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

[Jay Lan]

Frank van Maarseveen wrote:
> On Wed, Sep 21, 2005 at 10:39:01AM -0700, Jay Lan wrote:
>
> > 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()?
>
>
> Check the callers of __vm_stat_account(). It is called at various places
> after increasing (sometimes decreasing) vm_total.

Sounds good.

- jay


> BTW, __vm_stat_account() itself is surrounded by #ifdef CONFIG_PROC_FS so
> I'd thought that that might be appropriate for hiwater_* too. So far they are
> set but are not read except by my patch for /proc/pid/status. >
> in 2.6.13.2:
>
> $ find -type f|xargs grep hiwater_rss
> ./kernel/fork.c:        mm->hiwater_rss = get_mm_counter(mm,rss);
> ./include/linux/sched.h:        unsigned long hiwater_rss;      /* High-water RSS usage */
> ./mm/memory.c:          if (tsk->mm->hiwater_rss < rss)
> ./mm/memory.c:                  tsk->mm->hiwater_rss = rss;
> ./mm/nommu.c:           if (tsk->mm->hiwater_rss < rss)
> ./mm/nommu.c:                   tsk->mm->hiwater_rss = rss;
>
> $ find -type f|xargs grep hiwater_vm 
> ./kernel/fork.c:        mm->hiwater_vm = mm->total_vm;
> ./include/linux/sched.h:        unsigned long hiwater_vm;       /* High-water virtual memory usage */
> ./mm/memory.c:          if (tsk->mm->hiwater_vm < tsk->mm->total_vm)
> ./mm/memory.c:                  tsk->mm->hiwater_vm = tsk->mm->total_vm;
> ./mm/nommu.c:           if (tsk->mm->hiwater_vm < tsk->mm->total_vm)
> ./mm/nommu.c:                   tsk->mm->hiwater_vm = tsk->mm->total_vm;
>
> The matches in mm/memory.c and mm/nommu.c are in function update_mem_hiwater().

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