Re: [PATCH 0/5] Candidate fix for increased number of GFP_ATOMIC failures V2

[Karol Lewandowski <karol.k.lewandowski@gmail.com>]

On Thu, Oct 22, 2009 at 03:22:31PM +0100, Mel Gorman wrote:

[Cut everything but my bug]
> [Bug #14265] ifconfig: page allocation failure. order:5, mode:0x8020 w/ e100
> 	Karol Lewandows reported that e100 fails to allocate order-5
> 	GFP_ATOMIC when loading firmware during resume. This has started
> 	happening relatively recent.


> Test 1: Verify your problem occurs on 2.6.32-rc5 if you can

Yes, bug is still there.


> Test 2: Apply the following two patches and test again
> 
>   1/5 page allocator: Always wake kswapd when restarting an allocation attempt after direct reclaim failed
>   2/5 page allocator: Do not allow interrupts to use ALLOC_HARDER
> 
> 
> 	These patches correct problems introduced by me during the 2.6.31-rc1
> 	merge window. The patches were not meant to introduce any functional
> 	changes but two were missed.
> 
> 	If your problem goes away with just these two patches applied,
> 	please tell me.

Likewise.


> Test 3: If you are getting allocation failures, try with the following patch
> 
>   3/5 vmscan: Force kswapd to take notice faster when high-order watermarks are being hit
> 
> 	This is a functional change that causes kswapd to notice sooner
> 	when high-order watermarks have been hit. There have been a number
> 	of changes in page reclaim since 2.6.30 that might have delayed
> 	when kswapd kicks in for higher orders
> 
> 	If your problem goes away with these three patches applied, please
> 	tell me

No, problem doesn't go away with these patches (1+2+3).  However, from
my testing this particular patch makes it way, way harder to trigger
allocation failures (but these are still present).

This bothers me - should I test following patches with or without
above patch?  This patch makes bug harder to find, IMVHO it doesn't
fix the real problem.

(Rest not tested yet.)

Thanks.

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