pr_pid = current->pid;
elf_core_copy_regs(&prstatus.pr_reg, regs);
diff --git a/arch/ppc/kernel/machine_kexec.c b/arch/ppc/kernel/machine_kexec.c
index a882b0d..84d65a8 100644
--- a/arch/ppc/kernel/machine_kexec.c
+++ b/arch/ppc/kernel/machine_kexec.c
@@ -28,12 +28,6 @@
const extern unsigned char relocate_new_kernel[];
const extern unsigned int relocate_new_kernel_size;
-/*
- * Provide a dummy crash_notes definition while crash dump arrives to ppc.
- * This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
- */
-note_buf_t crash_notes[NR_CPUS];
-
void machine_shutdown(void)
{
if (ppc_md.machine_shutdown)
diff --git a/arch/s390/kernel/crash.c b/arch/s390/kernel/crash.c
index 7bd169c..926ccee 100644
--- a/arch/s390/kernel/crash.c
+++ b/arch/s390/kernel/crash.c
@@ -10,8 +10,6 @@
#include <linux/threads.h>
#include <linux/kexec.h>
-note_buf_t crash_notes[NR_CPUS];
-
void machine_crash_shutdown(struct pt_regs *regs)
{
}
diff --git a/arch/x86_64/kernel/crash.c b/arch/x86_64/kernel/crash.c
index 535e044..efe4507 100644
--- a/arch/x86_64/kernel/crash.c
+++ b/arch/x86_64/kernel/crash.c
@@ -19,8 +19,6 @@
#include <asm/nmi.h>
#include <asm/hw_irq.h>
-note_buf_t crash_notes[NR_CPUS];
-
void machine_crash_shutdown(struct pt_regs *regs)
{
/* This function is only called after the system