Re: [PATCH 2.6.14-rc2] fix incorrect mm->hiwater_vm and mm->hiwater_rss

[Jay Lan <jlan@engr.sgi.com>]

Christoph Lameter wrote:
> On Wed, 21 Sep 2005, Jay Lan wrote:
> 
> 
>>>5. Please add appropriate CONFIG, dummy macros etc., so that no time
>>>   is wasted on these updates in all the vanilla systems which have no
>>>   interest in them - but maybe Christoph already has that well in hand.
>>
>>It is used in enhanced system accounting. An obvious CONFIG would be
>>CONFIG_BSD_PROCESS_ACCT.
> 
> 
> Right. Make all the data fields and code dependent on an appropriate 
> CONFIG_XXX macro. We talked about that a couple of weeks ago as AFAIK.
> 
> I had a look at Frank's patch and it does not seem to touch the critical 
> paths. Jay: Can you verify that the changes do not affect critical paths 
> and that accounting is still working in the right way?

Frank's patch looks fine to me except one place:
diff -ru a/mm/mmap.c b/mm/mmap.c
--- a/mm/mmap.c	2005-09-21 11:07:40.000000000 +0200
+++ b/mm/mmap.c	2005-09-21 11:17:06.755572000 +0200
@@ -854,6 +854,7 @@
  		mm->stack_vm += pages;
  	if (flags & (VM_RESERVED|VM_IO))
  		mm->reserved_vm += pages;
+	update_mem_hiwater(mm);
  }
  #endif /* CONFIG_PROC_FS */

I have a question of adding this call here. 'update_mem_hiwater'
does nothing unless mm->total_vm or rss gets updated.
I do not see total_vm get updates in __vm_stat_account()?

- jay