Messages in this thread |  | | | Date | Mon, 06 Nov 2006 12:47:35 +0200 | | From | Avi Kivity <> | | Subject | Re: [PATCH 1/14] KVM: userspace interface |
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Arjan van de Ven wrote: >> \> as a general rule, it's a lot better to sort structures big-to-small, to >> >>> make sure alignments inside the struct are minimized and don't suck too >>> much. This is especially important to get right for 32/64 bit >>> compatibility. This comment is true for most structures in this header >>> file; please consider this at least >>> >>> >> Doesn't that cause an unnatural field order? >> > > Does it matter? > >
Just a matter of taste.
>> for example, in some >> structures I separated in and out variables. Sorting by size is a bit >> like sorting alphabetically. >> >> Anyway I observed 32/64 bit compatibility religiously. >> > > but you did take the alignment rules of 64 bit variables into account, > eg 32 bit has it 4 byte aligned, while 64 bit has it 8 byte aligned.. > you are 100% sure even your 32 bit structures have all 64 bit values 8 > byte aligned? > (you get this automatic if you sort by size) > Also you made sure that if you have such implicit padding that you zero > out the memory between the fields to avoid information leaks? >
I put explicit padding everywhere.
> Sorting by size at least makes this all go away..... > >
True. I'll rethink it.
-- error compiling committee.c: too many arguments to function
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