[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/kernel/kexec.c b/kernel/kexec.c
index 2c95848..1197de8 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -26,6 +26,9 @@
#include <asm/system.h>
#include <asm/semaphore.h>
+/* Per cpu memory for storing cpu states in case of system crash. */
+note_buf_t* crash_notes;
+
/* Location of the reserved area for the crash kernel */
struct resource crashk_res = {
.name = "Crash kernel",
@@ -1060,3 +1063,16 @@
xchg(&kexec_lock, 0);
}
}
+
+static int __init crash_notes_memory_init(void)
+{
+ /* Allocate memory for saving cpu registers. */
+ crash_notes = alloc_percpu(note_buf_t);
+ if (!crash_notes) {
+ printk("Kexec: Memory allocation for saving cpu register"
+ " states failed\n");
+ return -ENOMEM;
+ }
+ return 0;
+}
+module_init(crash_notes_memory_init)