kexec: allocate the kexec control page with KEXEC_CONTROL_MEMORY_GFP

Introduce KEXEC_CONTROL_MEMORY_GFP to allow the architecture code
to override the gfp flags of the allocation for the kexec control
page. The loop in kimage_alloc_normal_control_pages allocates pages
with GFP_KERNEL until a page is found that happens to have an
address smaller than the KEXEC_CONTROL_MEMORY_LIMIT. On systems
with a large memory size but a small KEXEC_CONTROL_MEMORY_LIMIT
the loop will keep allocating memory until the oom killer steps in.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index e60a745ac198..e804306ef5e8 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -40,6 +40,10 @@
 #error KEXEC_CONTROL_MEMORY_LIMIT not defined
 #endif
 
+#ifndef KEXEC_CONTROL_MEMORY_GFP
+#define KEXEC_CONTROL_MEMORY_GFP GFP_KERNEL
+#endif
+
 #ifndef KEXEC_CONTROL_PAGE_SIZE
 #error KEXEC_CONTROL_PAGE_SIZE not defined
 #endif