Re: [PATCH 04/16] page-flags: define PG_locked behavior on compound pages

From: Kirill A. Shutemov
Date: Thu Sep 24 2015 - 16:26:27 EST

On Thu, Sep 24, 2015 at 11:08:29AM -0500, Christoph Lameter wrote:
> On Thu, 24 Sep 2015, Kirill A. Shutemov wrote:
> > SLUB uses PG_locked as a bit spin locked. IIUC, tail pages should never
> > appear there. VM_BUG_ON() is added to make sure that this assumption is
> > correct.
> Correct. However, VM_BUG_ON is superfluous. If there is a tail page there
> then the information in the page will be not as expected (free list
> parameter f.e.) and things will fall apart rapidly with segfaults.

Right. But would it provide any clues on what is going on?

Kirill A. Shutemov
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