[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] X86 arch_domain ginormous, sizeof(struct domain) already == PAGE_SIZE
On 29/01/16 17:09, Jan Beulich wrote: >>>> On 29.01.16 at 17:24, <czuzu@xxxxxxxxxxxxxxx> wrote: >> To investigate I compiled the unaltered domain.c & used the pahole tool >> (part of dwarves package) to obtain the complete layout of the domain >> structure (& its members). >> What I obtained: >> * sizeof(struct domain) is already = 4096 bytes (= PAGE_SIZE) >> * sizeof(struct arch_domain) [x86] = sizeof(domain.arch) = 3328 >> bytes (arch_domain is marked __cacheline_aligned, i.e. aligned to 128 bytes) >> * sizeof(domain.arch.hvm_domain) = 2224 bytes >> * sizeof(domain.arch.hvm_domain.pl_time) = 1088 bytes >> >> => overall, X86 timers-related information occupies the most. >> >> One could shrink the domain structure by transforming some of its fields >> to pointers, e.g. I could transform the pl_time field into a pointer and >> dynamically allocate its data when domain_create is called. > Sounds like a reasonable measure. I wasn't aware we're exactly on > the boundary right now. It has been teatering on the edge for a while now. I keep on meaning to see about sliming it down somewhat (probably by pulling an optional structure out into an explicit allocation), but haven't had the time. ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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