Messages in this thread | | | From | Linus Torvalds <> | Date | Mon, 11 Feb 2013 20:42:37 -0800 | Subject | Re: [tip:x86/mm] x86, mm: Use a bitfield to mask nuisance get_user() warnings |
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On Mon, Feb 11, 2013 at 8:21 PM, H. Peter Anvin <hpa@zytor.com> wrote: > On 02/11/2013 07:33 PM, Linus Torvalds wrote: > >> Has anybody run this past any gcc developers? And if so, did they run >> away screaming? > > I haven't no... H.J., any comments on this patch?
I'd be most worried about any known pitfalls about bitfield code generation. Looking at your code size numbers, it actually seems to *improve* code generation except for the odd i386.pae case (bigger code but also a different data size - odd) and i386 noconfig (different bss, bigger code).
The code/data changes makes me wonder if the variable sometimes gets flushed to memory as a 8-byte entry, and maybe there are things gcc people can suggest..
But I don't see anything fundamentally wrong with it. Certainly it looks much better than the disgusting and warning-prone
unsigned long long __val_gu8
thing.
Linus
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