linux-kernel - Re: [PATCH v2] slab,slub: ignore __GFP_WAIT if we're booting or suspending

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Message-ID: <20090612091002.GA32052@elte.hu>
Date:	Fri, 12 Jun 2009 11:10:02 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Pekka J Enberg <penberg@...helsinki.fi>
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org, npiggin@...e.de,
	benh@...nel.crashing.org, akpm@...ux-foundation.org,
	cl@...ux-foundation.org, torvalds@...ux-foundation.org
Subject: Re: [PATCH v2] slab,slub: ignore __GFP_WAIT if we're booting or
	suspending


* Pekka J Enberg <penberg@...helsinki.fi> wrote:

> index 3964d3c..6387c19 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -1548,6 +1548,20 @@ new_slab:
>  		goto load_freelist;
>  	}
>  
> +	/*
> +	 * Lets not wait if we're booting up or suspending even if the user
> +	 * asks for it.
> +	 */
> +	if (system_state != SYSTEM_RUNNING)
> +		gfpflags &= ~__GFP_WAIT;

Hiding that bug like that is not particularly clean IMO. We should 
not let system_state hacks spread like that.

We emit a debug warning but dont crash, so all should be fine and 
the culprits can then be fixed, right?

	Ingo
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