Re: Regression from 2.6.36

[Andrew Morton <akpm@linux-foundation.org>]

On Thu, 14 Apr 2011 04:10:58 +0200 Eric Dumazet <eric.dumazet@gmail.com> wrote:

> > --- a/fs/file.c~a
> > +++ a/fs/file.c
> > @@ -39,14 +39,17 @@ int sysctl_nr_open_max = 1024 * 1024; /*
> >   */
> >  static DEFINE_PER_CPU(struct fdtable_defer, fdtable_defer_list);
> >  
> > -static inline void *alloc_fdmem(unsigned int size)
> > +static void *alloc_fdmem(unsigned int size)
> >  {
> > -	void *data;
> > -
> > -	data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN);
> > -	if (data != NULL)
> > -		return data;
> > -
> > +	/*
> > +	 * Very large allocations can stress page reclaim, so fall back to
> > +	 * vmalloc() if the allocation size will be considered "large" by the VM.
> > +	 */
> > +	if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER) {
> > +		void *data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN);
> > +		if (data != NULL)
> > +			return data;
> > +	}
> >  	return vmalloc(size);
> >  }
> >  
> > _
> > 
> 
> Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
> 
> #define PAGE_ALLOC_COSTLY_ORDER 3
> 
> On x86_64, this means we try kmalloc() up to 4096 files in fdtable.

Thanks.  I added the cc:stable to the changelog.

It'd be nice to get this tested if poss, to confrm that it actually
fixes things.

Also, Melpoke.