[PATCH] Add retain_initrd boot option

Add retain_initrd option to control freeing of initrd memory after extraction. By default, free memory as previously. The first boot will need to hold a copy of the in memory fs for the second boot. This image can be large (much larger than the kernel), hence we can save time when the memory loader is slow. Also, it reduces the memory footprint while extracting the first boot since you don't need another copy of the fs. Signed-off-by: Michael Neuling <mikey@neuling.org> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

[PATCH] Add retain_initrd boot option
Add retain_initrd option to control freeing of initrd memory after extraction. By default, free memory as previously. The first boot will need to hold a copy of the in memory fs for the second boot. This image can be large (much larger than the kernel), hence we can save time when the memory loader is slow. Also, it reduces the memory footprint while extracting the first boot since you don't need another copy of the fs. Signed-off-by: Michael Neuling <mikey@neuling.org> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Michael Neuling · Linus Torvalds
1 parent 70e840499a
Showing 2 changed files with 18 additions and 1 deletions Side-by-side Diff
Documentation/kernel-parameters.txt
init/initramfs.c
@@ -1396,6 +1396,8 @@
 			in <PAGE_SIZE> units (needed only for swap files).
 			See  Documentation/power/swsusp-and-swap-files.txt
  
+	retain_initrd	[RAM] Keep initrd memory after extraction
+
 	rhash_entries=	[KNL,NET]
 			Set number of hash buckets for route cache
  
@@ -491,6 +491,17 @@
 	return message;
 }
  
+static int __initdata do_retain_initrd;
+
+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>
  
@@ -501,7 +512,11 @@
 #ifdef CONFIG_KEXEC
 	unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
 	unsigned long crashk_end   = (unsigned long)__va(crashk_res.end);
+#endif
+	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.
@@ -519,7 +534,7 @@
 	} else
 #endif
 		free_initrd_mem(initrd_start, initrd_end);
-
+skip:
 	initrd_start = 0;
 	initrd_end = 0;
 }
...	...	@@ -1396,6 +1396,8 @@
1396	1396	in <PAGE_SIZE> units (needed only for swap files).
1397	1397	See Documentation/power/swsusp-and-swap-files.txt
1398	1398
	1399	+ retain_initrd [RAM] Keep initrd memory after extraction
	1400	+
1399	1401	rhash_entries= [KNL,NET]
1400	1402	Set number of hash buckets for route cache
1401	1403
...	...	@@ -491,6 +491,17 @@
491	491	return message;
492	492	}
493	493
	494	+static int __initdata do_retain_initrd;
	495	+
	496	+static int __init retain_initrd_param(char *str)
	497	+{
	498	+ if (*str)
	499	+ return 0;
	500	+ do_retain_initrd = 1;
	501	+ return 1;
	502	+}
	503	+__setup("retain_initrd", retain_initrd_param);
	504	+
494	505	extern char __initramfs_start[], __initramfs_end[];
495	506	#ifdef CONFIG_BLK_DEV_INITRD
496	507	#include <linux/initrd.h>
497	508
...	...	@@ -501,7 +512,11 @@
501	512	#ifdef CONFIG_KEXEC
502	513	unsigned long crashk_start = (unsigned long)__va(crashk_res.start);
503	514	unsigned long crashk_end = (unsigned long)__va(crashk_res.end);
	515	+#endif
	516	+ if (do_retain_initrd)
	517	+ goto skip;
504	518
	519	+#ifdef CONFIG_KEXEC
505	520	/*
506	521	* If the initrd region is overlapped with crashkernel reserved region,
507	522	* free only memory that is not part of crashkernel region.
...	...	@@ -519,7 +534,7 @@
519	534	} else
520	535	#endif
521	536	free_initrd_mem(initrd_start, initrd_end);
522		-
	537	+skip:
523	538	initrd_start = 0;
524	539	initrd_end = 0;
525	540	}