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    SubjectRe: [PATCH 1/5] mm: Add __GFP_NO_OOM_KILL flag
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    On Thursday 07 May 2009, Andrew Morton wrote:
    > On Thu, 7 May 2009 21:33:47 +0200
    > "Rafael J. Wysocki" <rjw@sisk.pl> wrote:
    >
    > > On Thursday 07 May 2009, Andrew Morton wrote:
    > > > On Thu, 7 May 2009 20:09:52 +0200
    > > > "Rafael J. Wysocki" <rjw@sisk.pl> wrote:
    > > >
    > > > > > > > I'm suspecting that hibernation can allocate its pages with
    > > > > > > > __GFP_FS|__GFP_WAIT|__GFP_NORETRY|__GFP_NOWARN, and the page allocator
    > > > > > > > will dtrt: no oom-killings.
    > > > > > > >
    > > > > > > > In which case, processes_are_frozen() is not needed at all?
    > > > > > >
    > > > > > > __GFP_NORETRY alone causes it to fail relatively quickly, but I'll try with
    > > > > > > the combination.
    > > > > >
    > > > > > OK. __GFP_WAIT is the big hammer.
    > > > >
    > > > > Unfortunately it fails too quickly with the combination as well, so it looks
    > > > > like we can't use __GFP_NORETRY during hibernation.
    > > >
    > > > hm.
    > > >
    > > > So where do we stand now?
    > > >
    > > > I'm not a big fan of the global application-specific state change
    > > > thing. Something like __GFP_NO_OOM_KILL has a better chance of being
    > > > reused by other subsystems in the future, which is a good indicator.
    > >
    > > I'm not against __GFP_NO_OOM_KILL, but there's been some strong resistance to
    > > adding new _GPF _FOO flags recently.
    >
    > We have six or seven left - hardly a crisis.
    >
    > > Is there any likelihood anyone else we'll
    > > really need it any time soon?
    >
    > Dunno - people do all sorts of crazy things. But it's more likely to
    > be reused than a PM-specific global!
    >
    > I have no strong feelings really, but slotting into the existing
    > technique with something which might be reusable is quite a bit tidier.

    OK, let's try with __GFP_NO_OOM_KILL first. If there's too much disagreement,
    I'll use the freezer-based approach instead.


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