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

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Date:	Fri, 12 Jun 2009 12:49:17 +0300
From:	Pekka Enberg <penberg@...helsinki.fi>
To:	Ingo Molnar <mingo@...e.hu>
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

On Fri, Jun 12, 2009 at 12:10 PM, Ingo Molnar<mingo@...e.hu> wrote:
>> @@ -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?

OK, lets not use system_state then and go with Ben's approach then.
Again, neither of the patches are about "hiding buggy callers" but
changing allocation policy wrt. gfp flags during boot (and later on
during suspend).

                                 Pekka
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