proc_pid_statm

William Lee Irwin III
2001-12-06T21:42:23Z

It's unclear where the number 0x60000000 comes from. I believe it's
attempting to anticipate the layout of the process address space, in
particular the fact that ELF interpreters are mapped starting at
ELF_ET_DYN_BASE when formatted as dynamic shared objects, (and this
used to happen around 0x60000000 if I remember old ldd output), and in
many cases, all dynamic shared objects are mapped at still higher
addresses. Open-coding this number seems non-portable.

Could someone comment on this?

Cheers,
Bill

I think the author may have had this in mind (though this may still
report inaccurately on a few architectures):

--- linux-2.4.17-pre4-virgin/fs/proc/array.c Thu Oct 11 09:00:01 2001
+++ linux-2.4.17-pre4/fs/proc/array.c Thu Dec 6 13:36:33 2001
@@ -75,6 +75,7 @@
#include <asm/pgtable.h>
#include <asm/io.h>
#include <asm/processor.h>
+#include <linux/elf.h>

/* Gcc optimizes away "strlen(x)" for constant x */
#define ADDBUF(buffer, string) \
@@ -491,14 +492,13 @@
share += shared;
dt += dirty;
size += total;
- if (vma->vm_flags & VM_EXECUTABLE)
- trs += pages; /* text */
- else if (vma->vm_flags & VM_GROWSDOWN)
- drs += pages; /* stack */
- else if (vma->vm_end > 0x60000000)
- lrs += pages; /* library */
- else
- drs += pages;
+ if (vma->vm_flags & VM_EXECUTABLE) {
+ if(vma->vm_end > ELF_ET_DYN_BASE)
+ lrs += pages; /* library */
+ else
+ trs += pages; /* text */
+ } else
+ drs += pages; /* stack and data */
vma = vma->vm_next;
}
up_read(&mm->mmap_sem);