Re: Page Migration: Make do_swap_page redo the fault

[Hugh Dickins <hugh@veritas.com>]

On Sat, 8 Apr 2006, Christoph Lameter wrote:
> On Sat, 8 Apr 2006, Hugh Dickins wrote:
> > 
> > Sure, those are long standing checks, necessary long before migration
> > came on the scene; whereas the check in do_swap_page was recently added
> > just for a page migration case, and now turns out to be redundant.
> 
> Those two checks were added for migration together with the one we 
> are removing now. Sounds like you think they additionally fix some other 
> race conditions?

Of course, you're right - sorry.  Whatever was I looking at,
to get it so confidently wrong?  Dunno: scary.

But I do have to worry then.  I'd missed the addition of those checks:
if they really are necessary, then the rules have changed in two
tricky areas I now need to re-understand.  It'll take me a while.

Thanks for setting me straight.

Hugh

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>