Subject: Re: [PATCH] profile: Suppress warning about large allocations when profile=1 is specified

From: Arnaldo Carvalho de Melo <[email-masked]>
Date: Mon, 22 Jun 2009 14:00:15 -0300

Em Mon, Jun 22, 2009 at 12:31:05PM +0100, Mel Gorman escreveu:
> On Sat, Jun 20, 2009 at 11:48:35PM +0200, Heinz Diehl wrote:
> > On 20.06.2009, Mel Gorman wrote: 
> > 
> > > I can't figure out from this trace where the problem is coming from. Can
> > > you post your .config and the full dmesg please?
> > 
> > Yes, of course. It's attached.
> > 
> 
> I have no idea why the stack trace is so badly managed but the problem appears
> to be in DCCP so can you try the patch below please? It applies on top of the
> profile=1 patch fix. If it works for you, I'll split out the patch properly
> into three separate patches and repost.
> 
> Some questions though
> 
> 1. Could DCCP use alloc_large_system_hash()?

Possibly. Ideally this should use whatever TCP is using now, as this
came more or less intact from there. IIRC it was not shared because TCP
used/uses alloc routines that were available only at boot time, DCCP
can't use it because it can be loaded as a module.

I'd say go with this patch and later, after FISL (this week) I'll look
at this again.

So, for the NOWARN bits:

Acked-by: Arnaldo Carvalho de Melo <[email-masked]>

Thanks,

- Arnaldo
 
> 2. Any idea why the stack trace for the warning was so useless?
> 
> ==== CUT HERE ====
> dccp: Suppress warning about large allocations from DCCP
> 
> The DCCP protocol tries to allocate some large hash tables during
> initialisation using the largest size possible. The allocator warns if
> the allocations are too large but the caller is able to handle
> allocation failure. This patch disables the warnings in the case DCCP
> requests too large an allocation.
> 
> Signed-off-by: Mel Gorman <[email-masked]>
> --- 
>  net/dccp/proto.c |    4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/dccp/proto.c b/net/dccp/proto.c
> index 314a1b5..fd21676 100644
> --- a/net/dccp/proto.c
> +++ b/net/dccp/proto.c
> @@ -1066,7 +1066,7 @@ static int __init dccp_init(void)
>  		       (dccp_hashinfo.ehash_size - 1))
>  			dccp_hashinfo.ehash_size--;
>  		dccp_hashinfo.ehash = (struct inet_ehash_bucket *)
> -			__get_free_pages(GFP_ATOMIC, ehash_order);
> +			__get_free_pages(GFP_ATOMIC|__GFP_NOWARN, ehash_order);
>  	} while (!dccp_hashinfo.ehash && --ehash_order > 0);
>  
>  	if (!dccp_hashinfo.ehash) {
> @@ -1091,7 +1091,7 @@ static int __init dccp_init(void)
>  		    bhash_order > 0)
>  			continue;
>  		dccp_hashinfo.bhash = (struct inet_bind_hashbucket *)
> -			__get_free_pages(GFP_ATOMIC, bhash_order);
> +			__get_free_pages(GFP_ATOMIC|__GFP_NOWARN, bhash_order);
>  	} while (!dccp_hashinfo.bhash && --bhash_order >= 0);
>  
>  	if (!dccp_hashinfo.bhash) {