diff -purN -X /home/mbligh/.diff.exclude 390-slabtune/arch/i386/Kconfig 410-topdown/arch/i386/Kconfig
--- 390-slabtune/arch/i386/Kconfig 2004-02-28 11:19:31.000000000 -0800
+++ 410-topdown/arch/i386/Kconfig 2004-02-28 11:20:41.000000000 -0800
@@ -1587,6 +1587,15 @@ config KGDB_SYSRQ
to interrupt the system before the serial port control C is
available. Just say yes here.
+config MMAP_TOPDOWN
+ bool "Top-down vma allocation"
+ help
+ Say Y here to have the kernel change its vma allocation policy
+ to allocate vma's from the top of the address space down, and
+ to shove the stack low so as to conserve virtualspace. This is
+ risky because various apps, including a number of versions of
+ ld.so, depend on the kernel's bottom-up behavior.
+
config FRAME_POINTER
bool "Compile the kernel with frame pointers"
default KGDB
diff -purN -X /home/mbligh/.diff.exclude 390-slabtune/arch/i386/mm/pgtable.c 410-topdown/arch/i386/mm/pgtable.c
--- 390-slabtune/arch/i386/mm/pgtable.c 2004-02-28 09:54:25.000000000 -0800
+++ 410-topdown/arch/i386/mm/pgtable.c 2004-02-28 11:20:41.000000000 -0800
@@ -320,3 +320,59 @@ out_free:
kmem_cache_free(pgd_cache, pgd);
}
+#define GLIBC_BUFFER (32*1024*1024)
+
+/*
+ * This is total crap; it needs to use the free area cache to mitigate
+ * catastrophic O(n) search with many vmas.
+ */
+unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
+ unsigned long len, unsigned long pgoff,
+ unsigned long flags)
+{
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma, *prev;
+
+ len = PAGE_ALIGN(len);
+ addr = PAGE_ALIGN(addr);
+
+ if (len > TASK_SIZE)
+ return -ENOMEM;
+
+ if (addr) {
+ struct vm_area_struct *vma;
+ vma = find_vma(mm, addr);
+ if (TASK_SIZE - len >= addr &&
+ (!vma || addr + len <= vma->vm_start))
+ goto out;
+ }
+
+ if (!mm->mmap) {
+ if (len > TASK_SIZE - GLIBC_BUFFER)
+ addr = TASK_SIZE - len;
+ else
+ addr = TASK_SIZE - GLIBC_BUFFER - len;
+ goto out;
+ }
+
+ addr = -ENOMEM;
+ for (prev = NULL, vma = mm->mmap; vma; prev = vma, vma = vma->vm_next) {
+ unsigned long lo, hi;
+ lo = prev ? prev->vm_end : 0;
+ hi = vma->vm_start;
+ if (hi - lo >= len && (addr == -ENOMEM || addr < hi - len))
+ addr = hi - len;
+ }
+ /*
+ * We're at the last one; let's try the top, but only if nothing
+ * else can be found (to respect GLIBC_BUFFER).
+ */
+ if (prev && TASK_SIZE - prev->vm_end >= len) {
+ if (TASK_SIZE - GLIBC_BUFFER - prev->vm_end >= len)
+ addr = TASK_SIZE - GLIBC_BUFFER - len;
+ else if (addr == -ENOMEM)
+ addr = TASK_SIZE - len;
+ }
+out:
+ return addr;
+}
diff -purN -X /home/mbligh/.diff.exclude 390-slabtune/fs/binfmt_elf.c 410-topdown/fs/binfmt_elf.c
--- 390-slabtune/fs/binfmt_elf.c 2004-02-28 11:18:38.000000000 -0800
+++ 410-topdown/fs/binfmt_elf.c 2004-02-28 11:20:41.000000000 -0800
@@ -7,6 +7,7 @@
* Tools".
*
* Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
+ * Top-down vma allocation support, William Irwin, IBM, 2003
*/
#include <linux/module.h>
@@ -333,8 +334,13 @@ static unsigned long load_elf_interp(str
if (retval < 0)
goto out_close;
+#ifndef CONFIG_MMAP_TOPDOWN
eppnt = elf_phdata;
for (i=0; i<interp_elf_ex->e_phnum; i++, eppnt++) {
+#else
+ eppnt = &elf_phdata[interp_elf_ex->e_phnum - 1];
+ for (i = interp_elf_ex->e_phnum - 1; i >= 0; --i, --eppnt) {
+#endif
if (eppnt->p_type == PT_LOAD) {
int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
int elf_prot = 0;
@@ -348,7 +354,8 @@ static unsigned long load_elf_interp(str
if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
elf_type |= MAP_FIXED;
- map_addr = elf_map(interpreter, load_addr + vaddr, eppnt, elf_prot, elf_type);
+ map_addr = load_addr_set ? load_addr + vaddr : 0;
+ map_addr = elf_map(interpreter, map_addr, eppnt, elf_prot, elf_type);
error = map_addr;
if (BAD_ADDR(map_addr))
goto out_close;
diff -purN -X /home/mbligh/.diff.exclude 390-slabtune/include/asm-i386/a.out.h 410-topdown/include/asm-i386/a.out.h
--- 390-slabtune/include/asm-i386/a.out.h 2002-12-09 18:45:54.000000000 -0800
+++ 410-topdown/include/asm-i386/a.out.h 2004-02-28 11:20:42.000000000 -0800
@@ -19,7 +19,16 @@ struct exec
#ifdef __KERNEL__
+/*
+ * Typical ELF load address is 0x8048000, which is 128MB + 288KB.
+ * Shoving the stack very close to it lets smaller programs fit in
+ * a single pagetable page's worth of virtualspace.
+ */
+#ifdef CONFIG_MMAP_TOPDOWN
+#define STACK_TOP ((128 << 20) + (256 << 10))
+#else
#define STACK_TOP TASK_SIZE
+#endif
#endif
diff -purN -X /home/mbligh/.diff.exclude 390-slabtune/include/asm-i386/pgtable.h 410-topdown/include/asm-i386/pgtable.h
--- 390-slabtune/include/asm-i386/pgtable.h 2004-02-28 09:54:25.000000000 -0800
+++ 410-topdown/include/asm-i386/pgtable.h 2004-02-28 11:20:42.000000000 -0800
@@ -25,6 +25,10 @@
#include <linux/list.h>
#include <linux/spinlock.h>
+#ifdef CONFIG_MMAP_TOPDOWN
+#define HAVE_ARCH_UNMAPPED_AREA
+#endif
+
/*
* ZERO_PAGE is a global shared page that is always zero: used
* for zero-mapped memory areas etc..