[PATCH] free initrds boot option

From: Michael Neuling
Date: Wed Dec 06 2006 - 22:43:22 EST


Add retain_initrd option to control freeing of initrd memory after
extraction. By default, free memory as previously.

Signed-off-by: Michael Neuling <mikey@xxxxxxxxxxx>
---
Updated based on comments from akpm.
Added documentation and changed option name to "retain_initrd"
Tested on POWERPC with CPIOs

Documentation/kernel-parameters.txt | 2 ++
init/initramfs.c | 18 ++++++++++++++++--
2 files changed, 18 insertions(+), 2 deletions(-)

Index: linux-2.6-ozlabs/Documentation/kernel-parameters.txt
===================================================================
--- linux-2.6-ozlabs.orig/Documentation/kernel-parameters.txt
+++ linux-2.6-ozlabs/Documentation/kernel-parameters.txt
@@ -1366,6 +1366,8 @@ and is between 256 and 4096 characters.
resume= [SWSUSP]
Specify the partition device for software suspend

+ retain_initrd [RAM] Keep initrd memory after extraction
+
rhash_entries= [KNL,NET]
Set number of hash buckets for route cache

Index: linux-2.6-ozlabs/init/initramfs.c
===================================================================
--- linux-2.6-ozlabs.orig/init/initramfs.c
+++ linux-2.6-ozlabs/init/initramfs.c
@@ -487,6 +487,17 @@ static char * __init unpack_to_rootfs(ch
return message;
}

+static int do_retain_initrd = 0;
+
+static int __init retain_initrd_param(char *str)
+{
+ if (*str)
+ return 0;
+ do_retain_initrd = 1;
+ return 1;
+}
+__setup("retain_initrd", retain_initrd_param);
+
extern char __initramfs_start[], __initramfs_end[];
#ifdef CONFIG_BLK_DEV_INITRD
#include <linux/initrd.h>
@@ -494,10 +505,13 @@ extern char __initramfs_start[], __initr

static void __init free_initrd(void)
{
-#ifdef CONFIG_KEXEC
unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
unsigned long crashk_end = (unsigned long)__va(crashk_res.end);

+ if (do_retain_initrd)
+ goto skip;
+
+#ifdef CONFIG_KEXEC
/*
* If the initrd region is overlapped with crashkernel reserved region,
* free only memory that is not part of crashkernel region.
@@ -515,7 +529,7 @@ static void __init free_initrd(void)
} else
#endif
free_initrd_mem(initrd_start, initrd_end);
-
+skip:
initrd_start = 0;
initrd_end = 0;
}
-
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