Messages in this thread | | | Date | Thu, 15 May 2008 10:26:25 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: [PATCH 0/3] explicitly document overloaded page flags |
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On Thu, 15 May 2008, Andy Whitcroft wrote:
> With the recent page flag reorganisation we have a single enum which > defines the valid page flags and their values, nice and clear. However > there are a number of bits which are overloaded by different subsystems. > Firstly there is PG_owner_priv_1 which is used by filesystems and by XEN. > Secondly both SLOB and SLUB use a couple of extra page bits to manage > internal state for pages they own; both overlay other bits. All of these > "aliases" are scattered about the source making it very hard for a reader > to know if the bits are safe to rely on in all contexts; confusion here > is bad. > > As we now have a single place where the bits are clearly assigned it makes > sense to clarify the reuse of bits by making the aliases explicit and > visible with the original bit assignments. This patch creates explicit > aliases within the enum itself for the overloaded bits and uses those > aliases throughout.
Ahh. Great! I considered doing that work too but never got around to it.
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