[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>

5 files changed, 2 insertions, 12 deletions

diff --git a/include/asm-i386/kexec.h b/include/asm-i386/kexec.h
index 6ed2a03e37b34..d80d446498fbc 100644
--- a/include/asm-i386/kexec.h
+++ b/include/asm-i386/kexec.h
@@ -26,8 +26,5 @@
 #define KEXEC_ARCH KEXEC_ARCH_386
 
 #define MAX_NOTE_BYTES 1024
-typedef u32 note_buf_t[MAX_NOTE_BYTES/4];
-
-extern note_buf_t crash_notes[];
 
 #endif /* _I386_KEXEC_H */
diff --git a/include/asm-powerpc/kexec.h b/include/asm-powerpc/kexec.h
index 4263af3cadfde..e363752276ef3 100644
--- a/include/asm-powerpc/kexec.h
+++ b/include/asm-powerpc/kexec.h
@@ -38,9 +38,6 @@
 #ifdef CONFIG_KEXEC
 
 #define MAX_NOTE_BYTES 1024
-typedef u32 note_buf_t[MAX_NOTE_BYTES / sizeof(u32)];
-
-extern note_buf_t crash_notes[];
 
 #ifdef __powerpc64__
 extern void kexec_smp_wait(void);	/* get and clear naca physid, wait for
diff --git a/include/asm-s390/kexec.h b/include/asm-s390/kexec.h
index 54cf7d9f251c6..b4809d98fe691 100644
--- a/include/asm-s390/kexec.h
+++ b/include/asm-s390/kexec.h
@@ -35,8 +35,5 @@
 #define KEXEC_ARCH KEXEC_ARCH_S390
 
 #define MAX_NOTE_BYTES 1024
-typedef u32 note_buf_t[MAX_NOTE_BYTES/4];
-
-extern note_buf_t crash_notes[];
 
 #endif /*_S390_KEXEC_H */
diff --git a/include/asm-x86_64/kexec.h b/include/asm-x86_64/kexec.h
index 42d2ff15c592d..cea78543a574e 100644
--- a/include/asm-x86_64/kexec.h
+++ b/include/asm-x86_64/kexec.h
@@ -26,8 +26,5 @@
 #define KEXEC_ARCH KEXEC_ARCH_X86_64
 
 #define MAX_NOTE_BYTES 1024
-typedef u32 note_buf_t[MAX_NOTE_BYTES/4];
-
-extern note_buf_t crash_notes[];
 
 #endif /* _X86_64_KEXEC_H */
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index c8468472aec09..c1cd9b31159e8 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -125,6 +125,8 @@ extern struct kimage *kexec_image;
 /* Location of a reserved region to hold the crash kernel.
  */
 extern struct resource crashk_res;
+typedef u32 note_buf_t[MAX_NOTE_BYTES/4];
+extern note_buf_t *crash_notes;
 
 #else /* !CONFIG_KEXEC */
 struct pt_regs;