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    SubjectRe: [RFC][PATCH] PM: Force GFP_NOIO during suspend/resume (was: Re: [linux-pm] Memory allocations in .suspend became very unreliable)
    On Sunday 17 January 2010, Oliver Neukum wrote:
    > Am Sonntag, 17. Januar 2010 01:38:37 schrieb Rafael J. Wysocki:
    > > > Now having said that, we've been considering a change that will turn all
    > > > GFP_KERNEL allocations into GFP_NOIO during suspend/resume, so perhaps I'll
    > > > prepare a patch to do that and let's see what people think.
    > >
    > > If I didn't confuse anything (which is likely, because it's a bit late here
    > > now), the patch below should do the trick. I have only checked that it doesn't
    > > break compilation, so please take it with a grain of salt.
    > >
    > > Comments welcome.
    > I think this is a bad idea as it makes the mm subsystem behave differently
    > in the runtime and in the whole system cases.

    s/runtime/suspend/ ?

    Yes it will, but why exactly shouldn't it? System suspend/resume _is_ a
    special situation anyway.

    > What's so hard about telling people that they need to use GFP_NOIO in
    > suspend() and resume()?

    Memory allocations are made for other purposes during suspend/resume too. For
    example, new kernel threads may be created (for async suspend/resume among
    other things).

    Besides, the fact that you tell people to do something doesn't necessary imply
    that they will listen. :-)

    I have discussed that with Ben for a couple of times and we have generally
    agreed that memory allocation problems during suspend/resume are not avoidable
    in general unless we disable __GFP_FS and __GFP_IO at the high level.


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