[PATCH] tune vmalloc size

There are a few devices that use lots of ioremap space.  vmalloc space is a
showstopper problem for them.

this patch adds the vmalloc=<size> boot parameter to override
__VMALLOC_RESERVE.  The default is 128mb right now - e.g.  vmalloc=256m
doubles the size.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjanv@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/kernel-parameters.txt

@@ -453,6 +453,11 @@ running once the system is up.
 	hd?=		[HW] (E)IDE subsystem
 	hd?lun=		See Documentation/ide.txt.
 
+	highmem=nn[KMG]	[KNL,BOOT] forces the highmem zone to have an exact
+			size of <nn>. This works even on boxes that have no
+			highmem otherwise. This also works to reduce highmem
+			size on bigger boxes.
+
 	hisax=		[HW,ISDN]
 			See Documentation/isdn/README.HiSax.
 
@@ -1293,6 +1298,12 @@ running once the system is up.
 			This is actually a boot loader parameter; the value is
 			passed to the kernel using a special protocol.
 
+	vmalloc=nn[KMG]	[KNL,BOOT] forces the vmalloc area to have an exact
+			size of <nn>. This can be used to increase the
+			minimum size (128MB on x86). It can also be used to
+			decrease the size and leave more room for directly
+			mapped kernel RAM.
+
 	vmhalt=		[KNL,S390]
 
 	vmpoff=		[KNL,S390] 

arch/i386/boot/setup.S

@@ -156,7 +156,7 @@ cmd_line_ptr:	.long 0			# (Header version 0x0202 or later)
 					# can be located anywhere in
 					# low memory 0x10000 or higher.
 
-ramdisk_max:	.long (MAXMEM-1) & 0x7fffffff
+ramdisk_max:	.long (-__PAGE_OFFSET-(512 << 20)-1) & 0x7fffffff
 					# (Header version 0x0203 or later)
 					# The highest safe address for
 					# the contents of an initrd

arch/i386/kernel/setup.c

@@ -815,6 +815,14 @@ static void __init parse_cmdline_early (char ** cmdline_p)
 		if (c == ' ' && !memcmp(from, "highmem=", 8))
 			highmem_pages = memparse(from+8, &from) >> PAGE_SHIFT;
 	
+		/*
+		 * vmalloc=size forces the vmalloc area to be exactly 'size'
+		 * bytes. This can be used to increase (or decrease) the
+		 * vmalloc area - the default is 128m.
+		 */
+		if (c == ' ' && !memcmp(from, "vmalloc=", 8))
+			__VMALLOC_RESERVE = memparse(from+8, &from);
+
 		c = *(from++);
 		if (!c)
 			break;

arch/i386/mm/init.c

@@ -40,6 +40,8 @@
 #include <asm/tlbflush.h>
 #include <asm/sections.h>
 
+unsigned int __VMALLOC_RESERVE = 128 << 20;
+
 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
 unsigned long highstart_pfn, highend_pfn;
 

include/asm-i386/page.h

@@ -94,13 +94,13 @@ typedef struct { unsigned long pgprot; } pgprot_t;
  * and CONFIG_HIGHMEM64G options in the kernel configuration.
  */
 
+#ifndef __ASSEMBLY__
+
 /*
  * This much address space is reserved for vmalloc() and iomap()
  * as well as fixmap mappings.
  */
-#define __VMALLOC_RESERVE	(128 << 20)
-
-#ifndef __ASSEMBLY__
+extern unsigned int __VMALLOC_RESERVE;
 
 /* Pure 2^n version of get_order */
 static __inline__ int get_order(unsigned long size)

mm/vmalloc.c

@@ -247,6 +247,8 @@ struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
 out:
 	write_unlock(&vmlist_lock);
 	kfree(area);
+	if (printk_ratelimit())
+		printk(KERN_WARNING "allocation failed: out of vmalloc space - use vmalloc=<size> to increase size.\n");
 	return NULL;
 }