Re: [PATCH] mm, hugetlb: gimme back my page

From: Davidlohr Bueso
Date: Fri Jan 31 2014 - 12:50:55 EST


On Thu, 2014-01-30 at 12:58 -0800, David Rientjes wrote:
> On Thu, 30 Jan 2014, Sasha Levin wrote:
>
> > VM_BUG_ON_PAGE is just a VM_BUG_ON that does dump_page before the BUG().
> >
> > The only reason to use VM_BUG_ON instead of VM_BUG_ON_PAGE is if the page
> > you're working
> > with doesn't make sense/isn't useful as debug output.
> >
> > If doing a dump_page is causing issues somewhere then dump_pages should be
> > fixed - instead
> > of hiding the problem under the rug by not using it.
> >
>
> It sounds like dump_page() isn't necessarily at fault itself but rather
> that using it is opening a race even wider that causes this failure to
> occur more often than it normally would.

It turns out this issue goes way back, you just have try hard enough to
trigger it under very specific conditions.

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