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SubjectRe: [PATCH 0/7] Kill PF_MEMALLOC abuse
On Tue, 17 Nov 2009, KOSAKI Motohiro wrote:

> > I agree in principle with removing non-VM users of PF_MEMALLOC, but I
> > think it should be left to the individual subsystem maintainers to apply
> > or ack since the allocations may depend on the __GFP_NORETRY | ~__GFP_WAIT
> > behavior of PF_MEMALLOC. This could be potentially dangerous for a
> > PF_MEMALLOC user if allocations made by the kthread, for example, should
> > never retry for orders smaller than PAGE_ALLOC_COSTLY_ORDER or block on
> > direct reclaim.
>
> if there is so such reason. we might need to implement another MM trick.
> but keeping this strage usage is not a option. All memory freeing activity
> (e.g. page out, task killing) need some memory. we need to protect its
> emergency memory. otherwise linux reliability decrease dramatically when
> the system face to memory stress.
>

Right, that's why I agree with trying to remove non-VM use of PF_MEMALLOC,
but I think this patchset needs to go through the individual subsystem
maintainers so they can ensure the conversion doesn't cause undesirable
results if their kthreads' memory allocations depend on the __GFP_NORETRY
behavior that PF_MEMALLOC ensures. Otherwise it looks good.


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