Messages in this thread | | | Date | Thu, 6 May 2010 18:40:39 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: [PATCH 2/2] mm,migration: Fix race between shift_arg_pages and rmap_walk by guaranteeing rmap_walk finds PTEs created within the temporary stack |
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On Fri, 7 May 2010, Mel Gorman wrote: > > Page migration requires rmap to be able to find all migration ptes > created by migration. If the second rmap_walk clearing migration PTEs > misses an entry, it is left dangling causing a BUG_ON to trigger during > fault. For example;
So I still absolutely detest this patch.
Why didn't the other - much simpler - patch work? The one Rik pointed to:
http://lkml.org/lkml/2010/4/30/198
and didn't do that _disgusting_ temporary anon_vma?
Alternatively, why don't we just take the anon_vma lock over this region, so that rmap can't _walk_ the damn thing?
Linus
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